Ten Times Faster Than a Hothouse Extinction — Human Carbon Emission is Worst in at Least 66 Million Years

“If you look over the entire … last 66 million years, the only event that we know of … that has a massive carbon release and happens over a relatively short period of time is the PETM. We actually have to go back to relatively old periods. Because in the more recent past, we don’t see anything [even remotely] comparable to what humans are currently doing.” Richard Zeebe of the University of Hawaii in a recent paper published in Nature.



(Annual human carbon emissions are about 150 times that of all the volcanoes on the Earth, 10 times faster than a hothouse extinction that occurred 55.8 million years ago. Image source: La Rosa Rossa.)

Let’s be very clear. The human fossil fuel emission is outrageous and unprecedented on geological timescales. An insult the Earth has likely never seen before. For the pace at which we are emitting carbon into the atmosphere is just flat out insane. We’ve known this for some time because the best of science can’t find any time in all of Earth’s geological history that produces a rate of atmospheric carbon accumulation equal to the one that’s happening now.

However, a new study recently published in Nature now sheds more light on this rather difficult and scary topic. But in order to find an event that is even remotely comparable to the current human greenhouse gas emission, scientists had to look far back into deep time. All the way back through a period when the last of the Dinosaurs were dying off about 55-66 million years ago.

During this time we find evidence of the most recent Hothouse Mass Extinction Event in the geological record. We call this event the Paleocene-Eocene Thermal Maximum or PETM because it’s an extreme period of rapid warming that occurred at the boundary between these two periods of Earth History about 55.8 million years ago.

The PETM Hothouse Extinction

The PETM was pretty amazingly bad. It set off a mass extinction in the oceans which wiped out half of all shellfish through the varied impacts of anoxia, acidification and coral bleaching. Its heat forcing was enough to completely reverse ocean circulation and set up a stratified ocean state. Peatlands and forests went up in mass conflagrations. Terrible insect plagues swept the globe. The related extreme surface temperatures forced a mass poleward migration and widespread genetic alteration of mammals which were eventually reduced to dwarfism.

Human vs PETM

(Earlier studies estimated PETM emissions rates in the range of 1.7 billion tons of carbon per year. A new Nature study finds PETM emissions to be even lower at 1.1 billion tons of carbon per year. This compares to a current human emission of 10 billion tons of carbon per year. A rate of emission that could jump to as high as 25 billion tons of carbon per year by mid Century unless fossil fuel use is curtailed. It’s worth noting that the ‘slow but steady’ PETM emissions above represent one of the most rapid periods of warming in Earth’s geological history. Image source: Climate Crocks.)

It was a rough and wrenching time of change and difficulty for pretty much all of life on Earth. But what the new study finds and confirms is that the rate of atmospheric carbon accumulation during that extinction period, though enough to cause seriously dramatic climate shifts, was much, much slower than what we see now.

A Human Hothouse Extinction Would be Far Worse

On average, over the PETM extinction event, rates of atmospheric carbon accumulation were found to be in the range of about 1.1 billion tons per year. By comparison, human carbon emissions during 2014 were about ten times this level at around 10 billion tons of hothouse gas hitting the atmosphere. As such, the new study finds that the velocity of the human carbon emission exceeds that of the Paleocene-Eocene hothouse extinction event by an order of magnitude (x10).

Study authors found that the large carbon emission occurred over the course of about 4,000 years. This spike in atmospheric carbon coincided with an approximate 5 degree Celsius spike in global temperatures in the 4,000 to 12,000 year time period. This implies a rate of warming of at most around 0.12 degrees Celsius every 100 years (or as little as 0.04 degrees Celsius per Century). Other estimates put the rate of PETM warming at around 0.025 C per Century. Expected human warming between 1 and 5 degrees Celsius this Century is therefore about 10 to more than 200 times faster than during the PETM extinction event given the best available current scientific evidence.

Such high rates of atmospheric carbon accumulation and related global heating risk generating an event that is outside of any geological context that scientists might use to predict the human warming event’s severity.

“It means we don’t have a really good analog in the past for the massive amount of carbon we’re releasing,” Zeebe said to National Geographic. “Even if we look at the PETM and say the transition to a warmer climate may have been relatively smooth, there’s no guarantee for the future.”

In other words, if you’re adding carbon to the atmosphere at a rate ten times faster than during one of the most remarkable warming events in Earth’s History, then the pace of wrenching geophysical changes and the extinction pressure on organisms is going to be far, far greater. Something that is certainly worse than the PETM and that may even exceed the terrible losses seen during the Permian Mass Extinction if we don’t get a handle on our fossil fuel emissions soon.


Anthropogenic Carbon Release Unprecedented in Last 66 Million Years

A Deadly Climb From Glaciation to Hothouse — Why the Permian Extinction is Pertinent to Human Warming

Earth Hasn’t Heated Up This Fast Since the Dinosaurs’ End

PETM — Global Warming, Naturally

Hat tip to DT Lange

Hat tip to Colorado Bob



Leave a comment


  1. Scary stuff! I collect fossils (including from around the Eocene period) and can easily see what the results of extinction are.
    We need to go beyond fossil fuels quickly (or we will be the fossils)! We are supporting Bernie Sanders for the U.S. presidency. Others are not as passionate about the environment. Republicans deny there is any environmental crisis!

  2. I always like to recommend stuff by Abby Martin, she has a deep incisive look on our world.
    She hits home with this one and the topic fits hand hand with this other excellent blog article from Robert.
    Untouchable Big Oil Threatens All Life On Earth // Empire_File016

  3. Unconstrained access to concentrated easily extractable and usable fossil sunshine brought us to this, like unconstrained access to substrate in the case of other organsms.

    Switching out of fossil energy can buy us some time: http://physics.ucsd.edu/do-the-math/2011/07/galactic-scale-energy/

  4. Great article Robert!

    One thought I had whilst reading it was that at the PETM global temperatures (and C02 levels) started much greater then we are at now. There where no ice sheets and the continents where in different locations. It makes it very difficult to use the PETM as an analog even if the rates of changes in GHG’s were similar (which obviously they’re not).

    • Absolutely. We should really be looking at the Permian if we want to get a better idea. Problem is, it’s so far back in time that it’s tough to get a clear proxy set for it.

      PETM started from a high launching pad — temperature-wise. We are starting during a glacial period during which the Earth had the opportunity to store a lot more carbon. So the issue of carbon store feedbacks is more pressing for us than it would have been during the PETM.

      The issue here is that the current human emission of 10 billion tons C per year has the opportunity to develop more in the way of legs from the global carbon store than the 1.1 billion ton C PETM emission. There weren’t about 1.3 trillion tons of permafrost carbon in the Arctic, for example. And the hydrate store is rather larger than what it would have been during the PETM.

      In layman’s terms — the globe is fully charged with carbon that will be vulnerable to feedback as the Earth warms. This is carbon that was drawn down over the course of the 55 million years from the PETM to now.

      So we should be very keen to get off carbon emissions as soon as possible to keep the Earth System carbon from running away from us and carrying us into worse climate states because we didn’t kick our fossil fuel addiction soon enough.

      • James Cole

         /  March 23, 2016

        “We are starting during a glacial period during which the Earth had the opportunity to store a lot more carbon. So the issue of carbon store feedbacks is more pressing for us than it would have been during the PETM.”
        Great point! And one that really shows how near the edge we are! We took a world loaded with carbon stores, broke it open and burned them like mad, now the rising heat threatens to unlock them all by themselves. What could be worse?

  5. Cate

     /  March 22, 2016

    And just for the record, more unpacking for us lay-folks of the cold blob/cool pool off Greenland…pretty much right on my doorstep. 🙂


    • Those of us near the North Atlantic are going to see some pretty extreme weather over the coming years and decades. Eventually, the impacts will probably jump out of the regional setting. But, yeah, Cate — you’ve got a front row seat. Not quite as bad for you as the UK, though.

      • Cate

         /  March 23, 2016

        Absolutely. The UK is right in the cross-hairs. This past winter was a little foretaste, perhaps.

  6. Hey Robert – got my article published (it relates very much to the material in this article)… you were the first linked url in my article! : http://www.counterpunch.org/2016/03/22/condemning-our-grandchildren-to-a-real-life-video-game/

    • Very well done, David. I don’t understand why Huffpo wouldn’t publish this one. But, hey, maybe counterpunch is the better platform.

      Worth noting that current INDCs put us on a path for 3 C this Century if all the Paris commitments come in. There is no global policy in place that gets us anywhere near to hitting 2 C or less despite that being the stated goal.

      I’ve held fire on Paris because I want to support global policy and build on it. But the summit was not enough. In fact, what it shows to me is that the people driving this nightmare — the fossil fuel industry — has effectively managed to insulate itself from policy action through direct control of many of the lawmaking bodies within States. This control is not universal dominance per sey, but an extraordinary and unprecedented degree of influence which is enough to slow and prevent effective and necessary climate response.

      We saw this in Australia, Britian, somewhat in Germany, in Nevada, in Canada, and in many other regions around the world. Carbon emission reduction policies and renewable/non carbon energy build out continues in fits and starts. Exactly what you would expect in an environment when fossil fuel money sways and confuses appropriate action within legislative and other governing bodies.

      I think the only counter to this is global protest and political action (voting out those who will not adopt effective climate policies or who even refuse to acknowledge the situation). At this time pretty much any fossil fuel infrastructure should be met with fierce opposition, any attempt to slow energy efficiency and non carbon energy development, met with outrage, any attempt to lock individuals into captive carbon consumption met with opposition at every level.

      Your BTS scenario is a bad, bad world. One we do not want to live in. The choices — BTS and severe climate change both end very badly. It’s time we got off the hellish hothouse ride before things really get scary.

      In any case, kudos and well done. I hope people start paying attention. Things just keep getting worse and worse otherwise.

      • hey…if I can be of 1/10th the service that you are through your articles, I’ll be a happy man!

      • climatehawk1

         /  March 23, 2016

        Also critical, IMHO, to elect a Democratic President. Have to either roll back Citizens United or get rid of the charitable tax exemption for the “crank tanks” (the think tanks funded by cranks like the Koch brothers that are really political propaganda mills). Either way, going to need a majority of the Supreme Court to not be right-wing ideologues.

      • Cate

         /  March 23, 2016

        Here is an example of the extent of the influence of the FF industry on govt policy.

        In Canada, the Trudeau govt brought down its first budget today. Instead of cutting FF subsidies aggressively (by one-quarter from the get-go) as they had promised in the election campaign, they have back-pedalled and will leave existing write-offs in place until 2025.

        I think we can safely assume that the FF guys had a few words with the PM and the Finance Minister about this. Thus Big Oil dictates govt energy/economic policy.

        The good news is that $2.9 billion has been allocated over the next five years for climate change—-to “pay for the work on a pan-Canadian framework” or strategy for addressing climate change that would include all provinces, territories, and the fed govt. Some of that funding will also pay for policies…including putting a price on carbon.

        It sounds to me like they’re going to spend a lot of money to have a lot of meetings.

        Anyway, if I’m reading correctly between the lines here, my govt is going to 1. keep subsidising the oil industry while it 2. throws billions into planning to reduce emissions from that same industry.

        Most worryingly in this whole story, there is no sense of urgency here. It’s all patting themselves on the back, oh look how green we are…. indeed. ….as if they have all the time in the world.


      • Cate

         /  March 23, 2016

        More on govt policy aligning with FF industry demands: see how the provincial govt of British Columbia—-astonishingly—positions LNG as a clean, green energy source.

        The federal govt has already given environmental approval for a huge new deep-water port to be built in BC to export LNG from Canada.

        This is all happening as we speak, in complete defiance of all the newest climate change information that is piling up against FF use. Govts in Canada are single-mindedly going ahead with new FF developments. This is the power of Big Oil. This is why we need to protest vigorously and continuously, as Robert said. If we don’t, “irreparable harm” may be all we can offer our children.


        • We need a full-on global blockade of all new fossil fuel projects. A methodology for mustering hundreds of thousands to millions of protesters should be put in place. We can’t allow governments to continue to fail us as they have. BC has basically back-pedaled on its own pledges here and we need to hold them and the Canadian federal government to account.

          At this point we need rapid draw downs in global carbon emissions starting now — not in 2020, not in 2030. Hansen recommends a 6 percent annual reduction in carbon emissions. We’re not going to get that with current global policy so we need an outside push to make that happen. In the 1970s, 150 nuclear power plants were blocked due to a movement that fed on environmental concerns surrounding nuclear power. Well the coal and gas and oil will lock in impacts far, far worse than 150 nuclear power plants if we allow them to keep adding extraction, production, and transport infrastructure for their dangerous products. What we’ll see this Century, if we don’t stop them, is the start of a new hothouse extinction that will likely be worse than all the others. We simply cannot allow that to happen.

  7. climatehawk1

     /  March 23, 2016


  8. anthropocene

     /  March 23, 2016

    After all this bad news a music break is in order I think. Got reminded of this song a few days ago. Unbelievably nearly 30 years old but seems to become more prescient as the years go by. https://www.youtube.com/watch?v=ExynEdyfe9w

  9. redskylite

     /  March 23, 2016

    Thanks for detailing this latest mind blowing study, which is a companion to Dr James Hansen’s now peer reviewed bombshell, issued at the same (or very close) time. The implications of both papers are very shocking indeed. This is a tragic burden to place on our descendants. Every country must do the decent thing and go full speed with the alternatives that we have today, even my own countries PM seems to have finally acknowledged the need, in today’s local news.

    This seems to be a good time to look after the tools we have, including climate scientists, renewables and a new generation of energy expertise.

    “Don’t be fooled by red herrings. Human-caused climate change is real. Attacking the integrity of scientists will not further our understanding of what’s happening to our planet. Similarly, efforts to undermine research findings for ideological reasons are a confusing disservice to the public. Policymakers certainly have a responsibility to exercise appropriate oversight, but thinly veiled political attempts to discredit researchers can have a chilling effect on the scientific discovery that is our best hope for improving people’s lives.”


  10. Andy in SD

     /  March 23, 2016

    Nature will not be able to evolve out of this situation in a successful manner. The time required due to iterations in the genetic lotto to achieve a successful replacement is too long. Also, it will not work due to the rapid pace of change. How can an adaption occur, then achieve a population needed to adapt to the next stair step on this mad trend.

    Successful survivors will be on the order of simpler organisms such as jelly fish, molds and such. Complex organisms will not be able to evolve quick enough.

    Complex organisms have required environments and nutrient sources, these will become less stable. Thus an inability to evolve quickly to the new environment, which is not static but changing further.

    Humans don’t count in this equation. They are intelligent, can migrate, are omnivorous. They will eat the survivors and one another when that is all that is left.

    • Steven Blaisdell

       /  March 23, 2016

      Cormac McCarthy laid this scenario out in “The Road” for those who can listen. Don’t think it’s the only possible outcome; one possibility I’ve thought of is a very, very long term series of stepwise, gradiated climate ‘collapses’ with concomitant human adaptation, mitigations, and death. Maybe some Black Death-like mass die offs, but mostly smaller ‘shrinkings’ and reduced birth rates. Ultimately, perhaps 50,000 years of geologic time scale population collapses and ‘recoveries,’ until the socio-cultural and possibly genetic changes are wired in for survival within the constraints of Earth’s ecology. Hard to say, really.

  11. Colorado Bob

     /  March 23, 2016

    It’s not the change, it’s velocity of the change.

    • Colorado Bob

       /  March 23, 2016

      I can throw a 45 cal, lead bullet at your face. I can shoot you with a 45 cal, hand gun in the face.
      It’s not the change, it’s velocity of the change.

  12. Reply
    • Cate

       /  March 23, 2016

      Yeah, we had the kind of night here in central Newfoundland where you get up in the morning and check your yard to make sure it isn’t full of your shingles…. 😉 But it’s a mite windier down on the Labrador, we hear.

  13. Colorado Bob

     /  March 23, 2016

    If the dinosaur impactor had landed at 2 mph, and not 70,000 mph.

    It’s not the change, it’s velocity of the change.

  14. Colorado Bob

     /  March 23, 2016

    Let’s change the change .

  15. Colorado Bob

     /  March 23, 2016

    One more same album –

  16. – USA 2016 Election Power $$$
    – Worth a quick scan

    How ‘ghost corporations’ are funding the 2016 election

    The 2016 campaign has already seen the highest rate of corporate donations since the Supreme Court unleashed such spending with its 2010 Citizens United v. FEC decision.


    • Colorado Bob

       /  March 23, 2016

      They will gain nothing, . Their collapse is our collapse.

    • Abel Adamski

       /  March 23, 2016

      It began well before. Two good articles on Slate


      Both Parties are guilty, both became panderers

      also on Salon
      Fox News “brainwashed” so many dads: “People are being bamboozled on a massive scale”

      it is truly scary
      A discussion with the producer of a documentary, spread the awareness so that people can regain control of their own lives

      Why it has been such an uphill battle to address the issues we face with the urgency needed

    • There’s a huge amount of fossil fuel company money going into this. And it absolutely has a negative impact on the political process.

  17. – Addiction FF or otherwise) and its casualties.
    – ‘Signed D.C.’ by Arthur Lee is about the heroin overdose death of Love drummer Don Conka. Lee’s simplicity and baleful harmonica are ‘something else’ indeed.

  18. Colorado Bob

     /  March 23, 2016

    Just to be clear, there is not some sweet spot in the future where all the rich get a “Get Out of Climate Change Free”. Card.

    The entire human record has never done this. I see no reason why they can escape.

    • Colorado Bob

       /  March 23, 2016

      We’re all going to hell in a bucket.

      Grateful Dead – Hell In A Bucket 7-7-89

  19. Abel Adamski

     /  March 23, 2016


    A new study has revealed yet another way climate change is going to alter the future of Earth.

    A new study has found that climate change is making it harder for Rocky Mountain forests to recover after a wildfire.

    The regional droughts that are happening partly because of global warming are resulting in big problems after wildfires wipe out forests: growth of new forests is hindered by the fact that post-fire seedlings can’t establish a foothold because of the drought conditions, according to a University of Wisconsin-Madison statement.

    There’s also been an increase in the average distance between burned areas, which provide an addition obstacle to seeds that would be need to replace lost trees.

  20. Jeremy

     /  March 23, 2016

    “The growing season for plants has become a month longer than it was a few decades ago, Met Office figures show. In the last 10 years, the growing season, measured according to the central England temperature daily record, which stretches back hundreds of years, has been on average 29 days longer than in the period 1961-1990, the data show. And while more of the year is warm enough for plants to grow, there has also been a decline in the number of frosty days in recent decades, the Met Office said.”


  21. Spike

     /  March 23, 2016

    Nice graphs of monthly changes 1880-2016

  22. Cate

     /  March 23, 2016

    Bill McKibben in The Nation today, on methane and fracking. There is “no good flavour” of FF. Keep it in the ground, all of it.


  23. Hi Robert-

    I’m just not yet convinced that the PETM went as slowly as the authors claim. The data from individual fossil foraminifera does not seem to me to match their bulk sediment data:

    Like the previous papers on the PETM, the individual fossil foram data records only pre-excursion and post excursion values, with no intermediate values. Certainly individual forams would live quickly and die, I get that. But if the probable methane release occurred slowly, shouldn’t there be some intermediate foraminifer C13 ratio values?

    What I see is not enough data. The other thing I see in these figures is no intermediate values in the foraminifer C13 ratio data.

    • Oh, darn, that image did not post, I guess.

      Here’s the hyperlink:

    • The individual foram data is labeled “Bass River Subb.”. There is one intermediate value in the C13 ratio data, but it occurs higher in the sediment, supposedly after a much higher value at the post excursion C13 ratio. So, looking at the data, it seems inconclusive to me, and looks like not enough data.

    • Well, Leland, the volcanism during the period is pretty clearly documented, we have initial proxies showing top down ocean warming. The foram events would jibe well with a later PETM methane pulse at ocean bottom levels. However, using forams as a proxy presents problems due to the fact that response would be to an ocean bottom carbon pool. So you’re talking about impacts in the ocean bottom region where the forams live which was a likely feedback to the overall volcanic-related forcing. So basically what I’m saying is that a single foram layer showing this C13 response does not a global proxy make. Meanwhile, the overall science shows repeated indicators in the 3,000 to 20,000 year range. So regardless of whether or not you’re convinced, the broader science has a moderate to high certainty on the above timeframe which would require numerous sets of empirical evidence from multiple research bodies to adequately refute.

      Overall, PETM methane response would be less than during a post glacial warming due to a loss of a decent portion of the CH 4 charge. Methane response would occur at a deeper level of the ocean and have less ability to energetically move through the water column. Lower initial deeper ocean carbon saturation would also be a limiting factor.

      The fact that mass extinction did initiate at the deep ocean level and move somewhat up the water column is a possible indication of a degree of CH 4 response and related ocean anoxia due to stratification. However, what likely reduced the overall feedback was the fact that PETM began at the end of a long warming period. This likely limited global carbon store feedback response — thereby preventing PETM from ranking among the other top 4 hothouse extinctions.

      For my part, I’m not convinced that cherry picking specific studies and arguing from a single frame of reference will produce a better understanding of what exactly happened during this key time period. I am not convinced that making blanket assertions based on a minor pool of study evidence is a good way to move forward either. The study data you indicate is interesting. However, there are a number of reasons, as noted above, why proxy foram data would behave in this fashion.

      This, of course, does not eliminate the possibility that a methane pulse occurred. In my opinion, it’s possible that one of at least moderate force did arise. And, in my opinion, it’s likely that these kinds of feedbacks do play a role in mass extinction events, stratification, and the development of Canfield Ocean states during major hothouse events. But honing in on this as a single cause in thesis proof/refutation manner is a myopic way to move forward. Systemic understanding of the PETM should at the very least incorporate Indian subcontinental volcanism — which we have quite a mass of evidence for. In addition, the large peatland and forest conflagrations during the time also likely played a role. The more we look at these hothouse events, the more, to me at least, it looks like a hothouse death by a thousand forcing and amplifying feedback cuts.



      • Oh, great, thanks for the information.

        The reason I focus on the foraminifer isotope data is that I think that it is good data, and pretty much free of bias. It should be possible to determine carbon and oxygen stable isotope ratios with a high degree of precision by mass spectroscopy. So, I trust the carbon and oxygen isotope ratios, but not much else about this data.

        Looking again at the graph in the Nature paper, the value I took to be an intermediate value is actually an average value, in the C13 ratio data. The open diamonds are what I should be looking at, not the filled ones. Once again, there are no intermediate values in the C13 carbon isotope ratio data, and counting the data points, I see less than 20 data points.

        Most of the other data appears to me to have a systematic bias toward overstating the duration of the change. What I mean by that is that is that there is some degree of physical mixing during the sedimentation process, that would tend to smear out the duration of the change. Organisms also stir the sediment with their activities, at least to some degree, I think. So, I trust the isotope ratios of the singe foraminifers, but have some doubt that the measurements of the forams or sediment particles physical position within the sediment column are precise. I don’t really trust the isotope ratio measurements of the bulk sediment, because of the physical mixing issue, potentially blurring the duration of the change.

        The position of the samples in the sediment column is represented as absolute, without error bars. But it is apparent by looking at the data that some mixing in position around the time of the excursion has occurred – and that is the only region in the data when physical mixing would be apparent. Some values appear to be displaced in position (and so in time) by up to about 0.1 meters around the C13 isotope ratio excursion.

        I also don’t really trust the mathematical sophistication of the paper, working on what seems to me to be not enough unbiased data. With enough data, it should be possible to determine the duration of the change mostly just by tallying data, and not by any sort of sophisticated mathematics or modeling. Many scientific fads and false claims have come from applying sophisticated mathematics to data very near the limit of detection or statistical significance, or data that has a systematic bias, as you know.

        It should be possible to do an order of magnitude estimate, just by graphing the data.

        What I will do, when I get the time, is look at all the foram carbon isotope data I can find, and look for intermediate values. Then I’ll just multiply the total time interval for each data set by the ratio of the number of intermediate values to the whole, to get my unbiased order of magnitude estimate for the duration of the event assuming a constant foram population.

        What I still see in the data is no intermediate values in the C13 carbon isotope ratio data for individual foraminifers. This suggests an abrupt change, consistent with an abrupt methane release.

        • So we should remember that bottom dwelling forams are more likely to show bias to local swings that may not be representative of the whole water column, much less the atmosphere. Current forams in or near methane seeps would show a similar bias. In addition, the stratified ocean state during the PETM would have produced exaggerated swings that were more common for the period. Finally, we have other foram based studies from PETM that do not produce these numbers. These and other reasons provide cause for caution when interpreting this data set.

      • Hi Robert-

        Looking at this data set, the foram C13 data looks good. If the core was near a methane seep, like you say, it’s hard to see why the C13 data would show a constant value, and then right at the time of the PETM, abruptly shift to another constant value. The oxygen isotope data shows a similar disruption The data is consistent with an abrupt carbon (and oxygen) isotope ratio excursion, precisely at the time of the PETM, and the odds of that occurring at random are very low. Several previous papers have also used foraminifer data, and have seen precisely the same pattern.

        If the probable methane release was gradual, and was released over several ocean mixing times, there would almost certainly be intermediate values.

        No, Robert, the C13 data is not randomly scattered, the way it would look if it was corrupted by local methane seeps. It shows an definite pattern – a baseline, then an abrupt shift to a new baseline. And it shows an abrupt shift with no intermediate values, suggesting a sudden massive methane release. Other mass extinction events, at many sites, as you know, show very similar sudden carbon and oxygen isotope ratio excursions, precisely at the time of the mass extinctions. The oxygen isotope ratio excursion is consistent with an increase in temperature, as would be expected if there was a sudden massive methane release. The bulk sediment also shows the same carbon and oxygen isotope ratio pattern. I don’t trust the bulk sediment data to be sharp enough and undisturbed enough to determine the duration of the mass extinction, but it certainly shows the same general pattern as the foram data, and itself shows a shift in isotope ratios, both in the
        C13 carbon isotope ratio data and in the C16/C18 oxygen ratio data, and shows it at the same time as the foram data.

        If the foram populations crashed at the time of the methane release, that might explain the abrupt shift. But nobody I know of is claiming that. And once again, simply collecting lots of data and counting number of forams at each level in the sediment column would likely show if there was a population crash at the time of the mass extinction.

        Another approach to the physical mixing problem would be to find a location in which sediment was deposited rapidly enough to make thick sediment beds. That is the approach that Paul Wignall used for the End Permian, and by finding thick sediments in Greenland he was able to find a tens of meters thick bed that spanned the entire mass extinction. So he was able to develop a detailed chronology for the entire mass extinction, which had several phases and several abrupt carbon isotope excursions, spanning an 80,000 year time span.

      • Hi Robert –

        This paper seems to have thicker sediment beds, and is based on carbonate nodules in terrestrial soils, so it is not perturbed by species population crashes.

        The authors claim that these carbonate nodules are obviously formed in-situ, and therefore do not suffer from the physical mixing problem. With their higher resolution record, covering tens of meters in depth, they claim a previously unrecognized Pre-Onset Excursion (POE) in the C13 ratios, lasting for about 1000 years, followed by a hiatus and then a rapid jump to the full blown PETM, with the jump to the PETM lasting around 1000 years or less.


        “Thus, the BBCP record suggests that rates of release during the PETM were probably within an order of magnitude of, and may have approached, the 9.5 Pg yr−1 associated with modern anthropogenic carbon emissions 5.

        The rates and pattern of release inferred here are consistent with evidence from single-specimen analysis of foraminiferal tests 28, but contrast with much lower rates (<0.3 Pg yr−1) and continuous release inferred from methane-release simulations tuned to marine-margin records 4 that may be affected by time-averaging 9.

        Thus, our findings re-establish the possibility that the PETM may be a strong analogue
        for anthropogenic global change in terms of both magnitude and rates of change."

        Here's what they say about methane from the hydrates:

        "If this is the case, the PETM may provide geologic evidence for a strong clathrate feedback to global warming at∼103 -year [1000 year – LP] timescales, meaning that the long-term response of clathrates to anthropogenic warming deserves further consideration 27."

        The authors' approach to finding thick sediments seems good. There is plenty of carbonate to take large samples, I think, and that is good, and many data points can be gathered. As Robert points out, this paper samples the atmospheric carbon reservoir, and that is more certainly linked to hothouse extinction events than is the oceanic carbon reservoir.

        But in their data showing the onset of the full blown PETM, there are also no intermediate C13 ratio values, between the baseline and the post excursion values. So 1000 years may still not be a short enough time scale for the abrupt main isotope excursion.

        The reason that some of us focus on possible methane releases is that really abrupt methane releases perhaps like these could possibly kill human society as we know it. Certainly there were other things going on, during the PETM- volcanism and so on. But if a strong positive feedback driven methane release from the clathrates occurs, very little else might matter.

  24. June

     /  March 23, 2016

    The graph showing the difference in emission rates brings home, like a punch in the gut, the unprecedented nature of the changes we face. It is something I think the general public really doesn’t get.

    Jeff Masters and Bob Henson have a new blog post on the new Global Sustainability Institute report on coming food shortages and political instability in a BAU scenario. Great but jarring blog title.

    Avoiding a Soylent Green Future by 2040


    • – A good link.Thanks

      ‘A non-sci-fi computer model being developed by the Global Sustainability Institute at the UK’s Anglia Ruskin University predicts that catastrophic food shortages, triggered by a combination of climate change, water scarcity, energy crisis, and political instability might lead to a virtual collapse industrial civilization by 2040. The model explores short-term scenarios of policy decisions by simulating social-economical-environmental systems, including the impact of climate-induced drought on crop failures and food prices. The model was successfully used to simulate the multiple factors–including the great Russian drought of 2010–that made the 2011 Arab Spring uprisings more likely. ‘

    • BAU = Business As Usual is correct as most FF emissions are commerce $$$ driven.

  25. Cate

     /  March 23, 2016

    Question (possibly dumb): reading that Jason Box suggests a 6% reduction in emissions will help to keep levels down—over five years, would the progression then be arithmetical, ie, five times 6% = 30% over five years, or would it be more like reverse compound interest, so 6% annually on what remains, for a rather smaller percentage over five years?

    In any case, what are the chances we will be anywhere near that globally, in five years from now?

    • Ken Barrows

       /  March 23, 2016

      Like reverse compound interest. It means, under the Rule of 72, that emissions are halved in 12 years. Halved again in the following 12 years.

      • Cate

         /  March 23, 2016

        Ken thanks…so in about 25 years at a constant 6% rate of reduction, emlssions would drop to about a quarter of what they are now….roughly…? Is that about right?

  26. – A very appropriate video log by Jason Box re a subject of importance here.

    North Atlantic freshening from land ice melt, cold blob, stronger storms

  27. Reply
  28. Reply
  29. Reply
    • – Univision best at 7.1%

      • Appreciate the fact that Bernie keeps bringing it up in debates, interviews and on his website including the latest in the Times
        (Scientists Warn of Perilous Climate Shift Within Decades, Not Centuries) Along with the fact that he is the only candidate (EVER) to not be beholden to FF industry.
        I won’t keep repeating my thoughts and links that make our choice very clear in this presidential “election”—– will leave it at that.

      • Yes, Bernie needs to bang the ‘climate’ gong as loud as he can.

    • Should be at least 1 in 10. The major networks really need to buck up. But it’s not a surprise. Climate change keeps getting pushed into the underground.

  30. – For Bob, et al.

    These Eerie Images Show How Humans Reshaped the West
    Unlike Ansel Adams’ romantic and iconic images, these have an uneasy quietness.

    Just as no photo really does justice to the majesty of a beautiful landscape, an online gallery like this doesn’t quite convey the depth of work in David T. Hanson’s book, Wilderness to Wasteland (Taverner Press). He goes deep and wide in his view of the American West.

  31. James Cole

     /  March 23, 2016

    Who else believes that “the Powers that Be” have written off stopping climate change with cut backs of fossil fuels? Instead these mad men may be hanging their hats on climate engineering. I know it sounds mad, but how much madder is what we seem to be up to right now.
    Something like 5 or 6 of the world’s most profitable corporations are Oil and Gas producers. They and their political friends have only one know plan, “Continue to make as much money as possible”.

    • Exxon CEO recently issued a statement to the effect of ‘climate change is something we can engineer our way out of.’ To me this sounds like a reference to geo-engineering.

      • – Exxon CEO is just blowing colored smoke… usually where the sun never shines.:) They’ve lost all credibility as far as I’m concerned.

  32. – USA Weather – Side by each

    Zack Labe ‏@ZLabe 55m55 minutes ago

    #MODIS (Terra) also showing clear smoke plumes w/ large wildfire near OK/KS border. Denver blizzard just to the west

  33. Reply
  34. Great information! Unfortunately, it will have to battle with the human capacity for denial and the determination to continue making money, carbon emissions and all. If the worst happens and evolution starts again, I hope it has a better outcome than H. sapiens (who was so incorrectly named).

  1. CO2 Atmosférico Aumenta a uns Extremos 409,3 Partes por Milhão
  2. Key Hothouse Gas to Rise at Record Rate, Hit Near 408 Parts Per Million in 2016 | robertscribbler
  3. May Marks 8th Consecutive Record Hot Month in NASA’s Global Temperature Measure | robertscribbler

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