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As carbon dioxide hits a new high, there’s still no Planet B

On May 9, 2013, the National Oceanic and Atmospheric Administration in the US recorded CO2 levels in the atmosphere at of 400 parts per million. This signifies a return to the atmospheric conditions similar…

The extreme rate at which greenhouse gases and temperatures are rising is leading to extensive fires. AAP Image/Kim Foale

On May 9, 2013, the National Oceanic and Atmospheric Administration in the US recorded CO2 levels in the atmosphere at of 400 parts per million. This signifies a return to the atmospheric conditions similar to those of the Pliocene, which ended about 2.6 million years ago.

The tropical Pliocene

Global Pliocene temperatures were on average about 2–4°C warmer than pre-industrial temperatures. Those temperatures drove an intense hydrological cycle with extreme evaporation and precipitation. It led to extensive rain forests, lush savannas (now occupied by deserts), small ice caps (about two-thirds of the present) and sea levels about 25 meters higher than at present.

Life abounded during the Pliocene. But such conditions mean agriculture would hardly be possible. The tropical Pliocene had intense alternating downpours and heat waves. Regular river flow and temperate Mediterranean-type climates which allow extensive farming could hardly exist under those conditions.

After the Pliocene, the earth’s climate shifted gradually into the Pleistocene. During the following 2 million years, glacial-interglacial periods required species to adapt to rapid climate shifts. These shifts included abrupt warming events actually within glacial periods, where regional warming by several degrees occurred over periods as short as several decades to a century.

Basic physics and chemistry, as well as the geological record, tell us that greenhouse gases are the key factor determining the current climate trend. Current greenhouse gas rise rates exceed those of the Pleistocene cycles by more than an order of magnitude. These rates, which during 2012-2013 reached 2.89 ppm CO2 per year, exceeding any recorded for the last 65 million years, would hardly allow species to adapt to changing climate conditions (see Figure 1).

Figure 1 The current rise in greenhouse emissions is the highest in the past 65 million years, way higher than during the rapid warming periods known as Dansgaard-Oeschger cycles (D-O cycles). Andrew Glikson

Will this mean mass extinction?

The current CO2 ppm per year rise rate surpasses CO2 and temperature rise rates during mass extinctions about 55 million years ago and 65 million years ago.

Fifty-five million years ago, large-scale release of methane drove atmospheric CO2 to near-1800 ppm and temperature rise to about 5°C over a period of 10,000 years. (That’s 0.18 ppm CO2year and 0.0005°C/year.)

Sixty-five million years ago, the K-T asteroid impact resulted in a rise of more than 2000ppm CO2 and about 7.5°C over a period of about 10,000 years (or about 0.2 ppm/year and 0.00075°C per year). About 4500 billion tons of carbon was released from impacted carbonates and shale, from ignited bushfires and from ocean warming. The CO2 rise rate was an order of magnitude lower than current rate of 3ppm/year.

What will the world look like?

The current rise in greenhouse gases is enhancing the hydrological cycle, with ensuing floods, heat waves and droughts.

If we burned all the earth’s known fossil fuel reserves it would lead to atmospheric CO2 levels of around 800 to 1000ppm, high or total melting of the polar ice caps, sea level rise on the scale of tens of meters and disruption of the biosphere on a scale analogous to recorded mass extinctions.

At the same time as CO2 emissions, sulphur dioxide (SO2) is being released, mainly from coal burning. This sulphur is increasing the reflection of the atmosphere and thus regulates changes in temperature, as shown in Figure 2 for the periods following 1950, 1975 and 2001. The trend of rising temperatures slowed in 1950 and 2001 when sulphur emissions increased. Likewise, when clean air policies were introduced in 1975, slowing sulphur emissions, a fast-rising temperature trend resumed. The current rise in coal burning and sulphur emissions are locking the world into a Catch-22 cycle.

Carbon emissions may be self-limiting. It is likely that, before atmospheric CO2 reaches 500ppm, extreme weather events would disrupt industrial and transport fossil fuel-combusting systems enough to lead to reduction of emissions. However, the feedback processes like methane release, forest bushfires and warming oceans will drive CO2 levels further.

Sulphur emissions have moderated temperature rises Temperature: GISS/NASA; Sulphur: SJ Smith

When will we act?

The land, oceans and biosphere are now in extreme danger, but it doesn’t seem to be driving the global community to the urgent measures required for a meaningful attempt to arrest the current trend. With few exceptions, the accelerating rate of atmospheric CO2 hardly rates a mention on the pages of the global media, preoccupied as it is with short-term economic forecast, daily exchange rates, share market fluctuations and sports results.

In Australia the language has changed from “the greatest moral issue of our generation” to controversy over a “carbon tax”, diverting the public attention from the climate to a hip-pocket nerve. While we debate the ways to bring about a meaningless 5% reduction in local emissions, we simultaneously develop infrastructure to export hundreds of millions of tons of coal. It all ends up in the same atmosphere.

As Carl Sagan reminded us, on seeing a photograph of Earth taken from Voyager 1 as it left the Solar System

That’s here. That’s home. That’s us. On it everyone you know, everyone you love, everyone you’ve ever heard of, every human being who ever was, lived out their lives … Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity — in all this vastness — there is no hint that help will come from elsewhere to save us from ourselves.

The pale blue dot of our Earth has no replacement. Voyager 1, NASA

Join the conversation

43 Comments sorted by

Comments on this article are now closed.

    1. Gerard Dean

      Managing Director

      In reply to Mike Hansen

      Mr Hansen,

      The old JetA1 burner himself, lecturing others to cut fossil fuel usage.

      There is a word for that.

      Gerard Dean

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  1. Mark Pollock

    Analyst

    So, if I get this right, CO2 levels are now as high as they were during the Pliocene. And temperatures during the Pliocene were 2-4 degrees higher than they are now.

    So maybe CO2 levels have got nothing to do with global temperatures. Maybe something else is responsible for the gentle warming we have experienced since we moved out of the little ice age?

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    1. Mark Pollock

      Analyst

      In reply to Matthew Albrecht

      Matthew, I think the atmosphere, maybe not the oceans responds pretty quickly to changes in the thermodynamic stuff. You might have noticed that it's sometimes warmer during the day than at night and how if a cloud comes over during the day it gets colder and if a cloud comes over at night it gets warmer.

      And as I understand, those extra CO2 molecules start work straight away. They don't hang around. Once they are up in the troposphere they start grabbing those IR photons pretty damn smart. Why would there be any lag?

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    2. Sean Lamb

      Science Denier

      In reply to Mark Pollock

      Dr Glikson will doubtlessly be along soonish to say it is all because it is being masked by SO2.

      Is Dr Glikson simply being disingenuous or is really ill-informed about the widely understood mechanisms of paleoclimate reconstructions?
      To refresh his memory I would invite him to read this classic paper
      http://www.nature.com/nature/journal/v329/n6138/abs/329408a0.html
      "Over this timescale a high correlation is found between CO2 concentrations and Antarctic climate, with significant oscillatory…

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    3. Matthew Albrecht

      Postdoctoral Researcher at Curtin University

      In reply to Mark Pollock

      I'd rather not speculate, and it not being my area, but if the oceans and atmosphere are linked then I can see that causing a potentially significant lag between temperature and CO2. But that's just one reason, there's probably many others.

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    4. Mark Pollock

      Analyst

      In reply to Matthew Albrecht

      Speculate away! Everyone else does. And don't worry about it not being your area. Didn't stop Tim and Al making a motza out our it did it now? I don't think there is any doubt about the ocean atmosphere temperature link. Anyone who has lived by the coast would know this. Getting CO2 IR absorption into the picture is a trickier proposition.

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    5. David Arthur

      resistance gnome

      In reply to Mark Pollock

      Mark, oceans have something like 1000 times the heat capacity of the atmosphere. Therefore, if atmosphere and oceans were heating uniformly, we'd expect ~99.9% of all thermal energy retained in the earth's climate system to be reporting to the oceans.

      What's happened instead is, the atmosphere has responded more rapidly over the last few centuries to very rapid perturbation.

      You're an analyst, I'm sure you're capable of writing a system of coupled differential equations.

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    6. Mark Pollock

      Analyst

      In reply to David Arthur

      That's a very big "if". It's interesting that you are pushing the starting point of AGW back a "couple of centuries" to a period of relatively low atmospheric CO2 concentrations. Also interesting is the introduction of the idea the energy is now being transferred to the oceans were previously it went into warming the atmosphere. Makes me think that maybe the science isn't quite so settled.

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    7. George Takacs

      Physicist

      In reply to Mark Pollock

      Mark,

      Matthew's suggestion was correct. The heating response is instantaneous, but not the temperature response. If you reduce, instantaneously, the rate at which any system with a constant heat input can lose heat to its surrounds, then the temperature will rise over time. As the temperature rises the rate at which the system loses heat to its surrounds increases. All else being equal, eventually the system will reach equilibrium at a new higher temperature.

      For the case of pur planet, all…

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    8. Gary Murphy

      Independent Thinker

      In reply to George Takacs

      The increase in radiative forcing caused by extra greenhouse gases will cause the earth to absorb more heat and continue to do so until it rises in temperature enough so that it radiates enough outgoing heat to again match the incoming radiation. This will take a very long time.

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    9. Mark Pollock

      Analyst

      In reply to George Takacs

      George, I do not suggest that this process does not happen. Nor that it happens quickly.

      How the mechanism actually operates is likely to be fiendishly complicated. It's another example of how the science isn't settled at all. It also undermines the doomsayers' claims that the earth's atmosphere will experience rapid and extreme heating over the coming century.

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    10. Alice Kelly
      Alice Kelly is a Friend of The Conversation.

      sole parent

      In reply to Mark Pollock

      "gentle warming we have experienced since the little ice age", soothing words, what a shame about the rapid increase since the 1970's. I suppose we can wait and see what happens when we lose most ice in the arctic and the west antarctic and greenland. Wont take long for the gentle warming to get rid of a few bergs.

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    11. John Campbell

      farmer

      In reply to Mark Pollock

      More CO2 = more heat being trapped by the Earth

      More CO2 over an extended period = much more heat and higher temperatures.

      Surely all you kindergarten types can understand this?

      If not I'll use a simple analogy - a bath with a tap running will collect more water over a longer time than a shorter one.

      Higher temperatures? You would simply need to wait, even without more CO2 being poured into the atmosphere at a rate 200,000% faster than would be occurring naturally.

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  2. Mark Pollock

    Analyst

    I really love the scale on the the scary global land ocean temperature index. Climate science at its best. Full degrees for the cold bits and tenths for the Gaia destroying warm bits. Gotta get that trend up anyway you can. I wouldn't let the kids look at it though. Might give them nightmares.

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    1. Mark Pollock

      Analyst

      In reply to Matthew Albrecht

      That's the biggest link I've ever seen. Couldn't he just have posted an honest graph? If you've got a decent argument do you need to lard it like that?

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    2. Mark Pollock

      Analyst

      In reply to Matthew Albrecht

      I can see from the link that the minima are around 0.4 degrees. The minima on the graph on the post are clearly 4 degrees. Is this just another example of climate science incompetence? It's got nothing to do with image resolution.

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    3. Matthew Albrecht

      Postdoctoral Researcher at Curtin University

      In reply to Mark Pollock

      If you look at the second image in my extraordinarily long link you'll see exactly the same image as the one used in this piece but for the difference of the decimal point in front of the negative numbers being cut off (due to image resolution).

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    4. Mark Pollock

      Analyst

      In reply to Matthew Albrecht

      Yes Matthew, I can see that. Thank you. I have bookmarked the page as it looks useful. Meanwhile, what's a decimal point here or there for a climate scientist? It's all settled isn't it? Nothing could go wrong could it?

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    5. Gary Murphy

      Independent Thinker

      In reply to Mark Pollock

      It's just a typo (the dots on the negative bits are missing) - the axis is uniform.
      I think you owe someone an apology.

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    6. Liam J

      logged in via email @gmail.com

      In reply to Gary Murphy

      Anthropogenic warming deniers don't do apologies or explanations, they're too busy looking for the next punctuation error.

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    7. Felix MacNeill

      Environmental Manager

      In reply to Matthew Albrecht

      Matthew, he has no point, just waffle degenerating into insults when he's challenged. Ignore the troll.

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  3. Mark Pollock

    Analyst

    Even with its distorted scale, the temperature graph clearly shows the flatline over the last 15 to 20 years. I know, I know, the author talks about the white knight of sulphur emissions which is supposed to save the maiden (model) of doom from being totally wronged. There is always something to keep the settled science on track.

    I also really liked the suggestion that the longed for, projected, deeply desired climate disasters might actually prevent the scarifying great frying. Industry and transport will be destroyed and we'll all be saved! Hallelujah!

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    1. Mark Pollock

      Analyst

      In reply to Mike Hansen

      It's not a logarithmic scale. It's a mistake. Thank you for the abuse. Most kind. Thank you for the very useful links. Dunning-Kruger again. Once again I am amazed by your stellar intellect and linking abilities.

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    2. Liam J

      logged in via email @gmail.com

      In reply to Mark Pollock

      It IS a logarithmic scale Mark, it seems you are a personal error denier as well, no wonder you hate science.

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    1. David Arthur

      resistance gnome

      In reply to Mark Pollock

      Mark, you seem to be here to be abusive only.

      If you had the brains, guts and personal honesty you'd have a look at the links provided - there isn't enough room on this page for Dr Glikson to copy and paste their entire contents for you - but maybe that would force more introspection than you're willing to contemplate.

      Anyway, here's a summary of why global warming is an unavoidable truth of this world.

      Earth is warmed by absorption of short wave sunlight. Because of this, Earth's temperature…

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    2. Mark Pollock

      Analyst

      In reply to David Arthur

      The problem here is that we have an indisputable observation. The earth has been getting warmer. No one doubts that. The real argument is why? By how much and will it be problematic?

      I appreciate that you have taken the time to describe the basic physics but you are still trying to establish causation from a correlation.

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  4. Gerard Dean

    Managing Director

    Glikson, you just don't get it, do you.

    You state that, 'the accelerating rate of atmospheric CO2 hardly rates a mention on the pages of the global media, preoccupied as it is with short-term economic forecast, daily exchange rates, share market fluctuations and sports results.'

    The media is preoccupied by the society it reports on, like a mirror. Don't blame the mirror - blame the reflection that is us. Look around at your friends driving their new 4 wheel drives and flying to Aspen for skiing…

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    1. Gary Murphy

      Independent Thinker

      In reply to Gerard Dean

      "Not one. And should indicate to you that you are preaching to the wind."

      Now your ridiculous overgeneralisation has reached totality. I do many of these things and a lot of other people do too.

      Mr Dean seems to think it is morally superior to pretend there is no problem than to admit you are part of it.

      A very courageous position - the Anzacs would be proud.

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  5. Leigh Burrell

    Trophy hunter at Trophy hunter

    "The extreme rate at which greenhouse gases and temperatures are rising is leading to extensive fires."

    Atmospheric temperatures aren't rising at all. We're told the heat is going into the ocean. Is the ocean heat causing these extensive fires despite failing to heat the atmosphere? Frankly, that seems far-fetched.

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    1. Gary Murphy

      Independent Thinker

      In reply to Leigh Burrell

      It is the drier conditions that are leading to more and more intense fires. And the higher incidence of more extreme heat waves.

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