tag:theconversation.com,2011:/africa/topics/little-ice-age-7384/articlesLittle Ice Age – The Conversation2023-08-31T22:28:00Ztag:theconversation.com,2011:article/2095722023-08-31T22:28:00Z2023-08-31T22:28:00ZHow analyzing ancient and modern polar bear samples reveals the full scope of global warming<figure><img src="https://images.theconversation.com/files/545815/original/file-20230831-3676-ueot5v.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5061%2C3239&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Analyzing samples of polar bears can reveal not only what they ate but also the food web during their lives. Polar bears pictured live in captivity.</span> <span class="attribution"><span class="source">(AP Photo/Ronald Zak)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/how-analyzing-ancient-and-modern-polar-bear-samples-reveals-the-full-scope-of-global-warming" width="100%" height="400"></iframe>
<p>The global climate is changing and the <a href="https://www.ipcc.ch/srocc/">Arctic is warming rapidly</a>. These are objectively true statements that most people have come to accept. </p>
<p>But it is also true that <a href="https://climate.nasa.gov/evidence/#:%7E:text=Earth's%20climate%20has%20changed%20throughout%20history.,era%20%E2%80%94%20and%20of%20human%20civilization.">Earth’s climate has never been stagnant</a> and climate anomalies have been frequent throughout the past. </p>
<p>How then, do we understand our current situation relative to past climate shifts? Are the impacts of modern climate change comparable to those of the medieval warm period (MWP) or the little ice age (LIA)? </p>
<p>Our <a href="https://www.sciencedirect.com/science/article/pii/S2213305423000309">recently published study in <em>Anthropocene</em></a> demonstrates a much more substantial impact to polar bears resulting from recent climate change compared to observations over the last 4,000 years. This suggests that current climatic changes are, indeed, unprecedented in human history.</p>
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Read more:
<a href="https://theconversation.com/arctic-report-card-2022-the-arctic-is-getting-rainier-and-seasons-are-shifting-with-broad-disturbances-for-people-ecosystems-and-wildlife-196254">Arctic Report Card 2022: The Arctic is getting rainier and seasons are shifting, with broad disturbances for people, ecosystems and wildlife</a>
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<h2>Ecosystem background</h2>
<p>Predators at the top of the food chain, like polar bears, <a href="https://link.springer.com/chapter/10.1007/978-1-4612-3498-2_12">reflect changes across the entire ecosystem</a>, all the way down to microscopic algae. </p>
<p>In the Arctic, the base of the food web is sourced from two categories: sea ice-associated algae and open-water phytoplankton, <a href="https://link.springer.com/article/10.1007/s003000050311">which are distinguishable</a> through their carbon isotopes. </p>
<p>In our study area — centred on Lancaster Sound in the Canadian Arctic Archipelago — the food web is fed by a combination of both sea ice algae and phytoplankton. We can assess the relative importance of these two sources through the stable isotopes incorporated into the tissues of animals. </p>
<p>The relative abundance of carbon isotopes does not change as they are transferred through the food web, so these isotopes tell us about <a href="https://www.sciencedirect.com/science/article/abs/pii/0016703778901990">the carbon sources</a> at the base of the food web. <a href="https://esajournals.onlinelibrary.wiley.com/doi/pdfdirect/10.1890/0012-9658(2002)083%5B0703:USITET%5D2.0.CO;2?casa_token=q3M0nAeb-1EAAAAA:p92TARKS7YYyUbX1G0S0YUVN31DqA99kLhmtsC2m178YoxEDkb6olrt_Kcjp5AtTqmvB0i4wKtUa">Nitrogen isotopes do change</a> as they are passed up the food chain, which tells us who is eating whom.</p>
<h2>Results from our study</h2>
<p>In our study we examined stable carbon and nitrogen isotopes in polar bear bone collagen. </p>
<p>The polar bears were all from the Lancaster Sound sub-population and spanned the last 4,000 years. We acquired samples of modern polar bear (1998-2007) obtained through hunting and we were able to compare them to samples from archaeological excavations conducted in the region. </p>
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<figcaption><span class="caption">National Geographic overview of the life-cycle and eating habits of polar bears.</span></figcaption>
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<p>The span of time captured by the archaeological samples was vast, but by dividing them into time bins associated with the <a href="https://www.avataq.qc.ca/en/L-institut/Departements/Archeologie/Decouvrir-l-archeologie/Chronologie-de-l-Arctique">cultural traditions in the region</a> we were able to compare the samples across time before present (BP): pre-Dorset (4000-2800 years BP), Dorset (1500-700 BP) and Thule (700-500 BP). </p>
<p>The Dorset/Thule cultural transition occurred at the onset of the medieval warm period, so a comparison of these time bins allows us to look at the state of the food web before and during a known climate shift. The Thule time bin also extends into the beginning of the little ice age giving us a glimpse into that period as well.</p>
<h2>What it all means</h2>
<p>First, the good news. The results of the nitrogen isotopes showed that throughout time, 4,000 years BP to the present, the structure of the Lancaster Sound food web was relatively unchanged. Polar bears eat seals, seals eat cod, cod eat zooplankton, et cetera. There were no surprising shifts in the diets of polar bears despite past and present climate change. This is comforting.</p>
<p>The results of the carbon isotopes tell a less encouraging story, however. Throughout the four millennia encapsulated by the ancient time bins, we saw stability in the mixture of sea ice algae and open water phytoplankton. We did not detect a difference in the origin of carbon at the base of the food web resulting from the medieval warm period or the little ice age. </p>
<p>The modern samples, however, showed a significant difference in the source of carbon, resulting from a greater proportion of open water phytoplankton and less reliance on sea ice algae.</p>
<h2>Evidence of a warming climate</h2>
<p>Sea ice is an important habitat in the high Arctic. For polar bears it is a platform for hunting. For ringed seals, the <a href="https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/06-0546.1?casa_token=v_UExbec6wcAAAAA%3ALGGzkOG-_AsVsjYSgbln1STf38Upm3hjHZQO2mIm1h_Z_f9LerBLBjMw_0D4Eo15WoUO0VgiXDpE">primary prey of polar bears</a>, it is a platform for denning and raising young.</p>
<p>The algae that grows in association with sea ice is also very important for <a href="https://www.sciencedirect.com/science/article/abs/pii/S0079661115001640">jumpstarting biological productivity</a> before the open water season. Our study shows that the loss of biological productivity associated with sea ice is unprecedented on a very long timescale.</p>
<p>Archaeological materials can provide valuable context to the ongoing climate discussion. Much of the valuable work being undertaken is tracking ecosystem changes on a short timescale, seasons to decades. But as we have demonstrated, the Arctic has already changed, so we should not always assume that we are looking at a pristine or undisturbed state. </p>
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Read more:
<a href="https://theconversation.com/human-garbage-is-a-plentiful-but-dangerous-source-of-food-for-polar-bears-finding-it-harder-to-hunt-seals-on-dwindling-sea-ice-183968">Human garbage is a plentiful but dangerous source of food for polar bears finding it harder to hunt seals on dwindling sea ice</a>
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<p>Adding a lens that looks back into the distant past gives resolution and context to our collective understanding of our situation. </p>
<p>In this case, we have illustrated the magnitude of difference occurring in the modern Arctic, relative to past climate anomalies. The medieval warm period and onset of the little ice age were not visible in the isotopes of the Lancaster Sound food web but modern warming is very apparent. We can, therefore, not dismiss calls to action on climate change on the basis that the climate has always fluctuated.</p><img src="https://counter.theconversation.com/content/209572/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This research received funding from an NSERC Discovery grant and the Canada Research Chairs program. </span></em></p>Comparison of modern and archaeological polar bears indicates that four millennia of food web stability has been disrupted by modern climate change.Jennifer Routledge, PhD Candidate, Environmental and Life Sciences, Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2031852023-04-05T20:03:35Z2023-04-05T20:03:35Z‘Like blood, then turned into darkness’: how medieval manuscripts link lunar eclipses, volcanoes and climate change<figure><img src="https://images.theconversation.com/files/519148/original/file-20230403-17-t8wel.jpg?ixlib=rb-1.1.0&rect=445%2C222%2C3456%2C2430&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A diagram of a lunar eclipse from De Sphaera Mundi by Johannes de Sacrobosco, c. 1240 AD.</span> <span class="attribution"><a class="source" href="https://digitalcollections.nypl.org/items/148cf2c0-f054-0138-15e1-0242ac110003">New York Public Library</a></span></figcaption></figure><p>Before humans started heating the planet by burning fossil fuels in the 19th century, Earth had experienced centuries-long widespread cool period known as the Little Ice Age.</p>
<p>Scientists believe this cold spell may have been <a href="https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2011GL050168">triggered, in part, by volcanic eruptions</a> which made the atmosphere hazier, blocking some incoming sunlight. </p>
<p>Records of these eruptions are sparse, and much of our knowledge of them comes from the traces left behind in <a href="https://www.nature.com/articles/s41467-019-08357-0">polar ice</a> and <a href="https://www.sciencedirect.com/science/article/abs/pii/S0277379115301888">tree rings</a>, which are fragmentary and sometimes contradictory.</p>
<p>In a <a href="https://www.nature.com/articles/s41586-023-05751-z">new study published in Nature</a>, an international team of researchers led by Sébastien Guillet at the University of Geneva has found another way to learn about these historical eruptions: by studying descriptions of lunar eclipses in medieval manuscripts.</p>
<h2>Dark eclipses</h2>
<p>The researchers compiled hundreds of records of lunar eclipses from across Europe, the Middle East, and Asia, documenting 187 eclipses between 1100 and 1300. </p>
<p>In particular, they searched for descriptions that provided information on the brightness and colour of the Moon during the eclipse. Most of these turned out to be from European monks or clerics, writing in Latin.</p>
<p>Based on these descriptions, the researchers ranked the colour and brightness of the Moon reported in each total eclipse. The brighter the eclipse, the clearer the atmosphere at the time: darker eclipses indicated a higher level of aerosol particles in the upper atmosphere – a marker of recent volcanic activity.</p>
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<img alt="" src="https://images.theconversation.com/files/519473/original/file-20230405-18-65dlb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/519473/original/file-20230405-18-65dlb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/519473/original/file-20230405-18-65dlb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/519473/original/file-20230405-18-65dlb3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/519473/original/file-20230405-18-65dlb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/519473/original/file-20230405-18-65dlb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/519473/original/file-20230405-18-65dlb3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">During a total lunar eclipse, the Moon turns red due to sunlight refracted by Earth’s atmosphere. A particularly dark eclipse indicates more aerosols in the atmosphere, which is a sign of recent volcanic activity.</span>
<span class="attribution"><span class="source">Chris Harwood / Shutterstock</span></span>
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<p>The next step was to put the eclipse data together with simulations of how aerosol particles behave in the atmosphere, modern satellite observations, and climatic evidence from historical tree ring records. </p>
<p>This allowed the researchers to estimate the timing of the culprit eruptions more precisely than from previous ice core records – and determine which eruptions reached the stratosphere and would be more likely to generate climatic cooling effects.</p>
<h2>What lunar eclipses tell us about the state of the atmosphere</h2>
<p>A total lunar eclipse is a beautiful sight. When the Sun, Earth and Moon align perfectly, our planet blocks direct sunlight from reaching the Moon’s surface. </p>
<p>However, Earth’s atmosphere bends sunlight around our planet. As a result, some sunlight reaches the Moon even during a total eclipse. </p>
<p>Earth’s atmosphere also scatters sunlight - acting as a giant colour filter. The bluer the light, the more it is scattered – which is why the sky is blue in the daytime, and why the Sun appears ruddy at dawn and dusk.</p>
<p>During a total lunar eclipse, the sunlight reaching the Moon has been filtered by Earth’s atmosphere, removing much of the blue and yellow light. The light that reaches the Moon is effectively the sum of all the dawns and all the dusks occurring at that time. </p>
<p>And the state of Earth’s atmosphere at that time controls just how much light is filtered. </p>
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<figcaption><span class="caption">NASA video released to explain the total Lunar eclipse seen from the Americas in December 2011.</span></figcaption>
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<h2>How volcanoes affect lunar eclipses</h2>
<p>If you’ve ever seen a sunset during a dust storm, or on a very smoky day, you know the extra particles clogging up the sky can produce deep, vibrant reds and oranges.</p>
<p>Imagine a total lunar eclipse occurring while wildfires rage overseas. The fires would pump smoke and dust into Earth’s atmosphere, making the Moon redder and darker during the eclipse. </p>
<p>Which brings us to the effect of volcanoes. The largest volcanic eruptions pump vast amounts of material into Earth’s stratosphere, where it can remain for many months. </p>
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<p>The spectacular volcanic sunsets seen throughout Australia in the months following the Tongan volcanic eruption of January 2022 are a great example. And that material, once in the stratosphere, will spread around Earth.</p>
<p>What effect does this have on lunar eclipses? It turns out the brightness of the Moon during a lunar eclipse depends the amount of material in our stratosphere. In the months after a large eruption, any lunar eclipse would be markedly darker than normal.</p>
<h2>How volcanoes affect the climate</h2>
<p>Volcanic eruptions can eject huge amounts of ash, sulphur dioxide, and other gases high into the atmosphere. Eruptions can cause either cooling or warming (both temporary). The effect depends on exactly what the volcano spews out, how high the plume reaches, and the volcano’s location.</p>
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Read more:
<a href="https://theconversation.com/climate-explained-how-volcanoes-influence-climate-and-how-their-emissions-compare-to-what-we-produce-125490">Climate explained: how volcanoes influence climate and how their emissions compare to what we produce</a>
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<p>Sulphur dioxide is particularly important. If it reaches the stratosphere, it reacts with water vapour to form a lingering veil of sulphate aerosols. These aerosols, along with the volcanic ash, block and scatter Solar radiation, often leading to cooling at the Earth’s surface.</p>
<p>Large volcanic eruptions, such as the <a href="https://earthobservatory.nasa.gov/images/1510/global-effects-of-mount-pinatubo">1991 Mount Pinatubo eruption</a> in the Philippines and the infamous <a href="https://www.cambridge.org/core/journals/quaternary-research/article/abs/historic-eruptions-of-tambora-1815-krakatau-1883-and-agung-1963-their-stratospheric-aerosols-and-climatic-impact/13CE8FA2B0EF3BE25951FB759F904446">1815 eruption of Tambora</a> in Indonesia, slightly lowered global temperature in the years after the eruption. After Tambora, Europe and North America experienced a “<a href="https://iopscience.iop.org/article/10.1088/1748-9326/ab3a10">year without a summer</a>” in 1816.</p>
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<span class="caption">The plume of ash and smoke from the 2022 Hunga Tonga-Hunga Ha'apai eruption was visible from the International Space Station.</span>
<span class="attribution"><span class="source">EPA / NASA / Kayla Barron</span></span>
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<p>On the other hand, water vapour and carbon dioxide from volcanic eruptions have a warming effect. It’s only small, as all present-day volcanic emissions produce <a href="https://www.usgs.gov/programs/VHP/volcanoes-can-affect-climate">less than 1%</a> of the carbon dioxide released by human activities. </p>
<h2>The past and future of volcanoes, eclipses, and the climate</h2>
<p>Eyewitness accounts through historical reports and oral traditional knowledge are often overlooked in the study of volcanoes. However, the inclusion of broader sources of knowledge is incredibly valuable to help us understand past impacts of volcanic eruptions on people and the environment.</p>
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Read more:
<a href="https://theconversation.com/when-the-bullin-shrieked-aboriginal-memories-of-volcanic-eruptions-thousands-of-years-ago-81986">When the Bullin shrieked: Aboriginal memories of volcanic eruptions thousands of years ago</a>
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<p>In this study, the combination of historical observations with ice records and climate reconstructions from tree rings has enabled more precise timing of those ancient eruptions. In turn, this has allowed us to better understand their potential impact on the climate during the European Middle Ages. Such information can help us to understand the role these eruptions may have played in the transition to the Little Ice Age.</p>
<p>In the future, volcanoes may have to work a little harder to create a “dark” eclipse. As the atmosphere warms, the altitude of the stratosphere will increase. As a result, it may take a bigger eruption to put significant amounts of aerosols into the upper layer where they will hang around to darken the Moon for future generations!</p><img src="https://counter.theconversation.com/content/203185/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Heather Handley receives funding from the Australian Research Council. She is Co-Founder of Women in Earth and Environmental Sciences Australasia (WOMEESA) and Co-Founder and Director of the Earth Futures Festival.</span></em></p><p class="fine-print"><em><span>Jonti Horner does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Medieval monks recorded hundreds of lunar eclipses. Centuries later, their descriptions are helping scientists unravel the role of volcanoes in historical climate change.Heather Handley, Associate Professor of Volcanology and Geoscience Communication, University of Twente and Adjunct Associate Professor, Monash UniversityJonti Horner, Professor (Astrophysics), University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1902132022-10-13T17:24:29Z2022-10-13T17:24:29ZDespite its long history of wildfires, Canada still doesn’t know how to live with them<figure><img src="https://images.theconversation.com/files/489266/original/file-20221011-13-yrd2is.jpg?ixlib=rb-1.1.0&rect=33%2C67%2C2779%2C1695&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The growing instances of intensifying wildfires suggest that we have yet to learn to live with the fires.</span> <span class="attribution"><span class="source">THE CANADIAN PRESS/Jonathan Hayward</span></span></figcaption></figure><p>In the fall of 1922, the city of <a href="https://torontoist.com/2014/10/historicist-the-great-fire-of-1922/">Toronto sent 85 surplus streetcars to Haileybury and other northern Ontario</a> towns to help house thousands of desperate people who had lost their homes to wildfires.</p>
<p>Known as the Great Fire, it burned nearly 1,700 square kilometres of the area — including the town of Haileybury. It killed 43 people and caused millions of dollars in property damage in 18 townships. A newspaper referred to it as the “worst disaster that had ever overtaken northern Ontario.”</p>
<p>It was not. </p>
<p>The wildfires back then were as fierce, deadly and eerily similar to the ones we have today. And we have yet to learn to live with them.</p>
<h2>Fires of the past</h2>
<p>The <a href="https://www.cbc.ca/news/canada/new-brunswick/nb-author-great-miramichi-fire-remember-1.5751761">Great Miramichi fire</a>, which destroyed forests and devastated communities across northern New Brunswick in 1825, was the <a href="https://www.mqup.ca/miramichi-fire--the-products-9780228001485.php">largest and one of the most deadly wildfires</a> in North American history. </p>
<p>The <a href="https://todayinottawashistory.wordpress.com/2014/08/20/the-great-fire-of-1870/">Saguenay and Ottawa Valley fires in 1870</a> could have been just as deadly when they forced the evacuations of several thousand people. The capital city would have burned down that summer had it not been for a quick-thinking engineer who ordered the gates of the St. Louis dam on the Rideau Canal to be breached so that it would flood city streets.</p>
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<img alt="A black and white image of a burning city." src="https://images.theconversation.com/files/489434/original/file-20221012-15-c3tqqd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489434/original/file-20221012-15-c3tqqd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=334&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489434/original/file-20221012-15-c3tqqd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=334&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489434/original/file-20221012-15-c3tqqd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=334&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489434/original/file-20221012-15-c3tqqd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=420&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489434/original/file-20221012-15-c3tqqd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=420&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489434/original/file-20221012-15-c3tqqd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=420&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">The Porcupine fire, which levelled numerous towns in Ontario and killed 73 people, was followed by a deadlier fire that killed 223 people five years later.</span>
<span class="attribution"><span class="source">(National Archives of Canada-Henry Peters)</span></span>
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</figure>
<p><a href="https://www.history.com/this-day-in-history/massive-fire-burns-in-wisconsin">Seventeen villages were levelled in Wisconsin</a> the following year, killing between 1,200 and 1,500 people.</p>
<p>In 1881, the <a href="https://news.umich.edu/fires-ravaged-michigans-thumb-in-1871-1881/">Michigan’s Thumb fires</a> burned 1,480 barns, 1,521 houses and 51 schools, while killing 283 people and injuring many others. <a href="https://eminetracanada.com/how-indigenous-people-were-blamed-for-wildfire-devastation/657404/">Smoke from those fires</a> coloured the sky over Toronto.</p>
<p>In 1908, <a href="https://tourismfernie.com/history/the-great-fire-of-1908">the British Columbia town of Fernie was levelled by a wildfire</a>. In 1911, the <a href="https://www.historynerd.ca/2017/08/21/south-porcupine-burns-1911/">Porcupine fire</a> killed 73 people while levelling the towns of South Porcupine and Pottsville in Ontario before partially destroying Golden City and Porquis Junction.</p>
<p>There was almost no warning five years later when a <a href="https://www.timminspress.com/opinion/columnists/communities-were-ravaged-shaped-by-historic-fires">deadlier complex of fires swept through the same region and killed 223 people</a>.</p>
<p>Each summer and fall, it seemed, ended badly somewhere.</p>
<h2>Déjà vu</h2>
<p>The similarities between the fires now and then are uncanny, as described in my book <a href="https://www.mqup.ca/dark-days-at-noon-products-9780228012092.php?page_id=46&"><em>Dark Days At Noon: The Future of Fire</em></a>.
The ignition of fires between 1870 and 1922 was fuelled by higher temperatures, drier forests and the kind of elevated lightning activity that we are experiencing today. </p>
<p>Much of the warming back then can be attributed to the end of the little ice age (1300 to 1850) <a href="https://theconversation.com/the-original-climate-crisis-how-the-little-ice-age-devastated-early-modern-europe-178187">that dramatically cooled parts of the world</a>, and the <a href="https://theconversation.com/the-industrial-revolution-kick-started-global-warming-much-earlier-than-we-realised-64301">Industrial Revolution</a> in the late 18th and early 19th centuries.</p>
<figure class="align-center ">
<img alt="Plumes of smoke rise from a power plant" src="https://images.theconversation.com/files/489437/original/file-20221012-5658-7sx1fo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489437/original/file-20221012-5658-7sx1fo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=445&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489437/original/file-20221012-5658-7sx1fo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=445&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489437/original/file-20221012-5658-7sx1fo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=445&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489437/original/file-20221012-5658-7sx1fo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=560&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489437/original/file-20221012-5658-7sx1fo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=560&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489437/original/file-20221012-5658-7sx1fo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=560&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The burning of fossil fuels is primarily responsible for the higher temperatures that fuel wildfires.</span>
<span class="attribution"><span class="source">(AP Photo/Czarek Sokolowski)</span></span>
</figcaption>
</figure>
<p>Today, <a href="https://www.nrdc.org/stories/fossil-fuels-dirty-facts">the unprecedented warming</a> taking place is primarily because of the burning of fossil fuels.</p>
<p>Forest land-grabbing and negligence has also fuelled numerous fires in the past and present.</p>
<p>Before and beyond the turn of the <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/temperate-forest">19th century, people moved into boreal and temperate forests</a> to take advantage of cheap land and jobs in the mining and forestry sectors. Today, people are building <a href="https://www.theglobeandmail.com/real-estate/vancouver/article-a-pandemic-fed-urge-to-ramble-sending-bc-real-estate-prices-soaring/">luxurious country homes in places like the Okanagan</a> to escape the cost of living in big cities.</p>
<p>Sparks from trains and the careless disposal of locomotive ash accounted for a <a href="https://pubs.cif-ifc.org/doi/pdf/10.5558/tfc2014-062?download=true">significant number of fires in Ontario in the past</a>. Following the Lytton fire in B.C. in 2021, the head of Canada’s Transportation Safety Board acknowledged <a href="https://www.radionl.com/2021/10/18/tsb-says-more-needs-to-be-done-to-prevent-train-caused-wildfires-as-risk-grows-due-to-climate-change/">that more work is still needed to prevent wildfires caused by trains</a>.</p>
<h2>Gaps in public policy</h2>
<p>The other thing that hasn’t changed much is public policy. The Porcupine fire in 1911 as Canada’s version of the Big Burn, a <a href="https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5444731.pdf">complex of fires</a> that swept through the northern Rockies of the United States in 1910 and resulted in sweeping policy changes.</p>
<figure class="align-center ">
<img alt="A black and white image of a mountain on fire" src="https://images.theconversation.com/files/489444/original/file-20221012-24-u7i2zu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489444/original/file-20221012-24-u7i2zu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=462&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489444/original/file-20221012-24-u7i2zu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=462&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489444/original/file-20221012-24-u7i2zu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=462&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489444/original/file-20221012-24-u7i2zu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=580&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489444/original/file-20221012-24-u7i2zu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=580&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489444/original/file-20221012-24-u7i2zu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=580&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The destruction caused by the Big Burn of 1910 pushed the U.S. to revamp its wildfire management strategy.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/fsnorthernregion/4929769257/in/photolist-8vCmDF-E3z8q2-ocmRsX-oczB4b-nVazPY-nVaFKr-EYbEUi-wZokmD-ovsbmw-ouqN9h-eeGCiQ-iGtZEn-sGrZef-ow9NqC-2hynMFE-of2i3p-ocvh2o-g1vNoQ-ocE6sF-tmU217-ocmSbv-nVbbg2-nV9Xyd-ocuUEf-oczYuh-ocmRot-E3f9vC-EXDNjS-ERLp3i-Eru2nD-wjPumv-eeGLaG-eeGSsU-eeGSKC-eeGRbN-eeBfkP-eeB4YF-eeGK43-eeB9v2-eeB31K-preajL-eeATZk-EFNdEa-roXP8k-xgQukD-oeSiDc-ocE6Vp-oczYeC-oczB6f-oaBNRw">(Forest Service Northern Region/flickr)</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Following the Big Burn, the U.S. passed the <a href="https://foresthistory.org/research-explore/us-forest-service-history/policy-and-law/the-weeks-act/">Weeks Act</a> that authorized the government to purchase up to 30 million hectares of land to protect watersheds from development and wildfire. This mandated the U.S. Forest Service to work with state fire bureaus, which were happy to co-operate because it came with funding they could not otherwise afford.</p>
<p>In contrast, Canadian politicians failed to do what was necessary to prevent future fires. The government, which owned many of the railroad companies, <a href="https://www.mqup.ca/dark-days-at-noon-products-9780228012092.php?page_id=46&">blamed Indigenous people for many fires</a>. Better legislation and fire management strategies were still not in place five years after the Porcupine fire when the Matheson fire took the lives of 223 people. Nor were they there in 1922, when the Great Fire devastated Haileybury. </p>
<p>Canada had a chance to replicate what the U.S. Forest Service was doing, but failed to as funding for fire research and management was badly decimated by budget cuts and the off-loading of responsibilities to the provinces in the 1930s. </p>
<p>Even today, provinces like Alberta have <a href="https://www.firefightingincanada.com/alberta-cuts-millions-from-wildfire-management-budget-22839/">cut wildfire budgets</a> to save money, only to pay the price when wildfires like the 2016 Fort McMurray wildfire, which forced the <a href="https://www.theweathernetwork.com/ca/news/article/this-day-in-weather-history-may-3-2016-fort-mcmurray-evacuations-begin">evacuation of 88,000 people</a>.</p>
<h2>Managing future fires</h2>
<p>The fact that fire is still entering towns like Lytton and Fort McMurray without adequate warning suggests we have yet to learn to live with the fires that we have stoked by burning fossil fuels, <a href="https://theconversation.com/how-to-fight-wildfires-and-climate-change-with-wetlands-117356">draining wetlands </a> and suppressing natural fires that would have otherwise produced more resilient forests. </p>
<p>Stopping Indigenous burning that <a href="https://phys.org/news/2022-04-indigenous-good-forests.html">aided forest regeneration</a> didn’t help.</p>
<p>We are now in a unique situation where hot fires are creating their own weather — <a href="https://e360.yale.edu/features/fire-induced-storms-a-new-danger-from-the-rise-in-wildfires">fire-driven thunderstorms and pyrogenetic tornadoes</a> — that can spawn other fires. We saw this in Fort McMurray in 2016, in B.C. in the following years and in 2019 and 2020 when <a href="https://doi.org/10.1038/s41612-021-00192-9">Australia’s Black Summer fire season led to a massive outbreak of fire-induced and smoke-infused thunderstorms</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/YvfDbODi-vQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Wildfire-fuelled tornadoes have been witnessed across Canada, Australia and the U.S.</span></figcaption>
</figure>
<p>This is, in a word, scary.</p>
<p>The title of my book <em>Dark Days at Noon</em> harkens back to 1780 when smoke from distant fires blocked out so much sunlight that people from all over New England thought the end of the world was at hand. The end of the world is not at hand, but there will be many more dark days at noon if we do not learn to live with fire.</p><img src="https://counter.theconversation.com/content/190213/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edward Struzik does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The wildfires of the past were as fierce, deadly and eerily similar to the ones we have today. And we have yet to learn to live with them.Edward Struzik, Fellow, Queen's Institute for Energy and Environmental Policy, School of Policy Studies, Queen's University, OntarioLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1649162021-07-27T12:04:45Z2021-07-27T12:04:45ZSmall climate changes can have devastating local consequences – it happened in the Little Ice Age<figure><img src="https://images.theconversation.com/files/412943/original/file-20210723-25-p93203.jpg?ixlib=rb-1.1.0&rect=0%2C275%2C6819%2C4563&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Little Ice Age brought some bitter extremes.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Pieter_Bruegel_the_Elder_-_Hunters_in_the_Snow_(Winter)_-_Google_Art_Project.jpg">Pieter Bruegel the Elder, 1565</a></span></figcaption></figure><p>In recent weeks, <a href="https://www.nytimes.com/2021/07/16/world/europe/germany-floods-climate-change.html">catastrophic floods</a> overwhelmed towns in Germany, Belgium and the Netherlands, <a href="https://www.bbc.com/news/world-asia-china-57861067">inundated subway tunnels</a> in China, swept through northwestern Africa and triggered deadly landslides in <a href="https://www.cnn.com/2021/07/23/india/floods-landslides-maharashtra-intl-hnk/index.html">India</a> and <a href="https://www.bbc.com/news/world-asia-57704967">Japan</a>. Heat and drought fanned wildfires in the North American West and <a href="https://www.nytimes.com/2021/07/17/world/europe/siberia-fires.html">Siberia</a>, contributed to <a href="https://www.atlanticcouncil.org/blogs/iransource/iran-faces-its-driest-summer-in-fifty-years/">water shortages</a> in Iran, and <a href="https://www.nature.com/articles/d41586-020-02698-3">worsened famines</a> in Ethiopia, Somalia and Kenya. </p>
<p>Extremes like these are increasingly <a href="https://theconversation.com/is-climate-change-to-blame-for-the-recent-weather-disasters-2-things-you-need-to-understand-164919">caused or worsened by human activities heating up</a> Earth’s climate. For thousands of years, Earth’s climate has not changed <a href="https://nca2018.globalchange.gov/chapter/1/">anywhere near as quickly</a> or profoundly as it’s changing today. </p>
<p>Yet on a smaller scale, humans have seen waves of extreme weather events coincide with temperature changes before. It happened during what’s known as the Little Ice Age, a period between the 14th and 19th centuries that was marked by large volcanic eruptions and bitter cold spells in parts of the world.</p>
<p>The global average temperature is believed to have <a href="https://cp.copernicus.org/articles/15/1251/2019/">cooled</a> by less than a half-degree Celsius (less than 0.9 F) during even the chilliest decades of the Little Ice Age, but locally, extremes were common. </p>
<p>In diaries and letters from that period, people wrote about “<a href="https://www.wiley.com/en-us/Tambora+and+the+Year+without+a+Summer%3A+How+a+Volcano+Plunged+the+World+into+Crisis-p-9781509525492">years without a summer</a>,” when wintry weather persisted long after spring. <a href="https://press.princeton.edu/books/paperback/9780691168623/tambora">In one such summer</a>, in 1816, cold that followed a massive volcanic eruption in Indonesia ruined crops across parts of Europe and North America. Less well known are the unusually cold European summers of 1587, 1628 and 1675, when unseasonal frost provoked fear and, in some places, hunger.</p>
<p>“It is horribly cold,” author Marie de Rabutin-Chantal <a href="https://yalebooks.yale.edu/book/9780300219364/global-crisis">wrote</a> from Paris during the last of these years; “the behavior of the sun and of the seasons has changed.”</p>
<p>Winters could be equally terrifying. People reported 17th-century <a href="https://www.hup.harvard.edu/catalog.php?isbn=9780674971929">blizzards as far south as Florida</a> and the Chinese province of Fujian. <a href="https://www.cambridge.org/core/books/frigid-golden-age/FD88D1B4AFA571C02A33D34B65484928">Sea ice trapped</a> ships, repeatedly enclosed the Chesapeake Bay and <a href="https://yalebooks.yale.edu/book/9780300219364/global-crisis">froze over rivers</a> from the Bosporus to the Meuse. In early 1658, ice so completely covered the Baltic Sea that a Swedish army marched across the water separating Sweden and Denmark to besiege Copenhagen. Poems and songs suggest people simply froze to death while huddling in their homes.</p>
<p>These were cold snaps, not heat waves, but the overall story should seem familiar: A small global change in climate dramatically altered the likelihood of extreme local weather. Scholars who study the history of climate and society, <a href="https://www.dagomardegroot.com/">like me</a>, identify these changes in the past and find out how human populations responded. </p>
<h2>What’s behind the extremes</h2>
<p>We know about the Little Ice Age because the natural world is full of things like trees, stalagmites and ice sheets that <a href="https://jhupbooks.press.jhu.edu/title/tree-story">respond to weather</a> while growing or accumulating gradually over time. Specialists can use past fluctuations in their growth or chemistry as indicators of fluctuations in climate and thereby create <a href="https://www.palgrave.com/gp/book/9781137430199">graphs or maps – reconstructions</a> – that show historical climate changes. </p>
<p>These reconstructions reveal that <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/wcc.518">waves of cooling</a> swept across much of the world. They also suggest likely causes – including a series of explosive <a href="https://doi.org/10.1029/2011GL050168">volcanic</a> <a href="https://doi.org/10.1038/nature14565">eruptions</a> that abruptly released sunlight-scattering dust into the stratosphere; and slow, <a href="https://www.cambridge.org/core/books/frigid-golden-age/FD88D1B4AFA571C02A33D34B65484928">internal variability</a> in regional patterns of atmospheric and oceanic circulation.</p>
<p>These causes could only <a href="http://www.meteo.psu.edu/holocene/public_html/shared/articles/MannetalScience09.pdf">cool the Earth</a> by a few tenths of a degree Celsius during the chilliest waves of the Little Ice Age, however. And the cooling was <a href="https://doi.org/10.1038/s41561-019-0400-0">not nearly as consistent</a> as present-day warming. </p>
<p>Small global trends can mask far bigger local changes. Studies have suggested that modest cooling created by volcanic eruptions can <a href="https://doi.org/10.1175/JCLI-D-13-00524.1">reduce the usual contrast</a> between temperatures over land and sea, because land heats and cools faster than oceans. Since that contrast powers the monsoons, the African and East Asian summer monsoons <a href="https://doi.org/10.1038/ngeo2404">can weaken</a> after big eruptions. That likely disturbed atmospheric circulation all the way into the North Atlantic, reducing the flow of warm air into Europe. This is why parts of Western Europe, for example, may have cooled by more than 3 C (5.4 F) even as the rest of the world cooled far less during the 1816 year without a summer.</p>
<figure class="align-center ">
<img alt="Map showing the temperature anomaly, with Western Europe as much as 3 degrees colder than normal." src="https://images.theconversation.com/files/412992/original/file-20210725-27-199ry3f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412992/original/file-20210725-27-199ry3f.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=476&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412992/original/file-20210725-27-199ry3f.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=476&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412992/original/file-20210725-27-199ry3f.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=476&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412992/original/file-20210725-27-199ry3f.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=598&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412992/original/file-20210725-27-199ry3f.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=598&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412992/original/file-20210725-27-199ry3f.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=598&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Temperatures fell well below normal in parts of Europe in 1816.</span>
<span class="attribution"><span class="source">Dagomar Degroot</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Feedback loops also <a href="https://doi.org/10.1002/wcc.518">amplified and sustained regional cooling</a>, similar to how they <a href="https://doi.org/10.1038/s43247-020-00077-4">amplify</a> regional <a href="https://doi.org/10.1088/1748-9326/aab827">warming</a> today. In the Arctic, for example, cooler temperatures can mean more, longer-lasting sea ice. Ice reflects more sunlight back into space than water does, and that feedback loop leads to more cooling, more ice and so on. As a result, the comparatively modest climate changes of the Little Ice Age likely had profound local impacts.</p>
<p>Changing patterns of atmospheric circulation and pressure also led in many regions to remarkably wet, dry or stormy weather.</p>
<p>Heavy sea ice in the Greenland Sea may have diverted the North Atlantic storm track south, funneling severe gales toward the dikes and dams of what are today the Netherlands and Belgium. Thousands of people succumbed in the <a href="https://doi.org/10.1093/pastj/gty018">1570 All Saints’ Day Flood</a> along the German and Dutch coast, and again in the <a href="https://doi.org/10.1093/envhis/emv002">Christmas Flood of 1717</a>. Heavy precipitation and water pooling behind dams of melting ice repeatedly overwhelmed inadequate flood defenses and inundated central and Western Europe. “Who would not take pity on the city?” <a href="https://www.cambridge.org/core/books/frigid-golden-age/FD88D1B4AFA571C02A33D34B65484928">one chronicler lamented</a> after seeing his town under water and then on fire in 1602. “One storm, one flood, one fire destroyed it all.”</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/412993/original/file-20210725-17-1od6tvq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412993/original/file-20210725-17-1od6tvq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412993/original/file-20210725-17-1od6tvq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412993/original/file-20210725-17-1od6tvq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412993/original/file-20210725-17-1od6tvq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412993/original/file-20210725-17-1od6tvq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412993/original/file-20210725-17-1od6tvq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Disastrous storms, like one in 1775 in the Netherlands, were documented by engravers and other artists.</span>
<span class="attribution"><a class="source" href="https://www.rijksmuseum.nl/en/collection/RP-P-OB-84.965">Noach van der Meer II, after Hendrik Kobell</a></span>
</figcaption>
</figure>
<p>Cooling sea surface temperatures in the North Atlantic Ocean probably also <a href="https://doi.org/10.1029/2009GL038677">diverted the rain-giving winds</a> around the equator <a href="https://doi.org/10.1038/ngeo554">to the south</a>, provoking droughts that <a href="https://doi.org/10.1073/pnas.0910827107">undermined the water infrastructure</a> of 15th-century Angkor.</p>
<p>Owing perhaps to the modest cooling of volcanic dust veils, disrupted patterns of atmospheric circulation led in the 16th century to severe droughts that contributed to <a href="https://www.cambridge.org/core/books/climate-of-rebellion-in-the-early-modern-ottoman-empire/C022031EDC39F862EA87DBC88D66B888">food shortages</a> across the Ottoman Empire. In 1640, the grand canal that supplied Beijing with food simply <a href="https://doi.org/10.1007/s10584-007-9283-y">dried up</a>, and a short but <a href="https://doi.org/10.1126/sciadv.1500561">profound drought</a> in 1666 <a href="https://www.cambridge.org/core/books/frigid-golden-age/FD88D1B4AFA571C02A33D34B65484928">primed the wooden infrastructure</a> of European cities for a wave of catastrophic urban fires. </p>
<h2>How does it apply to today?</h2>
<p>Today, the temperature shift is going in the other direction – with global temperatures already <a href="https://climate.nasa.gov/vital-signs/carbon-dioxide/">1 C (1.8 F) higher</a> than before the industrial era, and local, sometimes devastating, extremes occurring around the world.</p>
<p>New research has found that extreme heat waves, those that don’t just break records but shatter them, become <a href="https://doi.org/10.1038/s41558-021-01092-9">more common when temperatures change rapidly</a>.</p>
<p>These serve as a warning to governments to redouble their efforts to <a href="https://www.ipcc.ch/sr15/">limit warming</a> to 1.5 C (2.7 F), relative to the 20th-century average, while also investing in the development and <a href="https://www.carbonbrief.org/explainer-10-ways-negative-emissions-could-slow-climate-change">deployment</a> of technologies that filter greenhouse gases out of the atmosphere.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/412994/original/file-20210725-14570-1vwpd07.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A visualization of temperature change as colored stripes" src="https://images.theconversation.com/files/412994/original/file-20210725-14570-1vwpd07.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/412994/original/file-20210725-14570-1vwpd07.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=262&fit=crop&dpr=1 600w, https://images.theconversation.com/files/412994/original/file-20210725-14570-1vwpd07.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=262&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/412994/original/file-20210725-14570-1vwpd07.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=262&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/412994/original/file-20210725-14570-1vwpd07.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=330&fit=crop&dpr=1 754w, https://images.theconversation.com/files/412994/original/file-20210725-14570-1vwpd07.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=330&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/412994/original/file-20210725-14570-1vwpd07.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=330&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Visualizing temperature anomalies over 2,000 years, with colder temperatures in darker blues and hotter temperatures in darker reds, shows the chilly periods of the Little Ice Age and the extreme warming of today.</span>
<span class="attribution"><span class="source">Ed Hawkins</span></span>
</figcaption>
</figure>
<p>Restoring the chemistry of the atmosphere will still take many decades after countries bring down their greenhouse gas emissions, and so <a href="https://www.nytimes.com/2021/07/21/opinion/climate-change-heat-waves.html">communities must adapt</a> to a hotter and less habitable planet. Nations and
communities might learn from some of the success stories of the Little Ice Age: Populations that <a href="https://www.nature.com/articles/s41586-021-03190-2">prospered</a> were often those that <a href="https://www.hf.uio.no/iakh/english/research/news-and-events/news/2020/equality-has-always-been-the-best-remedy">provided for their poor</a>, established diverse trade networks, <a href="https://www.cambridge.org/core/books/frigid-golden-age/FD88D1B4AFA571C02A33D34B65484928">migrated from vulnerable environments</a>, and above all <a href="https://doi.org/10.1177/0959683616646188">adapted proactively to new environmental realities</a>. </p>
<p>People who lived through the Little Ice Age lacked perhaps the most important resource available today: the ability to learn from the long global history of human responses to climate change. </p>
<p>[<em>Get our best science and technology stories.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-best">Sign up for The Conversation’s science newsletter</a>.]</p><img src="https://counter.theconversation.com/content/164916/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dagomar Degroot does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Globally, the temperature changed by half a degree Celsius, but it dramatically altered the likelihood of extreme local weather.Dagomar Degroot, Associate Professor of Environmental History, Georgetown UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1606142021-06-01T04:17:48Z2021-06-01T04:17:48ZClimate explained: why is the Arctic warming faster than other parts of the world?<figure><img src="https://images.theconversation.com/files/403487/original/file-20210531-21-14snmdk.jpg?ixlib=rb-1.1.0&rect=29%2C65%2C3956%2C2778&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock/Michal Balada</span></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
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<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p><em><strong><a href="https://theconversation.com/nz/topics/climate-explained-74664">Climate Explained</a></strong> is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.</em> </p>
<p><em>If you have a question you’d like an expert to answer, please send it to <a href="mailto:climate.change@stuff.co.nz">climate.change@stuff.co.nz</a></em></p>
<hr>
<blockquote>
<p><strong>What is Arctic amplification? Do we know what is causing this phenomenon? What effects is it having, both in the region and for the world? Is Antarctica experiencing the same thing?</strong></p>
</blockquote>
<p>Human civilisation and agriculture first emerged about 12,000 years ago in the early <a href="https://australian.museum/learn/australia-over-time/evolving-landscape/the-holocene-epoch/">Holocene</a>. Our ancestors benefited from a remarkably stable climate during this time as <a href="https://www.co2.earth/co2-ice-core-data">carbon dioxide levels in the atmosphere</a> remained near 280ppm until the beginning of the industrial revolution in the 1800s. </p>
<p>Prior to the 1800s, the balance between incoming and outgoing energy (radiation) at the top of the atmosphere (<a href="https://climate.nasa.gov/faq/19/what-is-the-greenhouse-effect/">the greenhouse effect</a>) maintained global average temperatures for many centuries. Only small changes in <a href="https://climate.nasa.gov/blog/2910/what-is-the-suns-role-in-climate-change/">solar output</a> and occasional <a href="https://www.usgs.gov/natural-hazards/volcano-hazards/volcanoes-can-affect-climate">volcanic eruptions</a> caused periods of relative warming and cooling. For example, the <a href="https://www.eh-resources.org/timeline-middle-ages/">Little Ice Age</a> was a cooler period between 1300 and 1870. </p>
<p>Today carbon dioxide levels are <a href="https://www.co2.earth">near 420ppm</a> and all <a href="https://climate.nasa.gov/causes/">greenhouse gases are rising rapidly</a> due to the burning of fossil fuels, industrial processes, tropical forest destruction, landfills and agriculture. The global average temperature has increased by a little more than 1°C since 1900. </p>
<p>This figure seems small, but the <a href="https://www.climate.gov/news-features/featured-images/2020-arctic-air-temperatures-continue-long-term-warming-streak">Arctic region</a> has warmed by about 2°C in this time — twice as fast. </p>
<p>This warming differential between the poles and the tropics is known as Arctic (or polar) <a href="https://nsidc.org/cryosphere/arctic-meteorology/climate_change.html">amplification</a>. </p>
<figure class="align-center ">
<img alt="A map showing which parts of the world are warming faster than others." src="https://images.theconversation.com/files/403483/original/file-20210531-13-1s7dy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403483/original/file-20210531-13-1s7dy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403483/original/file-20210531-13-1s7dy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403483/original/file-20210531-13-1s7dy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403483/original/file-20210531-13-1s7dy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403483/original/file-20210531-13-1s7dy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403483/original/file-20210531-13-1s7dy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Arctic region is warming faster than other parts of the globe.</span>
<span class="attribution"><a class="source" href="http://berkeleyearth.org/">Berkeley Earth</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>It occurs whenever there is any change in the <a href="https://earthobservatory.nasa.gov/global-maps/CERES_NETFLUX_M">net radiation balance</a> of Earth, and this produces a larger change in temperature near the poles than the global average. It is typically measured as the ratio of polar warming to tropical warming.</p>
<h2>Melting ice</h2>
<p>So how is climate change and associated global heating driving Arctic amplification? This amplification is primarily caused by melting ice — a process that is <a href="https://climate.nasa.gov/vital-signs/arctic-sea-ice/">increasing in the Arctic</a> at a rate of 13% per decade. </p>
<p>Ice is more reflective and less absorbent of sunlight than land or the surface of an ocean. When ice melts, it typically reveals darker areas of land or sea, and this results in increased sunlight absorption and associated warming.</p>
<p>Polar amplification is much <a href="https://esd.copernicus.org/articles/8/323/2017/">stronger in the Arctic</a> than in Antarctica. This difference is because the Arctic is an ocean covered by sea ice, while Antarctica is an elevated continent covered in more permanent ice and snow. </p>
<p>In fact, the <a href="https://www.nature.com/articles/s41612-020-00143-w">Antarctic continent has not warmed</a> in the past seven decades, despite a steady increase in the atmospheric concentrations of greenhouse gases. </p>
<p>The exception is the Antarctic peninsula, which juts out further north into the Southern Ocean and has been <a href="https://www.frontiersin.org/articles/10.3389/fenvs.2019.00102/full">warming faster</a> than any other terrestrial environment in the southern hemisphere during the latter half of the 20th century. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/if-warming-exceeds-2-c-antarcticas-melting-ice-sheets-could-raise-seas-20-metres-in-coming-centuries-124484">If warming exceeds 2°C, Antarctica's melting ice sheets could raise seas 20 metres in coming centuries</a>
</strong>
</em>
</p>
<hr>
<p>Satellite data also show that between 2002 and 2020, Antarctica <a href="https://climate.nasa.gov/climate_resources/265/video-antarctic-ice-mass-loss-2002-2020/">lost an average of 149 billion metric tonnes of ice</a> per year, partly because the oceans around the continent are warming. </p>
<h2>Effects of Arctic warming</h2>
<p>One of the most significant effects of Arctic amplification is the <a href="https://sos.noaa.gov/datasets/earthnow-how-does-the-arctic-affect-extreme-weather/">weakening of west-to-east jet streams</a> in the northern hemisphere. As the Arctic warms at a faster rate than the tropics, this results in a weaker atmospheric <a href="https://link.springer.com/referenceworkentry/10.1007%2F0-387-30749-4_144">pressure gradient</a> and hence lower wind speeds.</p>
<p>The links between Arctic amplification, slowing (or meandering) jet streams, <a href="https://www.sciencedaily.com/releases/2019/11/191113075107.htm">blocking highs</a> and extreme weather events in the mid to high latitudes of the northern hemisphere is controversial. One view is that the <a href="https://www.nature.com/articles/s41467-018-05256-8">link is strong</a> and the major driver behind recent severe <a href="https://arstechnica.com/science/2019/12/heatwaves-on-multiple-continents-linked-by-jet-stream-tendency/">summer heat waves</a> and <a href="https://insideclimatenews.org/news/02022018/cold-weather-polar-vortex-jet-stream-explained-global-warming-arctic-ice-climate-change/">winter cold waves</a>. But more <a href="https://advances.sciencemag.org/content/6/8/eaay2880">recent research</a> questions the validity of these links for the mid latitudes. </p>
<p>Here we look at the larger body of evidence that supports the relationship between Arctic warming and slowing jet streams.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/siberia-heatwave-why-the-arctic-is-warming-so-much-faster-than-the-rest-of-the-world-141455">Siberia heatwave: why the Arctic is warming so much faster than the rest of the world</a>
</strong>
</em>
</p>
<hr>
<p>The Arctic is warming much faster than the rest of the planet and the loss of reflective ice contributes somewhere between 30-50% of Earth’s global heating. This rapid loss of ice affects the polar jet stream, a concentrated pathway of air in the upper atmosphere which drives the weather patterns across the northern hemisphere. </p>
<p>The weakened jet stream meanders and brings the polar vortex further south, which results in <a href="https://medium.com/@lauren_58899/its-a-small-world-after-all-the-connection-between-arctic-ice-loss-and-tropical-zones-5034272db8c6">extreme weather events</a> in North America, Europe and Asia.</p>
<figure class="align-center ">
<img alt="Graphic explaing the polar vortex" src="https://images.theconversation.com/files/403482/original/file-20210531-21-z9h9ab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403482/original/file-20210531-21-z9h9ab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=381&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403482/original/file-20210531-21-z9h9ab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=381&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403482/original/file-20210531-21-z9h9ab.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=381&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403482/original/file-20210531-21-z9h9ab.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=479&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403482/original/file-20210531-21-z9h9ab.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=479&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403482/original/file-20210531-21-z9h9ab.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=479&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
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<span class="attribution"><span class="source">NOAA</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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</figure>
<p>So what are the future prospects for Australia and Aotearoa/New Zealand? Global climate models project stronger surface warming in <a href="https://atmos.washington.edu/%7Edavid/Hahn_etal_2020.pdf">the Arctic than the Antarctic</a> under climate change. Given that temperatures above the Antarctic continent have remained stable for over 70 years despite the rise in greenhouse gases, we might expect little change for our region — just normal climatic variability due to other climate drivers like the <a href="https://niwa.co.nz/climate/information-and-resources/elnino">El Niño-Southern Oscillation</a>, the <a href="http://www.bom.gov.au/climate/enso/history/ln-2010-12/SAM-what.shtml">Southern Annular Mode</a>, and the <a href="http://www.bom.gov.au/climate/iod/">Indian Ocean Dipole</a>. </p>
<p>But as the tropics continue to <a href="https://theconversation.com/the-worlds-tropical-zone-is-expanding-and-australia-should-be-worried-77701">warm and expand</a>, we may expect an increase in the pressure gradient between the tropics and Antarctica that will lead to increased <a href="https://www.sciencedaily.com/releases/2020/12/201209094229.htm">circumpolar westerlies winds</a>.</p>
<p>The recent intensification and more poleward location of the southern hemisphere belt of <a href="https://www.nature.com/articles/s43247-020-00059-6">westerly winds</a> have been linked to continental droughts and wildfires, including those in Australia. We can also expect strengthening westerlies to affect mixing in the Southern Ocean, which could reduce its capacity to take up carbon dioxide and enhance the ocean-driven melting of ice shelves fringing the West Antarctic Ice Sheet. </p>
<p>These changes in turn have far-reaching implications for global ocean circulation and sea level rise.</p><img src="https://counter.theconversation.com/content/160614/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Steve Turton has received funding from the Australian Government. </span></em></p>The Arctic region is warming much faster than the rest of the planet. The rapid loss of ice affects the polar jet stream, which influences weather patterns across the northern hemisphere.Steve Turton, Adjunct Professor of Environmental Geography, CQUniversity AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1450432020-09-22T19:58:35Z2020-09-22T19:58:35ZClimate explained: humans have dealt with plenty of climate variability<figure><img src="https://images.theconversation.com/files/356872/original/file-20200908-14-ggdzgl.jpg?ixlib=rb-1.1.0&rect=12%2C187%2C4013%2C2830&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Professor John Long, Flinders University</span>, <span class="license">Author provided</span></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/287622/original/file-20190811-144878-bvgm9l.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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</figure>
<p><em><strong><a href="https://theconversation.com/nz/topics/climate-explained-74664">Climate Explained</a></strong> is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.</em> </p>
<p><em>If you have a question you’d like an expert to answer, please send it to <a href="mailto:climate.change@stuff.co.nz">climate.change@stuff.co.nz</a></em></p>
<hr>
<blockquote>
<p><strong>How much climate variability have humans dealt with since we evolved and since we started settling (Neolithic times)? How important was migration to human survival during these periods?</strong></p>
</blockquote>
<p>The climate always fluctuates as variation in the Sun’s heat reaching Earth drives <a href="https://climate.nasa.gov/news/2948/milankovitch-orbital-cycles-and-their-role-in-earths-climate/">glacial-interglacial cycles</a>. Over the past 420,000 years there have been at least four major transitions between ice ages and relatively warmer interglacial periods. </p>
<p>Modern humans <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/evan.21455" title="Rethinking the dispersal of Homo sapiens out of Africa">emigrated from Africa</a> to populate the rest of the globe between 120,000 and 80,000 years ago, which means our species has had to adapt to many massive climate transitions. </p>
<h2>Warming and cooling</h2>
<p>The <a href="https://www.ncdc.noaa.gov/global-warming/penultimate-interglacial-period">Last Interglacial</a> 129,000–116,000 years ago was a period of intense global warming (from around 2°C higher than today to as much as <a href="https://science.sciencemag.org/content/355/6322/276" title="Regional and global sea-surface temperatures during the last interglaciation">11°C higher in the Arctic</a>), leading to a large reduction of the Arctic, Greenland and Antarctic ice sheets, and <a href="https://science.sciencemag.org/content/349/6244/aaa4019" title="Sea-level rise due to polar ice-sheet mass loss during past warm periods">a 6–9m rise in sea level</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/358287/original/file-20200916-22-1ahavm0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The front of a glacier breaking away and falling into the sea." src="https://images.theconversation.com/files/358287/original/file-20200916-22-1ahavm0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/358287/original/file-20200916-22-1ahavm0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/358287/original/file-20200916-22-1ahavm0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/358287/original/file-20200916-22-1ahavm0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/358287/original/file-20200916-22-1ahavm0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/358287/original/file-20200916-22-1ahavm0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/358287/original/file-20200916-22-1ahavm0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Arctic glaciers have melted before.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/kimberlykv/5001061623/">Flickr/Kimberly Vardeman</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The <a href="https://theconversation.com/the-last-ice-age-tells-us-why-we-need-to-care-about-a-2-change-in-temperature-126923">Last Glacial Maximum</a> from 26,500–19,000 years ago coincided with a large drop in atmospheric CO₂ and a 4.3°C cooling globally.</p>
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Read more:
<a href="https://theconversation.com/climate-explained-will-the-tropics-eventually-become-uninhabitable-145174">Climate explained: will the tropics eventually become uninhabitable?</a>
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<p>Low temperatures turned much of the world’s water into ice and expanded glaciers.</p>
<p>This lowered sea level by <a href="https://doi.org/10.1038/35021035" title="Timing of the Last Glacial Maximum from observed sea-level minima">up to 130m</a> compared to today. This exposed continental shelves, joined land masses and created extensive coastal plains, such as <a href="https://www.nps.gov/bela/learn/beringia.htm">Beringia</a> that connected Russia to North America, and <a href="https://www.thoughtco.com/sahul-pleistocene-continent-172704">Sahul</a> that connected Australia to New Guinea. </p>
<p>After a brief warming period, the Northern Hemisphere returned abruptly to near-glacial conditions around 12,900 years ago that lasted 1,300 years. Known as the <a href="https://www.ncdc.noaa.gov/abrupt-climate-change/The%20Younger%20Dryas">Younger Dryas</a>, this period recorded climate cooling up to 15°C and <a href="https://www.nature.com/articles/34346" title="Timing of abrupt climate change at the end of the Younger Dryas interval from thermally fractionated gases in polar ice">giant ice sheets again advanced</a>. The end of the Younger Dryas was just as sudden, marked by a rapid warming up to 10°C in few decades.</p>
<p>The most recent period of climate instability was the transition from the <a href="https://science.sciencemag.org/content/326/5957/1256" title="Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly">Medieval Warm Period to the Little Ice Age</a>. Cold conditions between <a href="https://www.nature.com/articles/ngeo1797" title="Continental-scale temperature variability during the past two millennia">1580 and 1880</a> were characterised by a 0.5–4°C <a href="https://science.sciencemag.org/content/274/5292/1504" title="The Little Ice Age and Medieval Warm Period in the Sargasso Sea">cooling</a> and <a href="https://www.geo.umass.edu/climate/papers2/Matthews_05.pdf">expanding mountain glaciers</a> in the European Alps, New Zealand, Alaska and the Andes.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/358295/original/file-20200916-24-6gbt5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An oil painting showing a winter landscape with many people ice skating." src="https://images.theconversation.com/files/358295/original/file-20200916-24-6gbt5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/358295/original/file-20200916-24-6gbt5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=347&fit=crop&dpr=1 600w, https://images.theconversation.com/files/358295/original/file-20200916-24-6gbt5a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=347&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/358295/original/file-20200916-24-6gbt5a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=347&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/358295/original/file-20200916-24-6gbt5a.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=436&fit=crop&dpr=1 754w, https://images.theconversation.com/files/358295/original/file-20200916-24-6gbt5a.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=436&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/358295/original/file-20200916-24-6gbt5a.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=436&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Winter Landscape with Skaters by Hendrick Avercamp in 1608 is one of many artworks that depict the cold winter weather during the Little Ice Age.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/File:Hendrick_Avercamp_-_Winterlandschap_met_ijsvermaak.jpg">Wikimedia/Rijksmuseum Amsterdam</a></span>
</figcaption>
</figure>
<h2>What climate change meant for humans</h2>
<p>Despite our impressive capacity to adapt to a broad range of environments, humans have a <a href="https://global.oup.com/academic/product/the-improbable-primate-9780199658794" title="The Improbable Primate">preferred environmental envelope</a> in which we thrive. These conditions would have been characterised by a mix of <a href="https://www.sciencedirect.com/science/article/pii/S1040618213001730" title="The Water Optimisation Hypothesis and the human occupation of the mid-latitude belt in the Pleistocene">open, savanna-type woodlands, wetlands and rocky habitats</a>.</p>
<p>Dense, humid rain forests made access to resources difficult, whereas deserts were often too dry to provide enough food and materials. </p>
<p>Climate conditions during the Last Interglacial could have <a href="https://www.nature.com/articles/nature19365" title="Late Pleistocene climate drivers of early human migration">encouraged waves of human expansion</a> out of Africa when a humid and warm climate promoted vegetated corridors through Eurasia. </p>
<p>The subsequent cooling period connected land masses that had previously been separated by oceans and provided opportunities for human travellers to access Sahul from the Indonesian archipelago.</p>
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Read more:
<a href="https://theconversation.com/an-incredible-journey-the-first-people-to-arrive-in-australia-came-in-large-numbers-and-on-purpose-114074">An incredible journey: the first people to arrive in Australia came in large numbers, and on purpose</a>
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<p>The entrance into America from Asia via Beringia was more difficult because humans only reached there during the Last Glacial Maximum when a massive ice sheet blocked the new land bridge. </p>
<p>During that time, human populations <a href="https://www.pnas.org/content/112/27/8232" title="Human population dynamics in Europe over the Last Glacial Maximum">declined</a> and contracted to <a href="https://science.sciencemag.org/content/335/6074/1317" title="Human Evolution Out of Africa: The Role of Refugia and Climate Change">small refuges</a> until the climate in eastern Beringia began to warm again 17,000–15,000 years ago.</p>
<p>This warming created newly accessible pathways along the Pacific Northwest coast, followed by another ice-free corridor that formed 3,000 years later as the ice sheet retreated. </p>
<h2>The need for food</h2>
<p>Because of the cold temperatures and scarcity of food at this time, humans needed to improve their hunting efficiency by targeting large animals to maximise food return. </p>
<p>In the Southern Hemisphere, modern humans had already been living in Australia for 30,000–40,000 years prior to the Last Glacial Maximum, so such drastic cooling and drying probably pushed <a href="https://www.sciencedirect.com/science/article/pii/S0277379117305267" title="Sea-level change and demography during the last glacial termination and early Holocene across the Australian continent">human populations to decline and retreat into smaller refuges</a> nearer to reliable sources of fresh water where game animals also gathered.</p>
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<strong>
Read more:
<a href="https://theconversation.com/did-people-or-climate-kill-off-the-megafauna-actually-it-was-both-127803">Did people or climate kill off the megafauna? Actually, it was both</a>
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<p>Following the Last Glacial Maximum, modern humans continued to spread across North America. The warmer and wetter climate in the Southern Hemisphere also helped <a href="https://www.sciencedirect.com/science/article/pii/S0012821X10001512" title="Abrupt Younger Dryas cooling in the northern tropics recorded in lake sediments from the Venezuelan Andes">human migration into South America</a>.</p>
<p>At the same time the Younger Dryas in the Northern Hemisphere forced populations either to return to a nomadic lifestyle or seek refuge in a few hospitable areas. After the harsh conditions of the Younger Dryas, the <a href="https://www.nature.com/articles/nature07895" title="The nature of selection during plant domestication">first evidence of agriculture</a> emerged in various parts of the world. </p>
<p>The peopling of remote Oceania between 3,500 and 730 years ago required oceanic journeys of thousands of kilometres across the Pacific, eventually to the <a href="https://link.springer.com/article/10.1007/s10963-017-9110-y" title="Mass Migration and the Polynesian Settlement of New Zealand">temperate and subantarctic waters of New Zealand</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/358304/original/file-20200916-16-1wabnex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A warm sunrise on the New Zealand coast" src="https://images.theconversation.com/files/358304/original/file-20200916-16-1wabnex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/358304/original/file-20200916-16-1wabnex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/358304/original/file-20200916-16-1wabnex.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/358304/original/file-20200916-16-1wabnex.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/358304/original/file-20200916-16-1wabnex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/358304/original/file-20200916-16-1wabnex.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/358304/original/file-20200916-16-1wabnex.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A warming planet created conditions that helped migration across Oceania including to New Zealand.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/domenjakus/6319218781/">Flickr/Domen Jakus</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>Although these migrations are not clearly related to any of the earlier climate-change events, the wind patterns at the time were particularly <a href="https://www.pnas.org/content/111/41/14716" title="Climate windows for Polynesian voyaging to New Zealand and Easter Island">favourable for sailing</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/climate-explained-sunspots-do-affect-our-weather-a-bit-but-not-as-much-as-other-things-145101">Climate explained: Sunspots do affect our weather, a bit, but not as much as other things</a>
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</p>
<hr>
<p>But the Little Ice Age could have reduced population size and <a href="https://journals.sagepub.com/doi/10.1177/0959683618761545" title="Two-step human–environmental impact history for northern New Zealand linked to late-Holocene climate change">pushed early Māori settlement northward</a>. </p>
<p>The Little Ice age probably hit people in the Northern Hemisphere much harder. The cold climate caused widespread <a href="https://www.hachette.com.au/brian-fagan/the-little-ice-age-how-climate-made-history-1300-1850">crop failures, famines and population declines</a>. </p>
<p>During the last five years alone, the Earth is already <a href="http://www.columbia.edu/%7Emhs119/Temperature/Emails/July2018.pdf">~1.1°C warmer than 150 years ago</a> and temperatures are expected to be <a href="https://www.wcrp-climate.org/wgcm-cmip/wgcm-cmip5">+4.5°C warmer than today by 2100</a>. Today we are experiencing the warmest climate since our species started peopling the globe. </p>
<p>Climate fluctuations that used to take millennia are now occurring in less than 100 years, affecting <a href="https://www.noaa.gov/education/resource-collections/climate/climate-change-impacts">fresh water availability, food supply, health, and environmental integrity</a>. </p>
<p>Past climate changes set the stage for people to demonstrate immense <a href="https://cp.copernicus.org/articles/14/1487/2018/cp-14-1487-2018.html" title="Vulnerability, resilience and adaptation of societies during major extreme storms during the Little Ice Age">adaptability and resilience</a> by developing new skills, farming techniques, trading patterns and political structures, but most importantly by leaving their old, unsustainable ways of life behind.</p><img src="https://counter.theconversation.com/content/145043/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Frédérik Saltré receives funding from the Australian Research Council</span></em></p><p class="fine-print"><em><span>Corey J. A. Bradshaw receives funding from the Australian Research Council. </span></em></p>We have had to adapt to several changes to our climate since we started our migration out of Africa many thousands of years ago.Frédérik Saltré, Research Fellow in Ecology & Associate Investigator for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders UniversityCorey J. A. Bradshaw, Matthew Flinders Fellow in Global Ecology and Models Theme Leader for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/821042017-09-08T00:18:35Z2017-09-08T00:18:35ZHow fashion adapted to climate change – in the Little Ice Age<figure><img src="https://images.theconversation.com/files/185176/original/file-20170907-9599-1hmvfjb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hendrick Avercamp's 'Ice Scene' (c. 1610).</span> <span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/5/54/Hendrick_Avercamp_-_The_Pleasures_of_Winter.jpg">Wikimedia Commons</a></span></figcaption></figure><p>One could say the consequences of the planet’s warming climate can be seen on fashion week runways and the shelves of Anthropologie and H&M. Silhouettes shrink as midriffs and backs open. Sheer fabrics, breathable textiles and flowy draping <a href="http://www.cosmopolitan.com/style-beauty/fashion/advice/a41303/summer-style-tricks-to-keep-you-cool/">are in</a>. And in response to climate change’s rapid pace, some corners of the fashion industry are moving toward implementing <a href="http://eco-age.com/green-carpet-challenge/">sustainable business practices</a> and incorporating <a href="http://www.independent.co.uk/life-style/fashion/climate-change-forces-fashion-students-to-study-the-weather-a7445361.html">more flexibility</a> within their <a href="http://www.latimes.com/science/sciencenow/la-sci-sn-cool-shirt-20160901-snap-story.html">designs</a>. </p>
<p>Today people may see global warming as a modern phenomenon, but fashion has a long history of responding to worldwide climate change. </p>
<p>The only difference is that while we sweat, early modern Europeans froze. The Little Ice Age was an interval of erratic cooling that ravaged the Northern Hemisphere roughly between the 14th and 19th centuries. And like today’s designers, Renaissance fashion designers were forced to contend with shifting temperatures and strange weather.</p>
<h2>A menacing chill settles on Europe</h2>
<p>Scientists have yet to determine the primary cause of the <a href="http://earthsky.org/earth/volcanoes-might-have-triggered-the-little-ice-age">Little Ice Age</a>, and historians are still pinning down its exact chronological parameters. But voices from the era describe a rapidly cooling climate.</p>
<p>“At this time there was such a great cold that we almost froze to death in our quarters,” a soldier <a href="https://yalebooks.yale.edu/book/9780300208634/global-crisis">wrote in his diary</a> while traveling through Germany in 1640. “And,” he continued, “on the road, three people did freeze to death: a cavalry-man, a woman, and a boy.”</p>
<p>The entry was from August. </p>
<p>Scholars do agree that the Little Ice Age <a href="https://books.google.com/books/about/The_Little_Ice_Age.html?id=LwvkmXt5fQUC">impacted our shared global history</a> in myriad traceable ways. Its unpredictable temperature fluctuations and sudden freezes devastated harvests, escalated civil unrest and left thousands to starve. It may have inspired the menacingly chilly settings of Shakespeare’s “King Lear” and Charles Dickens’s “A Christmas Carol.” Darkness and clouds <a href="http://onlinelibrary.wiley.com/doi/10.1002/j.1477-8696.1970.tb03232.x/abstract">haunt the skies</a> of <a href="https://commons.wikimedia.org/wiki/File:Pieter_Bruegel_the_Elder_-_Hunters_in_the_Snow_(Winter)_-_Google_Art_Project.jpg">paintings</a> created during the period. </p>
<p>And the Little Ice Age also <a href="http://www.madamegilflurt.com/2015/09/the-little-ice-age-and-fashion.html">altered the history of fashion</a>. As the cold ramped up in the 16th century, fashion championed warmer styles: Heavy drapery, multiple layers and sleeves that trailed on the floor became more common across the visual and material record, while examples of the oldest surviving European <a href="http://www.metmuseum.org/art/collection/search/119576?sortBy=Relevance&amp;deptids=8&amp;when=A.D.+1400-1600&amp;ft=gloves&amp;offset=0&amp;rpp=20&amp;pos=1">gloves</a>, <a href="http://www.metmuseum.org/art/collection/search/84052?sortBy=Relevance&amp;deptids=8&amp;when=A.D.+1400-1600&amp;ft=*&amp;offset=40&amp;rpp=20&amp;pos=46">hats</a>, <a href="http://www.metmuseum.org/art/collection/search/79091">capes</a> and <a href="http://www.metmuseum.org/art/collection/search/85059?sortBy=Relevance&amp;deptids=8&amp;when=A.D.+1400-1600&amp;ft=*&amp;offset=20&amp;rpp=20&amp;pos=34">coats</a> from the era populate museum costume collections today. </p>
<p>“No one in Egypt used to know about wearing furs,” a Turkish man traveling through northern Africa <a href="https://yalebooks.yale.edu/book/9780300208634/global-crisis">wrote in 1670</a>. “There was no winter. But now we have severe winters and we have started wearing furs because of the cold.”</p>
<h2>Staying fashionably warm</h2>
<p>This change can be observed by comparing medieval and Renaissance dress.</p>
<p><a href="https://commons.wikimedia.org/wiki/File:Moralia_in_Job_MS_dragonslayer.jpg">In one French medieval manuscript</a> (illustrated between 1115 and 1125), the knight’s skirt is slit to the hip, and his squire’s hemline stops above the knee. There are no capes, fur or headgear; the garments are light and loose – especially compared to what men wore 400 years later, when the Little Ice Age was in full swing.</p>
<p>Take Hans Holbien’s iconic 1553 painting “<a href="https://commons.wikimedia.org/wiki/File:Hans_Holbein_the_Younger_-_The_Ambassadors_-_Google_Art_Project.jpg">The French Ambassadors</a>,” which depicts two courtiers to King Henry VIII. The man on the left, wearing thick, dark velvets and a heavily fur-lined overcoat, is the French ambassador to England, Jean de Dinteville. Georges de Selve, the bishop of Lavaur, stands on the right. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/185174/original/file-20170907-9603-1t92oi7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/185174/original/file-20170907-9603-1t92oi7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/185174/original/file-20170907-9603-1t92oi7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=520&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185174/original/file-20170907-9603-1t92oi7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=520&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185174/original/file-20170907-9603-1t92oi7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=520&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185174/original/file-20170907-9603-1t92oi7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=653&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185174/original/file-20170907-9603-1t92oi7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=653&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185174/original/file-20170907-9603-1t92oi7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=653&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hans Holbein’s ‘The Ambassadors.’</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/thumb/8/88/Hans_Holbein_the_Younger_-_The_Ambassadors_-_Google_Art_Project.jpg/1039px-Hans_Holbein_the_Younger_-_The_Ambassadors_-_Google_Art_Project.jpg">Wikimedia Commons</a></span>
</figcaption>
</figure>
<p>The cleric has donned a floor-length coat befitting his godly station. But it would have also been very effective against cold. Both men sport fashionable caps and undergarments. The laced collar of De Selve’s undershirt peaks above his robes, and those white slashes in de Dinteville shiny pink shirt show off his hidden layers. </p>
<p>As with all portraits from the era, these men dressed to impress for the sitting – meaning their fanciest clothes were possibly their warmest.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/185170/original/file-20170907-9568-17z0fee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/185170/original/file-20170907-9568-17z0fee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/185170/original/file-20170907-9568-17z0fee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1098&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185170/original/file-20170907-9568-17z0fee.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1098&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185170/original/file-20170907-9568-17z0fee.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1098&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185170/original/file-20170907-9568-17z0fee.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185170/original/file-20170907-9568-17z0fee.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185170/original/file-20170907-9568-17z0fee.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1380&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A c. 1545 portrait of Catherine Parr.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/5/53/Catherine_Parr.jpg">Wikimedia Commons</a></span>
</figcaption>
</figure>
<p>Women’s clothing also had to sustain temperature fluctuations that tended to range colder during the Little Ice Age. In a 16th-century <a href="https://commons.wikimedia.org/wiki/File:Catherine_Parr.jpg">portrait of Katherine Parr</a>, the sixth wife of Henry VIII, Parr wears a headdress and a multi-layered gown with billowing sleeves. </p>
<p>Several petticoats would have been required to sustain the bell shape of her skirts. If you look closely, you’ll see a thin, translucent layer of fabric that shields her exposed skin where the neckline ends. Meanwhile, a large fur mantle – at the time, an essential accessory – is draped over her arms. </p>
<h2>A removed opulence</h2>
<p>New York City’s Metropolitan Museum of Art has a <a href="http://www.metmuseum.org/about-the-met/curatorial-departments/the-costume-institute">surviving collection of clothes from the late 16th century</a>, some of which could point to the cold’s influence on Renaissance clothing.</p>
<p>For example, <a href="http://www.metmuseum.org/art/collection/search/98291?sortBy=Relevance&amp;deptids=8&amp;when=A.D.+1400-1600&amp;ft=*&amp;offset=0&amp;rpp=20&amp;pos=15">one Spanish dress</a> is outfitted with a cape atop the thick fabrics that make up the bodice, skirt and stacked sleeves. Beneath this densely layered gown, the wearer would have also needed to don several tiers of skirts and undergarments. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/185171/original/file-20170907-9563-6fe09j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/185171/original/file-20170907-9563-6fe09j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/185171/original/file-20170907-9563-6fe09j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185171/original/file-20170907-9563-6fe09j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185171/original/file-20170907-9563-6fe09j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185171/original/file-20170907-9563-6fe09j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185171/original/file-20170907-9563-6fe09j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185171/original/file-20170907-9563-6fe09j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A late 16th-century Spanish ensemble features thick fabrics.</span>
<span class="attribution"><a class="source" href="http://images.metmuseum.org/CRDImages/ci/original/DP204340.jpg">MoMA</a></span>
</figcaption>
</figure>
<p>A <a href="http://www.metmuseum.org/art/collection/search/81132">British lady’s jacket</a> from around 1616 also may hint at cold weather. Tailored from linen, silk and metal, this tight bodice probably kept its wearer very warm. (Early modern clothing often featured cloth-of-gold thread, which was made from actual thin strips of gold metal and painstakingly wrapped around sewing thread.) </p>
<p>Portraits and preserved garments from the Little Ice Age tend to have one thing in common: They are all the pictures or products of elites who enjoyed the means to have a likeness made of themselves. Their wealth is evident in the very existence of these images and the expensive clothes they wear. </p>
<p><a href="http://www.metmuseum.org/art/collection/search/81551?sortBy=Relevance&amp;deptids=8&amp;when=A.D.+1400-1600&amp;ft=hat&amp;offset=0&amp;rpp=50&amp;pos=1">Knit wool caps</a> are perfectly suitable for fending off freezing temperatures, but the wealthy women of the era instead opted for elaborate, <a href="http://www.npg.org.uk/collections/search/portrait/mw02075/Queen-Elizabeth-I">pearl-lined headdresses that trailed yards of gauzy veils</a>. </p>
<p>Their opulence ignores the various crises of the era. While countless peasants were displaced from their homes and died from starvation or rampant disease, the rich simply transitioned to sable-lined sleeves and mantels threaded with gold. </p>
<p>It’s dangerous to oversimplify historical narrative. But the parallels to our current situation are hard to ignore. Climate change is a looming threat, with deep social and political ramifications. </p>
<p>Yet for many, it remains a distant phenomenon, something that – beyond buying lighter, looser clothing – is easy to dismiss.</p><img src="https://counter.theconversation.com/content/82104/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lane Eagles does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>While today we sweat, early modern Europeans froze. Furs to the rescue.Lane Eagles, Ph.D. Candidate in Art History, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/629652016-07-26T06:37:24Z2016-07-26T06:37:24ZLand carbon storage swelled in the Little Ice Age, which bodes ill for the future<figure><img src="https://images.theconversation.com/files/131901/original/image-20160726-31171-mqzyks.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Forests and other land-based carbon stores held onto more carbon during colder historical climates.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File%3AAppalachian_Cove_forest_on_Baxter_Creek_Trail_in_Great_Smoky_Mountains_National_Park.jpg">Miguel.v/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>The dip in atmospheric carbon dioxide levels during the Little Ice Age wasn’t caused by New World pioneers cutting a swathe through native American agriculture, as had been previously thought.</p>
<p>Instead, our <a href="http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2769.html">new analysis</a> of the climate record contained within Antarctic ice cores suggests that the fall in atmospheric CO₂ levels during the cold period from 1500 to 1750 was driven by increased net uptake of carbon by plants.</p>
<p>This in turn suggests that if plants reacted to falling temperatures by taking up more carbon, they are likely to react to the current rising CO₂ levels by releasing yet more of it into the atmosphere.</p>
<h2>Historical atmospheres</h2>
<p>Atmospheric CO₂ concentrations were fairly stable from around 2000 years ago until the start of the Industrial Revolution, since when they have begun to <a href="http://onlinelibrary.wiley.com/doi/10.1029/2006GL026152/abstract">climb dramatically</a>. However, along the way were relatively small shifts, such as that seen during the Little Ice Age (LIA).</p>
<p>Carbon dioxide naturally cycles between the atmosphere, the land and the ocean. On land, it is removed from the atmosphere by plant photosynthesis and returned when plant material decomposes. Normally these processes balance out, but a change in the rate of one of these processes can shift atmospheric CO₂ levels to a new equilibrium.</p>
<p>If decomposition increases as it warms, this will slow or reverse the rebalancing uptake, leaving more carbon dioxide in the atmosphere, warming the climate still further and so on, in a positive feedback. </p>
<p>The LIA corresponded with the start of European colonisation of the New World. European diseases devastated populations in the Americas, and <a href="http://www.nature.com/nature/journal/v519/n7542/full/nature14258.html">one theory</a> held that this led to a decrease in indigenous agriculture, which in turn let forests grow back and took up significant amounts of CO₂ from the atmosphere. This had been suggested as the first geologically recognisable signature of human impact on the globe, and thus the start of the Anthropocene epoch. </p>
<p>But was this actually the case? Our study suggests not, because while we can be relatively certain the LIA change in CO₂ levels was due to differences in the behaviour of land plants, our results suggest that the change was a response to the changing climate, and not to human-driven changes in vegetation cover.</p>
<h2>Looking for clues</h2>
<p>How can we tell? We know that the process involved terrestrial plants, because the atmosphere during the LIA was even lower in CO₂ containing the isotope carbon-12, which is preferred by photosynthesising plants.</p>
<p>But how do we know if the changes were due to changes in vegetation cover, or to climate feedbacks. To answer that we looked at another gas, carbonyl sulfide (COS), which is also trapped in air bubbles along with the carbon dioxide. This molecule has almost the same structure as CO₂, except one of the oxygen atoms is replaced with sulfur. </p>
<p>This is close enough to trick the plants, which take it up during photosynthesis. But unlike CO₂, COS it is not released when plant material decomposes so an increase in photosynthesis leads to a decrease in atmospheric COS. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/131912/original/image-20160726-12618-choudk.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/131912/original/image-20160726-12618-choudk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/131912/original/image-20160726-12618-choudk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/131912/original/image-20160726-12618-choudk.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/131912/original/image-20160726-12618-choudk.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/131912/original/image-20160726-12618-choudk.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/131912/original/image-20160726-12618-choudk.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/131912/original/image-20160726-12618-choudk.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Antarctica can tell us a surprising amount about the past behaviour of forests.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>This means that the “early Anthropocene” hypothesis has a testable consequence: it should have led to an observable reduction in COS concentrations within the ice cores. However, when we looked at the ice core record we found that there was an increase. This suggests that photosynthesis actually decreased during the LIA, rather than increasing as we would expect if the difference was due to forest regrowth. </p>
<p>This means that the drop in atmospheric CO₂ during the LIA was more likely to have been a direct response to the dipping temperatures. The cool climate of the LIA reduced photosynthesis but also slowed down plant respiration and decomposition, with the net effect that more CO₂ was taken up by the land biosphere during cool periods.</p>
<h2>What about the future?</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/131913/original/image-20160726-31198-8cscnc.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/131913/original/image-20160726-31198-8cscnc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/131913/original/image-20160726-31198-8cscnc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=708&fit=crop&dpr=1 600w, https://images.theconversation.com/files/131913/original/image-20160726-31198-8cscnc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=708&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/131913/original/image-20160726-31198-8cscnc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=708&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/131913/original/image-20160726-31198-8cscnc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=890&fit=crop&dpr=1 754w, https://images.theconversation.com/files/131913/original/image-20160726-31198-8cscnc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=890&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/131913/original/image-20160726-31198-8cscnc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=890&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Frozen in time: icy bubbles capture ancient environments.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The flipside of this is that the reverse may happen when temperatures rise, as they are now. Rising temperatures are likely to mean even more CO₂ being released from the terrestrial biosphere. While plants continue to increase their photosynthesis as Earth warms, our findings suggest that plant decomposition will increase even more, meaning that less carbon stays in the soil.</p>
<p>This is concerning, because as we know, humans have opened the tap on a new source of carbon: fossil fuels that were previously locked away underground. We are rapidly returning lots of this stored carbon to the atmosphere, and the land and ocean are only removing about half of what we add.</p>
<p>Our discovery suggests that every degree increase in temperature will result in about 20 parts per million extra carbon dioxide in the atmosphere. This is about the middle of the expectation from climate models. It means that, if we want to keep global warming to within 2°C of average pre-industrial temperatures, in line with the <a href="https://theconversation.com/the-paris-climate-agreement-at-a-glance-50465">Paris climate agreement</a>, we need to factor in this positive feedback loop, which means that the more temperatures climb, the more extra CO₂ will be released from the world’s landscapes.</p><img src="https://counter.theconversation.com/content/62965/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Rayner receives funding from Australian Research Council linkage grant. </span></em></p><p class="fine-print"><em><span>Cathy Trudinger has received funding from the Australian Climate Change Science Program (a partnership between the Department of the Environment, the Bureau of Meteorology and CSIRO). </span></em></p><p class="fine-print"><em><span>David Etheridge has received funding from the Australian Climate Change Science Program (a partnership between the Department of the Environment, the Bureau of Meteorology and CSIRO), from the University of Copenhagen, from the CO2CRC and from the Gas Industry Social and Environmental Research Alliance. </span></em></p><p class="fine-print"><em><span>Mauro Rubino does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>When temperatures dipped between 1500 and 1750, the world’s landscapes responded by storing more carbon. Now, with temperatures climbing, it’s possible they will do the opposite and release even more.Peter Rayner, Professorial Fellow, The University of MelbourneCathy Trudinger, Senior Research Scientist, CSIRODavid Etheridge, Principal Research Scientist, CSIROMauro Rubino, Second University of NaplesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/446772015-07-14T16:10:02Z2015-07-14T16:10:02ZNo, we aren’t heading into a ‘mini ice age’<figure><img src="https://images.theconversation.com/files/88353/original/image-20150714-21738-dcq5ju.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">London's 'frost fairs' are a thing of the past – not the future.</span> <span class="attribution"><a class="source" href="http://www.bbc.co.uk/news/magazine-25862141">Museum of London</a></span></figcaption></figure><p>Wouldn’t it be great if scientists could make their minds up? One minute they’re telling us our planet is warming up due to human activity and we run the risk of potentially devastating environmental change. Next, they’re <a href="http://www.telegraph.co.uk/news/science/11733369/Earth-heading-for-mini-ice-age-within-15-years.html">warning that the Earth is heading for a mini ice age</a> in the next 15 years.</p>
<p>The latter headline has its roots in a recent <a href="http://nam2015.org/index.php/press-releases/64-irregular-heartbeat-of-the-sun-driven-by-double-dynamo">press release</a> from the UK’s <a href="http://nam2015.org">National Astronomy Meeting</a> that reported on a study suggesting the sun is heading towards a period of very low output. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=698&fit=crop&dpr=1 600w, https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=698&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=698&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=877&fit=crop&dpr=1 754w, https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=877&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/88346/original/image-20150714-21707-197s4lw.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=877&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Daily Telegraph was first to run the story.</span>
<span class="attribution"><a class="source" href="http://www.telegraph.co.uk/news/science/11733369/Earth-heading-for-mini-ice-age-within-15-years.html">Telegraph</a></span>
</figcaption>
</figure>
<p>Fluctuations in solar activity are not a new discovery. The <a href="http://www.livescience.com/33345-solar-cycle-sun-activity.html">11-year variation</a> in the number of dark sunspots on the solar surface was discovered more than 150 years ago. We now understand that these spots are symptoms of increased magnetic activity and occur during periods when explosive outbursts of energy and material such as <a href="http://www.nasa.gov/content/goddard/the-difference-between-flares-and-cmes">solar flares and coronal mass ejections</a> are more frequent.</p>
<p>The scientists behind the new research have modelled the rhythmic variations in solar activity over recent decades and predict that a deep low is due between 2030 and 2040. Specifically, the press release suggests that this dip in activity could mark a return to quiet solar conditions not seen for more than 350 years.</p>
<p>How is this astronomy story related to an impending ice age? The period of low solar activity in the 17th century, known as the <a href="https://en.wikipedia.org/wiki/Maunder_Minimum">Maunder minimum</a>, lasted about 70 years and roughly coincided with the “Little Ice Age”, a era characterised by an abnormally high number of harsh winters across the UK and Europe. As almost all <a href="http://www.independent.co.uk/environment/climate-change/mini-ice-age-coming-in-next-fifteen-years-new-model-of-the-suns-cycle-shows-10382400.html">newspaper stories</a> have reported, during several particularly cold winters the Thames froze, enabling <a href="http://www.bbc.co.uk/news/magazine-25862141">frost fairs</a> to be held on the ice.</p>
<p>Given the apparently strong link between low solar activity and the Little Ice Age reported in the press, it’s understandable that the prospect of a return to Maunder minimum conditions has stimulated a lot of interest. </p>
<h2>Should we be worried?</h2>
<p>If this link between variations in solar activity and changes in the Earth’s climate seems obvious, that’s because it is. When the amount of energy emitted by the sun changes, it has an affect on our climate. </p>
<p>But the real issue is just how strong this influence is compared to other factors. The total <a href="http://science.jrank.org/pages/6875/Total-Solar-Irradiance.html">solar irradiance</a>, a measure of the power produced by the sun in the form of electromagnetic radiation, varies by only about 0.1% over the course of the 11-year solar cycle. Climate scientists have understood this effect for some time and it is <a href="http://www.washingtonpost.com/news/energy-environment/wp/2015/02/23/no-the-sun-isnt-driving-global-warming/">already</a> built into the computer models that are used to try and forecast our climate.</p>
<p>But there are still some uncertainties. Changes in the ultraviolet portion of the Sun’s output over a solar cycle can be much greater and can deposit energy in the stratosphere – at altitudes above 10km. How this energy influences our weather and climate in the lower atmosphere is still not clear, but there is growing <a href="http://link.springer.com/article/10.1007%2Fs10712-012-9181-3">evidence</a> that during periods of low solar activity, atmospheric “blocking” events are more prevalent. These blocking episodes comprise extensive and almost stationary anti-cyclones in the eastern Atlantic that can last for several weeks, hindering the flow of the jet stream and leading to colder winters in the UK and Europe.</p>
<p>The good news is that if the sun is heading towards Maunder minimum conditions, the likelihood of which varies greatly in different studies, then a new ice age is not inevitable. During the Little Ice Age, the atmospheric blocking effect probably played a role, but so did <a href="http://www.sciencedaily.com/releases/2012/01/120130131509.htm">increased global volcanic activity</a> that ejected gas and ash in the atmosphere, reflecting solar radiation back into space. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=255&fit=crop&dpr=1 600w, https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=255&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=255&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=320&fit=crop&dpr=1 754w, https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=320&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/88357/original/image-20150714-21738-1bbmolu.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=320&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Little Ice Age began before the Maunder minimum.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Sunspot_Numbers.png">Hoyt & Schatten / wiki</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>So we have to be careful associating the Maunder minimum with the Little Ice Age. A look at the data shows that the Little Ice Age began a long time (certainly more than a century) before the start of the Maunder minimum – and continued long after it ended. In any case, the Little Ice Age wasn’t really an ice age. Although cold winters in Europe were unusually common, it doesn’t seem to have been a global phenomenon. <a href="http://download.springer.com/static/pdf/590/art%3A10.1007%2Fs10712-012-9181-3.pdf?originUrl=http%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs10712-012-9181-3&token2=exp=1436832094%7Eacl=%2Fstatic%2Fpdf%2F590%2Fart%3A10.1007%2Fs10712-012-9181-3.pdf%3ForiginUrl%3Dhttp%3A%2F%2Flink.springer.com%2Farticle%2F10.1007%2Fs10712-012-9181-3*%7Ehmac=a114ec160a0d978e4807c4934ffd2942ab3f184103b2bda8e814968366bcea7e">Research</a> suggests it was a regional phenomenon and that the colder winters in Europe would have been accompanied by warmer ones elsewhere.</p>
<p>So what about global climate change? If solar activity is falling, and that has a cooling influence over the UK and Europe, isn’t that a good thing?</p>
<p>Unfortunately not. The overwhelming consensus among the world’s climate scientists is that the influence of solar variability on the climate is dwarfed by the impact of increased levels of carbon dioxide in the atmosphere. Most <a href="http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/aug/14/global-warming-solar-minimum-barely-dent">calculations</a> suggest that a new “grand solar minimum” in activity would have a cooling effect that would temporarily offset just a few year’s worth of the warming due to the emission of carbon dioxide by humans.</p>
<p>We may well be heading towards a period of low solar activity, but a new mini ice age seems very unlikely at this point.</p><img src="https://counter.theconversation.com/content/44677/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jim Wild receives funding from the Science and Technology Facilities Council and the Natural Environment Research Council. He is also the vice-President (Geophysics) of the Royal Astronomical Society, but is writing here as an independent academic scientist. He occasionally works with a variety of UK-based travel and tourism companies to engage relevant audiences on topics related to his research.
</span></em></p>Any drop in solar activity will be dwarfed by the impact of increased carbon dioxide in the atmosphere.Jim Wild, Professor of Space Physics, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/277422014-07-24T04:24:08Z2014-07-24T04:24:08ZThe ‘pre-Holocene’ climate is returning – and it won’t be fun<figure><img src="https://images.theconversation.com/files/53168/original/zncj6xzg-1404718180.jpg?ixlib=rb-1.1.0&rect=0%2C1%2C794%2C442&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The polar vortex played havoc with Niagara Falls (and much of the rest of North America too).</span> <span class="attribution"><span class="source">EPA/Rick Warne</span></span></figcaption></figure><p>A string of events earlier this year provided a sobering snapshot of a global climate system out of whack. Europe suffered <a href="http://www.rtcc.org/2014/01/08/europes-floods-trump-haiyan-as-the-costliest-natural-disaster-of-2013/">devastating floods</a>, Britain’s coastline was <a href="http://www.theguardian.com/uk-news/2014/jan/07/uk-floods-chesil-beach-sirens">mauled</a>, and the <a href="http://www.huffingtonpost.com/2014/01/03/cold-us-temperatures_n_4538827.html">polar vortex</a> cast a <a href="http://www.cnbc.com/id/101319397">US$5 billion economic chill</a> over America. Meanwhile, an abnormally mild winter in Scandinavia <a href="http://www.theguardian.com/environment/2014/jan/10/polar-vortex-us-mild-weather-scandinavia">disrupted bears’ hibernation</a>; while Australia was ravaged by <a href="https://theconversation.com/australias-climate-time-to-act-on-rising-heatwaves-and-fires-23927">fires</a> and <a href="http://www.bom.gov.au/climate/current/statements/scs48.pdf">record-breaking heat</a>.</p>
<p>These happenings give us an idea of what life must have been like in the lead-up to the <a href="http://www.ucmp.berkeley.edu/quaternary/holocene.php">Holocene Epoch</a>, living on the brink of seismic change, amid a series of abrupt climate shifts.</p>
<p>As the archaeologist Steven Mithen wrote in his book <a href="http://www.amazon.com/After-Ice-Global-History-000-5000/dp/0674019997">After the Ice</a>:</p>
<blockquote>
<p>People were thin on the ground and struggling with a deteriorating climate … massive ice sheets had expanded across much of North America, Northern Europe and Asia. The planet was inundated by drought, sea level had fallen to expose vast and often barren coastal plains. Human communities survived the harshest conditions by retreating to refugia where firewood and foodstuffs could still be found.</p>
</blockquote>
<p>Since then, we have been lulled into a false sense of security by the ensuing 10,000-odd years of peaceful, stable climate during the Holocene itself. This has allowed us to tame crops and livestock, and to come together to form communities, villages and, ultimately, cities. </p>
<p>But the calm and tranquil Holocene has now been replaced by the <a href="https://theconversation.com/human-global-domination-began-with-fire-not-factories-or-farms-20317">Anthropocene</a> – heralding a return to a volatile and destructive climate. Truly, we have woken an <a href="https://theconversation.com/forget-saving-the-earth-its-an-angry-beast-that-weve-awoken-27156">angry beast</a> from its slumber.</p>
<h2>From ice age to rapid warming</h2>
<p>When the last ice age <a href="http://www.sciencedaily.com/releases/2008/06/080619142112.htm">began to teeter 14,700 years ago</a>, meltwater began to pour into the oceans, raising levels by up to half a metre per decade. The sea moved inland like a slow tsunami. </p>
<p>But after a hesitant couple of millennia of warmer conditions, the cold was back with a vengeance, turning western Asia and Europe into ice empires. This event, dubbed the <a href="http://www.ncdc.noaa.gov/paleo/abrupt/data4.html">Younger Dryas</a>, derived from the collapse of the ice walls on Lake Agassiz in North America, sending freshwater flooding into the Atlantic and Arctic Oceans. As a result it cut back the Gulf Stream, returning the planet to cool and dry conditions in a matter of decades, with the average Northern Hemisphere temperature plummeting by 7C.</p>
<p>These cold conditions lasted for about 1400 years. Then, just as rapidly, the warm and wet conditions returned, marking the beginning of the Holocene about 11,700 years ago.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/54536/original/hkddz763-1406011358.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/54536/original/hkddz763-1406011358.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/54536/original/hkddz763-1406011358.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=472&fit=crop&dpr=1 600w, https://images.theconversation.com/files/54536/original/hkddz763-1406011358.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=472&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/54536/original/hkddz763-1406011358.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=472&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/54536/original/hkddz763-1406011358.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=594&fit=crop&dpr=1 754w, https://images.theconversation.com/files/54536/original/hkddz763-1406011358.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=594&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/54536/original/hkddz763-1406011358.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=594&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Extent of the glacial Lake Agassiz roughly 7900 years ago. Several millennia earlier it dumped freshwater into the oceans, causing widespread cooling.</span>
<span class="attribution"><a class="source" href="http://commons.wikimedia.org/wiki/File%3A7%2C900_Glacial_Lake_Agassiz_%26_Glacial_Lake_Ojibway_(7900)_use_fileTeller_and_Leverington%2C_2004.jpg">Chris Light/Wikimedia Commons (derived from USGS data)</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Stable era</h2>
<p>Since then, the world’s climate has remained remarkably stable – boring, even. The relatively static shorelines have made farming, fishing, towns and cities possible. </p>
<p>Humans have got used to thinking that this is a natural state of affairs. But, as James Hansen <a href="http://www.columbia.edu/%7Ejeh1">has declared</a>, “it’s our relatively static experience of climate that is actually exceptional”. </p>
<p>Of course, there have been divergences from the norm, although these have thankfully been few and far between. One was 5000 years ago, when the Sahara went from a land of hippos and giraffes to desert in <a href="http://www.livescience.com/28493-when-sahara-desert-formed.html">a mere 100-200 years</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/54534/original/z3yqpvvg-1406011156.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/54534/original/z3yqpvvg-1406011156.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/54534/original/z3yqpvvg-1406011156.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/54534/original/z3yqpvvg-1406011156.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/54534/original/z3yqpvvg-1406011156.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/54534/original/z3yqpvvg-1406011156.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/54534/original/z3yqpvvg-1406011156.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/54534/original/z3yqpvvg-1406011156.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In geological terms, the Sahara became a desert overnight.</span>
<span class="attribution"><a class="source" href="http://commons.wikimedia.org/wiki/File%3AErg_Chegaga.JPG">GaetanP123/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>That event was caused by gradual changes to the Earth’s orientation towards the Sun. It shows us that even when the forces are gradual, the climate may not always respond gradually but instead can move in juddering, unpredictable shifts.</p>
<p>At about the same time, seismic change was happening in our own midst, with the eruption of Mount Gambier <a href="http://www.abc.net.au/news/2013-12-11/experts-estimate-size-of-mount-gambier-volcano/5149948">sending an ash plume up to 10 km high</a> – an event that would have partially obscured the Sun. </p>
<p>Eruptions like this were the main cause of climate variability in the Holocene, causing cooler, drier episodes such as the “<a href="http://www.rtcc.org/2013/12/23/scientists-dismiss-solar-link-to-medieval-little-ice-age">Mediaeval little ice age</a>”.</p>
<h2>Things are different now</h2>
<p>Now, however, carbon dioxide has reached levels not seen for <a href="http://www.nature.com/nature/journal/v406/n6797/abs/406695a0.html">at least 3 million years</a>, and fossil fuel emissions have become the dominant driver of the changes to our climate. In a world potentially several degrees warmer than the one that spawned our civilization, we had better ready ourselves for <a href="http://www.nap.edu/catalog.php?record_id=18373">some surprises</a>.</p>
<p>This isn’t alarmism; it’s just sensible risk management. Retired US Navy Rear Admiral David Titley, now head of Penn State’s <a href="http://solutions2wxrisk.psu.edu">Center for Solutions to Weather and Climate Risk</a>, pointed out that governments still spend money on defence, despite the declining number of people killed worldwide in war. He <a href="http://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/dec/26/republicans-congress-climate-change-testimony-risk">told the US Congress</a> that “we rightly invest in our security and defence as one component of hedging against unknown or unlikely security risks”. Inaction on climate change violates that same fundamental risk-management principle.</p>
<h2>What’s nature ever done for us?</h2>
<p>Of course, nature will carry on regardless, albeit savaged. As the MIT physicist and humanities professor Alan Lightman has <a href="http://www.nytimes.com/2014/05/03/opinion/our-lonely-home-in-nature.html?ref=opinion&_r=0">noted</a>, “tornadoes, hurricanes, floods, earthquakes and volcanic eruptions happen without the slightest consideration for human inhabitants”. </p>
<p>Yet if we turn our backs on nature, while at the same time climbing the population hill to nine billion, we will create a <a href="http://www.sustainable.unimelb.edu.au/files/mssi/MSSI-IssuesPaper-3_Gleeson_2014_0.pdf">horrid future for humanity’s survivors</a>, with <a href="http://bit.ly/1lPqmMB">ongoing wild species extinctions</a> and a world polluted by <a href="http://www.epa.gov/ppcp">human-invented chemicals</a>. </p>
<p>Some have predicted that, within just two or three centuries, <a href="http://scienceblogs.com/grrlscientist/2006/11/11/eremozoic-era">we could be alone except for pets, chickens, livestock, and an unknown suite of microbes and freeloaders such as mice and cockroaches</a>. </p>
<p>For a sneak preview of this “biosimplification”, look no further than the swathes of European countryside where there has been a crash in bird populations – no songs, no glimpses of plumage, just an eerie silence – as a result of the wholesale ripping up of hedgerows, draining of wetlands and ploughing over of meadows robbing farmland birds of their homes and sustenance in order to <a href="http://www.theguardian.com/environment/2012/may/26/eu-farming-policies-bird-population">boost farming production</a>. </p>
<p>That would leave us living in a drab, crummy landscape where surviving native plants cower in small niches away from the weeds; zoos exhibit a lost fauna; and <a href="http://www.britannica.com/EBchecked/topic/1714435/biophilia-hypothesis">biophilia</a> is reduced to watching carp. </p>
<p>It’s surely a trajectory that’s worth getting off.</p><img src="https://counter.theconversation.com/content/27742/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Fisher does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A string of events earlier this year provided a sobering snapshot of a global climate system out of whack. Europe suffered devastating floods, Britain’s coastline was mauled, and the polar vortex cast…Peter Fisher, Adjunct Professor, Global, Urban and Social Studies, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.