tag:theconversation.com,2011:/id/topics/certainty-7312/articlesCertainty – The Conversation2021-09-15T03:28:38Ztag:theconversation.com,2011:article/1669032021-09-15T03:28:38Z2021-09-15T03:28:38ZThe shifting sands of COVID and our uncertain future has a name – liminality<figure><img src="https://images.theconversation.com/files/421236/original/file-20210915-23-7v8a9l.jpg?ixlib=rb-1.1.0&rect=0%2C1%2C1000%2C416&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/multiple-closed-doors-desert-one-open-1685188615">Shutterstock</a></span></figcaption></figure><p>During the pandemic, lots of us, myself included, are struggling to live in the “now”. That “now”, with all its uncertainty, doesn’t look like the life we used to live or the life we imagine we will return to.</p>
<p>That experience has a name — liminality. </p>
<p>Understanding liminality and its origins can provide ways to better understand the foggy, ambiguous space we currently inhabit.</p>
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Read more:
<a href="https://theconversation.com/not-all-doom-and-gloom-even-in-a-pandemic-mixed-emotions-are-more-common-than-negative-ones-138014">Not all doom and gloom: even in a pandemic, mixed emotions are more common than negative ones</a>
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<h2>What is liminality?</h2>
<p>European anthropologist Arnold van Gennep <a href="https://www.researchgate.net/publication/283237814_The_Base_Articulations_of_the_Liminality_Concept">pioneered</a> the study of liminality in the early 20th century. His work on liminal spaces focused on the rites of passage we transition through in life. </p>
<p>Since then, the term liminality has been used to describe the paths we navigate when faced with life events. These are the times when we are in a metaphorical waiting room between one life stage and another.</p>
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<p>I’ve <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/inm.12909">been studying</a> liminality throughout my career working with families of missing people.</p>
<p>These families, waiting for missing people to come home, can also experience a sense of liminality. They can be stuck between certainty and uncertainty about knowing what happened to their loved ones and learning to live without answers.</p>
<p>What families of missing people taught me is what helps us survive uncertainty is reflecting on our own capacity to tolerate “<a href="https://www.researchgate.net/publication/340285925_'An_all-consuming_cumulonimbus_of_pain'_a_scoping_review_exploring_the_impact_of_ambiguous_loss_when_someone_is_missing_and_the_counselling_interventions_relevant_to_the_experience">not knowing</a>”.</p>
<p>An everyday example might be sitting an exam and waiting for the outcome. You might be unable to plan ahead, and are balancing thoughts of passing or failing, all at the same time.</p>
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Read more:
<a href="https://theconversation.com/languishing-burnout-and-stigma-are-all-among-the-possible-psychological-impacts-as-delta-lingers-in-the-community-167103">Languishing, burnout and stigma are all among the possible psychological impacts as Delta lingers in the community</a>
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<h2>What’s this to do with COVID?</h2>
<p>During COVID, how we believe our lives “should” work ceases to exist. And we’re left with uncertainty.</p>
<p>We ask ourselves, others or Google “how long will the pandemic last?”, “when will lockdown end” or “when can we safely travel?”.</p>
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<p>Liminality shows up in other ways, with the:</p>
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<li><p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7375263/">lost life-stage rituals</a> such as the sudden end of the school year, but without the formals or graduation ceremonies</p></li>
<li><p>newfound uncertainty about daily tasks we once took for granted. “I just need to pop to the shops” is now an exercise in decisions and questions about masks, social distancing and what’s essential</p></li>
<li><p>grandparents who haven’t cuddled their first grandchild and made that transition to a new stage of their life. They may live between saying “well at least we are healthy” while quietly lamenting those missed opportunities.</p></li>
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Read more:
<a href="https://theconversation.com/learning-to-cope-with-uncertainty-during-covid-19-151420">Learning to cope with uncertainty during COVID-19</a>
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<h2>There are real health impacts</h2>
<p>The space between the life we had and the life we potentially will be able to live <a href="https://theconversation.com/learning-to-cope-with-uncertainty-during-covid-19-151420">can cause us distress</a>. And no amount of Zoom trivia, Uber Eats delivery or walking around the block can satisfy us.</p>
<p>Liminality during COVID has also impacting our health and well-being in other ways.</p>
<p>People with <a href="https://link.springer.com/content/pdf/10.1186/s40337-020-00306-3.pdf">eating disorders</a> have noted an increase in behaviours, as a coping tool, when faced with uncertainty. Diabetes educators have noted increased isolation and disconnection from usual routines <a href="https://www.sciencedirect.com/science/article/pii/S0168822720305957?casa_token=-5srxXDJ85QAAAAA:rsG_56ZGXhMxvQyvZOQoep28CO_x-WdE3_N4LA-kM-5X2MtGs6Wox9b_lqhb1uEH0C37fjga0Q">can impact</a> how diabetes is managed.</p>
<p>But the liminal space can also provide <a href="https://www.researchgate.net/profile/Mohamed-Buheji/publication/343655515_Living_Uncertainty_in_the_New_Normal/links/5f3696a9299bf13404c1d8d9/Living-Uncertainty-in-the-New-Normal.pdf">breathing room</a> to learn to live with uncertainty and overcome what scares us.</p>
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Read more:
<a href="https://theconversation.com/its-ok-if-you-have-a-little-cry-in-lockdown-youre-grieving-165329">It's OK if you have a little cry in lockdown. You're grieving</a>
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<h2>How to cope with uncertainty</h2>
<p>To manage uncertainty, individually and collectively, we need to reflect on how we receive information. </p>
<p><a href="https://academic.oup.com/her/article/36/2/178/6120242?login=true">A US study</a> found one place we go to for information, for certainty in a pandemic, is science. However, given science changes as research progresses, public health messaging can also change. So this repetitive looking for certainty, in an uncertain world, makes it difficult to learn to live with COVID. </p>
<p>We know long periods of uncertainty <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6221042/#hec3795-bib-0026">can have impacts</a> on our capacity to cope. Without the strong foundation of certainty or “knowns” in our life, the reshaping of the world, from the pandemic, can and will be unsettling.</p>
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Read more:
<a href="https://theconversation.com/life-is-full-of-uncertainty-weve-just-got-to-learn-to-live-with-it-30092">Life is full of uncertainty, we've just got to learn to live with it</a>
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<a href="https://images.theconversation.com/files/421237/original/file-20210915-21-1hd7wt4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Young woman wearing mask scrolling smartphone sitting outside" src="https://images.theconversation.com/files/421237/original/file-20210915-21-1hd7wt4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/421237/original/file-20210915-21-1hd7wt4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/421237/original/file-20210915-21-1hd7wt4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/421237/original/file-20210915-21-1hd7wt4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/421237/original/file-20210915-21-1hd7wt4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/421237/original/file-20210915-21-1hd7wt4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/421237/original/file-20210915-21-1hd7wt4.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"></a>
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<span class="caption">Do we really need to stay up-to-date with the latest twists and turns of the news cycle?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/asian-young-woman-medical-mask-sitting-2037070865">Shutterstock</a></span>
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<p>I’m not suggesting abandoning science, far from it. But those not at the forefront of designing vaccines, studying epidemiological trends or treating COVID patients might like to rethink our relationship with certainty. </p>
<p>Learning to “go with” all the twists and turns that come with rapidly changing science and the resultant uncertainty is what we need. We might enhance our lives by accepting liminality in how we navigate each day, to learn to tolerate ambiguity.</p>
<p>It is not simple to accept the unknown. However in this pandemic, learning to accept public health advice (and the science that underpins it) might change is part of living through a worldwide event. </p>
<p>Not knowing what next week will look like and finding ways to “tolerate ambiguity” is where we’re at right now. We can help ourselves by finding daily routines within our control, small moments of the day where we connect with a person, nature, or an activity that reminds us where we are and who we are.</p>
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Read more:
<a href="https://theconversation.com/coronavirus-tiny-moments-of-pleasure-really-can-help-us-through-this-stressful-time-134043">Coronavirus: tiny moments of pleasure really can help us through this stressful time</a>
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<p>We also need space to safely grieve the small and big losses COVID has created. We need to accept that, globally, we are in the liminal space between here and there. </p>
<p>Hopefully, “there” is when life returns to somewhat normal and when popping down to the shops means just that.</p><img src="https://counter.theconversation.com/content/166903/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sarah Wayland 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>Understanding liminality and its origins can provide ways to better understand the foggy, ambiguous space we’re experiencing right now.Sarah Wayland, Senior Lecturer Social Work, University of New EnglandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/171812013-08-23T01:55:31Z2013-08-23T01:55:31ZLost in translation: confidence and certainty in climate science<figure><img src="https://images.theconversation.com/files/29660/original/m4vz4cct-1377063827.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Certainty about humanity's influence on climate change has been steadily increasing.</span> <span class="attribution"><span class="source">carnagenyc/Flickr</span></span></figcaption></figure><p><em>In the lead up to the release next month of the Intergovernmental Panel on Climate Change’s (IPCC’s) <a href="http://www.ipcc.ch/scripts/_calendar_template.php?wg=8">Fifth Assessment Report</a> we are exploring concepts of confidence and certainty in climate science. You can find the other articles <a href="https://theconversation.com/topics/climate-science">here</a></em></p>
<p>“Virtually certain”, “extremely likely”, and “high confidence”: these terms get bandied about in climate science, but what do they really mean? And what do they mean for us? </p>
<p>The previous IPCC report <a href="http://www.ipcc.ch/publications_and_data/ar4/syr/en/contents.html">(AR4)</a> from 2007 expressed “very high confidence” that global average temperature increases were very likely due to the observed increases in greenhouse gases concentrations. </p>
<p>Various leaked draft reports suggest that in the imminent fifth assessment, our understanding of the human causes of global warming has strengthened. The leaks suggest the upcoming report could raise that level to “extremely likely” or even <a href="https://theconversation.com/human-role-in-climate-change-now-virtually-certain-leaked-ipcc-report-11357">“virtually certain”</a>. </p>
<p>In this series we have discussed <a href="https://theconversation.com/150-years-and-counting-confidence-in-climate-science-17179">confidence</a> and <a href="https://theconversation.com/in-science-the-only-certainty-is-uncertainty-17180">likelihood</a>. These are used to communicate the degree of scientific certainty in key findings. </p>
<p>In the IPCC reports, confidence is expressed qualitatively and tells us how certain we are that scientific findings are valid. The level of confidence is determined by the type, amount, quality and consistency of evidence. A “very high confidence” means that there is at least a 9 in 10 chance of a finding being correct.</p>
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<img alt="" src="https://images.theconversation.com/files/29650/original/yp5zpvsf-1377055970.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/29650/original/yp5zpvsf-1377055970.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=168&fit=crop&dpr=1 600w, https://images.theconversation.com/files/29650/original/yp5zpvsf-1377055970.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=168&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/29650/original/yp5zpvsf-1377055970.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=168&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/29650/original/yp5zpvsf-1377055970.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=212&fit=crop&dpr=1 754w, https://images.theconversation.com/files/29650/original/yp5zpvsf-1377055970.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=212&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/29650/original/yp5zpvsf-1377055970.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=212&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 scales of scientific confidence used by the IPCC.</span>
<span class="attribution"><span class="source">http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch1s1-6.html</span></span>
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<p>The certainty of scientific findings is then described using likelihoods. Findings are assessed probabilistically using observations, modelling results or expert judgement. They are assigned a term from a scale ranging from exceptionally unlikely (less that 1% probable) to virtually certain (more than 99% probable). </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/29652/original/myg89y6t-1377056072.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/29652/original/myg89y6t-1377056072.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=261&fit=crop&dpr=1 600w, https://images.theconversation.com/files/29652/original/myg89y6t-1377056072.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=261&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/29652/original/myg89y6t-1377056072.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=261&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/29652/original/myg89y6t-1377056072.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=329&fit=crop&dpr=1 754w, https://images.theconversation.com/files/29652/original/myg89y6t-1377056072.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=329&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/29652/original/myg89y6t-1377056072.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=329&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">IPCC measures certainty using the likelihood scale. The highest scientific certainty we can convey is virtually certain (99-100% probability).</span>
<span class="attribution"><span class="source">http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch1s1-6.html</span></span>
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<p>The IPCC uses these scales to convey specific information about our understanding of, and confidence in, scientific findings. Results with low confidence can be framed as such, and are treated as areas that need further investigation. Conversely, scientific findings that are backed up by multiple, consistent and independent lines of high-quality evidence are communicated with high confidence. </p>
<p>It’s understandable that terms like “virtually certain”, “extremely likely” and “very high confidence” create some confusion as to how sure climate scientists are about anthropogenic climate change. </p>
<p><a href="http://ipcc-wg2.gov/SREX/">We are “virtually certain”</a>, for example, that there will be an increase in the frequency and severity of extreme high temperatures. At first “virtually certain” might sound unclear. It might sound a little confused, or perhaps that the fundamental science isn’t quite settled yet. </p>
<p>But as we have shown in our previous pieces in this series, the use of the terms “virtually certain” and “extremely likely” illustrates the vast body of consistent scientific evidence around climate change that has been established over the last 150 years. </p>
<p>Often commentators point to remaining uncertainties in our understanding of climate change as a reason to delay on action. But our certainty has been steadily increasing. In 2001, the IPCC concluded that the human influences on the climate were likely (greater than 66% probability) already detectable. This increased to very likely (greater than 90% probability) by the 2007 IPCC report. </p>
<p>This trend is clear. The upcoming report will likely deliver an even stronger statement on the human role in climate change, close to the highest level of certainty we can communicate and reflecting the high level of <a href="https://theconversation.com/its-true-97-of-research-papers-say-climate-change-is-happening-14051">scientific consensus</a>.</p>
<p>Climate change is clearly a broad, complex problem requiring consideration from scientists, politicians, communities and individuals. But the language employed by the IPCC tells us that human-caused temperature increases is a well-understood theory, comparable to our understanding of gravity. </p>
<p>With this degree of scientific confidence, it’s time to stop suggesting that any remaining scientific uncertainty is what’s holding us back from decisive action on this increasingly urgent matter. With so much at stake, do we really want to bet against these odds? </p><img src="https://counter.theconversation.com/content/17181/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sophie Lewis is a Research Fellow at the Melbourne University node of the ARC Centre of Excellence for Climate System Science.
</span></em></p><p class="fine-print"><em><span>Ailie Gallant receives funding from Monash University. She is affiliated with the Centre of Excellence for Climate System Science.
</span></em></p>In the lead up to the release next month of the Intergovernmental Panel on Climate Change’s (IPCC’s) Fifth Assessment Report we are exploring concepts of confidence and certainty in climate science. You…Sophie Lewis, Postdoctoral Research Fellow, The University of MelbourneAilie Gallant, Lecturer, School of Geography and Environmental Science, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/171802013-08-22T01:05:31Z2013-08-22T01:05:31ZIn science, the only certainty is uncertainty<figure><img src="https://images.theconversation.com/files/29632/original/xwgb2vpf-1377050825.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">We are used to thinking in probabilities: will it be stormy enough to need an umbrella?</span> <span class="attribution"><span class="source">Luis Martins</span></span></figcaption></figure><p><em>In the lead up to the release next month of the Intergovernmental Panel on Climate Change’s (IPCC’s) <a href="http://www.ipcc.ch/scripts/_calendar_template.php?wg=8">Fifth Assessment Report</a> we are exploring concepts of confidence and certainty in climate science. You can find the first article <a href="https://theconversation.com/penguins-cant-fly-and-humans-are-causing-climate-change-how-scientists-build-theories-15348">here</a>, and the second <a href="https://theconversation.com/150-years-and-counting-confidence-in-climate-science-17179">here</a></em></p>
<p>Scientists have built a theory of climate change from <a href="https://theconversation.com/150-years-and-counting-confidence-in-climate-science-17179">multiple lines</a> of consistent, high-quality evidence. Just as we are confident that <a href="https://theconversation.com/penguins-cant-fly-and-humans-are-causing-climate-change-how-scientists-build-theories-15348">penguins can’t fly</a> and that our skydiving scientist plummets under gravity, we are also confident in our understanding of human-induced climate change.</p>
<p>But simple statements implicating the human causes of climate change contain many complexities. The specifics are important too - what’s in store for the future? And how sure are we of these future climate impacts? </p>
<p>Even with our increasingly sophisticated knowledge of the climate system, there are aspects where questions remain and <a href="http://rsta.royalsocietypublishing.org/content/369/1956/4681.full">uncertainties</a> we need to consider. Scientists need to be able to express these nuances in scientific findings, which means quantifying how much we understand. </p>
<p>We can again think of the evidence of climate change as a <a href="https://theconversation.com/150-years-and-counting-confidence-in-climate-science-17179">jigsaw puzzle</a>. All information has at least a small degree of uncertainty, so we can imagine each puzzle piece is imperfect: they might be a little bit out of focus, or perhaps slightly discoloured. But despite their imperfections, they are still recognisable. </p>
<p>These are tangible uncertainties, our “<a href="http://en.wikipedia.org/wiki/There_are_known_knowns">known unknowns</a>”. The same measurements of the same phenomena will always be slightly different. There are limits on our computing capacity and representing the earth’s complex physical systems with numbers is complicated. </p>
<p>These uncertainties can be quantified and accounted for as part of the scientific process. We have a good idea of just how blurry or discoloured these pieces are and what they are showing us. </p>
<p>Then there are the bits of the puzzle we don’t even realise are missing yet. These are “unknown unknowns”. They are bits of our puzzle at the limits of our reasoning or modelling, so their uncertainties can’t be <a href="http://www.tandfonline.com/doi/abs/10.1080/09505439909526558#.UfsHI1Na9PE">quantified</a>. </p>
<p>In science, there are complexities in all questions. For example, we can ask what kind of changes we will see in temperature extremes in coming decades. Scientists are confident that temperature extremes will become more frequent, but in order to express some of the complexity encompassed in that outcome, scales of likelihood are used describe the level of certainty. </p>
<p><a href="http://ipcc-wg2.gov/SREX/">We are “virtually certain”</a> (99-100% probability) we will see an increase in the frequency and severity of extreme high temperatures. Here, the uncertainty of a particular finding has been quantified in probabilistic terms. </p>
<p>Using probabilistic thinking comes naturally to us in everyday life and we use it to weigh up risks. For example, we decide whether to take an umbrella to work based on the likelihood of rain. </p>
<p>But despite our familiarity with probabilities, the language of uncertainty can be confusing. When taken out of a scientific context, “uncertainties” seem to indicate that scientists are just plain wrong. </p>
<p>In scientific discourse, “uncertainty” does not imply that the science is unreliable. Instead, uncertainty is about probabilities and likelihoods that describe our understanding of a particular outcome. </p>
<p>Like those unexpected rainy days that keep us guessing, scientific information is never completely, unequivocally certain. <a href="http://www.senseaboutscience.org/data/files/resources/127/SAS012_MSU_ONLINE.pdf">All our attempts</a> to understand complex systems and future changes come with uncertainty. So, we do not, and should not, draw conclusions from a single piece of evidence. We discern the picture of climate change by looking at all our puzzle pieces together.</p>
<p>Ultimately, the only scientific certainty is uncertainty. At times, these inevitable scientific uncertainties have been framed as synonymous with <a href="http://www.skepticalscience.com/climate-of-doubt-strategy-2-exaggerate-uncertainty.html">doubt</a> and used to try to discredit findings. </p>
<p>But uncertainty is not a weakness of science. Rather than eroding our scientific confidence in human-caused climate change, using probabilities to talk about scientific uncertainties allows scientists to communicate findings more precisely and transparently. </p><img src="https://counter.theconversation.com/content/17180/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sophie Lewis is a Research Fellow at the Melbourne University node of the ARC Centre of Excellence for Climate System Science</span></em></p><p class="fine-print"><em><span>Ailie Gallant receives funding from Monash University. She is affiliated with the Centre of Excellence for Climate System Science.</span></em></p>In the lead up to the release next month of the Intergovernmental Panel on Climate Change’s (IPCC’s) Fifth Assessment Report we are exploring concepts of confidence and certainty in climate science. You…Sophie Lewis, Postdoctoral Research Fellow, The University of MelbourneAilie Gallant, Lecturer, School of Geography and Environmental Science, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/171792013-08-21T00:58:39Z2013-08-21T00:58:39Z150 years and counting: confidence in climate science<figure><img src="https://images.theconversation.com/files/29558/original/7f9wv293-1376964766.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sometimes a piece of the puzzle won't fit, but overall the picture is coming together.</span> <span class="attribution"><span class="source">Dave Ginsberg</span></span></figcaption></figure><p><em>In the lead up to the release next month of the Intergovernmental Panel on Climate Change’s (IPCC’s) <a href="http://www.ipcc.ch/scripts/_calendar_template.php?wg=8">Fifth Assessment Report</a> we are exploring concepts of confidence and certainty in climate science. The first article is <a href="https://theconversation.com/penguins-cant-fly-and-humans-are-causing-climate-change-how-scientists-build-theories-15348">here</a></em></p>
<p>Building <a href="https://theconversation.com/penguins-cant-fly-and-humans-are-causing-climate-change-how-scientists-build-theories-15348">any scientific theory</a> is like putting together pieces of a jigsaw puzzle. Pieces of evidence are assembled in order to resolve the complete picture. </p>
<p>And the picture has never been clearer for the puzzle of human-induced climate change. </p>
<p>The theory that additional carbon dioxide (CO<sub>2</sub>) in the atmosphere would increase global temperatures, and cause other changes to Earth’s climate, is <a href="http://www.aip.org/history/climate/timeline.htm">not new</a>. That puzzle box was opened nearly 200 years ago. </p>
<p><a href="http://www-history.mcs.st-and.ac.uk/Biographies/Fourier.html">Joseph Fourier</a>, who made the initial hypothesis of a greenhouse effect, identified the very first piece of the climate change puzzle in 1824. In 1859, <a href="http://www.answers.com/topic/john-tyndall">John Tyndall</a> identified the “greenhouse gases” and their role in the atmosphere. </p>
<p>In 1896, Svante Arrhenius made the first suggestion that humans could influence the climate. Even well over 100 years ago, he postulated that global temperatures would rise by 5-6C if the CO<sub>2</sub> concentration of the atmosphere was doubled.</p>
<p>More puzzle pieces were added when Brooks reported increases in temperatures in the 1920s. But it was Guy Callendar who, through meticulous examinations undertaken from the late <a href="http://www.aip.org/history/climate/20ctrend.htm">1930s to 1960s</a>, identified not only increases in global temperatures, but also suggested that these were caused by human emissions of greenhouse gases.</p>
<p>By the late 1950s and into the 1960s the atmosphere was being studied in increasing detail with the sudden expansion of observations that were associated with the <a href="http://en.wikipedia.org/wiki/International_Geophysical_Year">International Geophysical Year</a>. In addition, scientists gathered yet more puzzle pieces with the advent of computers that could <a href="http://celebrating200years.noaa.gov/breakthroughs/climate_model/">accurately model the physics of the atmosphere</a>. </p>
<p>In 1960, Charles Keeling first published what is now known as the “<a href="http://keelingcurve.ucsd.edu/the-history-of-the-keeling-curve/">Keeling Curve</a>”, showing consistent rises in observed atmospheric CO<sub>2</sub>. </p>
<p>By now, the scientific puzzle was well and truly taking shape. There was clear evidence that CO<sub>2</sub>. was increasing in our atmosphere and that temperatures were increasing concurrently. Many independent lines of evidence were consistent with Arrhenius’ theory from over 60 years prior.</p>
<p>Throughout the latter half of the 20th century, this evidence continued to grow, increasing confidence in the theory that humans were affecting the climate. Scientists used high accuracy instruments to observe changes, reconstructed past climatic changes and also modelled the climate system using the fundamental laws of physics and chemistry.</p>
<p>At the same time, the number of alternative hypotheses about the observed warming declined. While scientists were neatly putting together these puzzle pieces, they were also examining whether any other known process, besides human activities, could be responsible for the observed changes. Solar variations, volcanoes and other natural cycles were all systematically discounted. </p>
<p>From 1991 to 2011 alone, more than 4,000 additional pieces of the climate change puzzle were gathered. An estimated <a href="https://theconversation.com/its-true-97-of-research-papers-say-climate-change-is-happening-14051">97% of them fit the puzzle and were consistent with previous evidence</a>. So of these 4,000 pieces, 3,880 pieces demonstrated that humans were having a noticeable and significant influence on our climate.</p>
<p>Trying to construct a puzzle is difficult and time consuming. You might lose a few pieces along the way, and sometimes some pieces just don’t fit. But as with any large puzzle, there comes a point where there are enough pieces, enough consistent evidence, to be able to resolve the picture. </p>
<p>The result of nearly 200 years of scientific endeavour is now a clear and recognisable picture of humans influencing the climate through the emission of greenhouse gases. </p><img src="https://counter.theconversation.com/content/17179/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ailie Gallant receives funding from Monash University. She is affiliated with the Centre of Excellence for Climate System Science.</span></em></p><p class="fine-print"><em><span>Sophie Lewis is a Research Fellow at the Melbourne University node of the ARC Centre of Excellence for Climate System Science.</span></em></p>In the lead up to the release next month of the Intergovernmental Panel on Climate Change’s (IPCC’s) Fifth Assessment Report we are exploring concepts of confidence and certainty in climate science. The…Ailie Gallant, Lecturer, School of Geography and Environmental Science, Monash UniversitySophie Lewis, Postdoctoral Research Fellow, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/153482013-08-20T01:19:33Z2013-08-20T01:19:33ZPenguins can’t fly and humans are causing climate change: how scientists build theories<figure><img src="https://images.theconversation.com/files/29551/original/7bfwby92-1376955161.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Maybe humans aren't causing climate change, and maybe penguins choose not to fly.</span> <span class="attribution"><span class="source">Antarctica Bound/Flickr</span></span></figcaption></figure><p><em>In the lead up to the release next month of the Intergovernmental Panel on Climate Change’s (IPCC’s) <a href="http://www.ipcc.ch/scripts/_calendar_template.php?wg=8">Fifth Assessment Report</a> we are exploring concepts of confidence and certainty in climate science – beginning with this, the first of four articles.</em></p>
<p>Penguins can’t fly and a skydiving climate scientist always falls to the ground. In all our minds these are both statements of fact and there is nothing unclear or uncertain about them. </p>
<p>If someone asked, “Why are these facts so?” we would have no difficulty explaining them. It is obvious that penguins cannot fly. They cannot generate enough lift to support their weight. Similarly, of course a climate scientist is going to hurtle toward the ground when jumping out of a plane. It’s called gravity! </p>
<p>We can readily provide explanations of these facts and in our minds they are both certain. Any suggestion that these facts are uncertain, to any degree, would probably get us some very strange looks.</p>
<p>So what about climate change? Why is “certainty” applicable for some scientific theories, such as gravity, but not for other theories such as those that describe a human influence on the climate? </p>
<p>Gravity and the link between anthropogenic carbon dioxide emissions and increasing global temperatures actually have a similarly strong consensus of scientific evidence. Furthermore, science works the same way whether it’s investigating gravity, flying penguins or climate change.</p>
<p>Scientists build theories by gathering and scrutinising multiple lines of evidence, with each new piece of evidence forming part of a bigger puzzle. When enough pieces of the puzzle have been assembled and we can understand the puzzle as a consistent whole, we have developed a scientific theory. </p>
<p>Evidence underpins all scientific theories and guides our understanding on the way our world works. The more evidence we collect, the more consistent, or sometimes inconsistent, our puzzle becomes. It is only with strongly consistent evidence, and very little inconsistent evidence, that a scientific theory is accepted.</p>
<p>A scientific theory is not developed from someone’s hunch. It describes a coherent, evidence-based system of ideas that have been rigorously investigated. But that does not mean that there are zero inconsistencies in the evidence defending a scientific theory. </p>
<p>Let’s hypothesise that you can catch a ball. Scientists would build a body of evidence by throwing you a ball thousands of times. You will probably catch that ball most of the time but there is likely to be the odd occasion when you will not. Those occasions, those inconsistencies, do not disprove that you can catch a ball.</p>
<p>As scientists continue to make observations and the body of evidence becomes more and more consistent, the confidence in a scientific theory increases. But in science, absolute 100% certainty is never obtainable because we can never have an infinitely large body of evidence. The best science can do is to provide virtual certainty by weighing up the consistency using a large amount of evidence.</p>
<p>As with any scientific theory, maybe human-caused climate change is not happening. But then again, <a href="http://youtu.be/9dfWzp7rYR4">maybe penguins are just choosing not to fly</a> because they are afraid of heights. </p><img src="https://counter.theconversation.com/content/15348/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ailie Gallant receives funding from Monash University. She is affiliated with the Centre of Excellence for Climate System Science.</span></em></p><p class="fine-print"><em><span>Sophie Lewis is a Research Fellow at the Melbourne University node of the ARC Centre of Excellence for Climate System Science</span></em></p>In the lead up to the release next month of the Intergovernmental Panel on Climate Change’s (IPCC’s) Fifth Assessment Report we are exploring concepts of confidence and certainty in climate science – beginning…Ailie Gallant, Lecturer, School of Geography and Environmental Science, Monash UniversitySophie Lewis, Postdoctoral Research Fellow, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.