Study: Extraterrestrial impact preceded ancient global warming event


Troy, N.Y. — A comet strike may have triggered the Paleocene-Eocene Thermal Maximum (PETM), a rapid warming of the Earth caused by an accumulation of atmospheric carbon dioxide 56 million years ago, which offers analogs to global warming today. Sorting through samples of sediment from the time period, researchers at Rensselaer Polytechnic Institute discovered evidence of the strike in the form of microtektites – tiny dark glassy spheres typically formed by extraterrestrial impacts. The research will be published tomorrow in the journal Science.

Microtektites as first seen in a sediment sample from the onset of the Paeocene-Eocene Thermal Maximum. CREDIT Rensselaer Polytechnic Institute

Microtektites as first seen in a sediment sample from the onset of the Paeocene-Eocene Thermal Maximum.
CREDIT Rensselaer Polytechnic Institute

“This tells us that there was an extraterrestrial impact at the time this sediment was deposited – a space rock hit the planet,” said Morgan Schaller, an assistant professor of earth and environmental sciences at Rensselaer, and corresponding author of the paper. “The coincidence of an impact with a major climate change is nothing short of remarkable.” Schaller is joined in the research by Rensselaer professor Miriam Katz and graduate student Megan Fung, James Wright of Rutgers University, and Dennis Kent of Columbia University.

Schaller was searching for fossilized remains of Foraminifera, a tiny organism that produces a shell, when he first noticed a microtektite in the sediment he was examining. Although it is common for researchers to search for fossilized remains in PETM sediments, microtektites have not been previously detected. Schaller and his team theorize this is because microtektites are typically dark in color, and do not stand out on the black sorting tray researchers use to search for light-colored fossilized remains. Once Schaller noticed the first microtektite, the researchers switched to a white sorting tray, and began to find more.

At peak abundance, the research team found as many as three microtektites per gram of sediment examined. Microtektites are typically spherical, or tear-drop shaped, and are formed by an impact powerful enough to melt and vaporize the target area, casting molten ejecta into the atmosphere. Some microtektites from the samples contained “shocked quartz,” definitive evidence of their impact origin, and exhibited microcraters or were sintered together, evidence of the speed at which they were traveling as they solidified and hit the ground.

Atmospheric carbon dioxide increased rapidly during the PETM, and an accompanying spike in global temperatures of about 5 to 8 degrees Celsius lasted for about 150,000 years. Although this much is known, the source of the carbon dioxide had not been determined, and little is known about the exact sequence of events – such as how rapidly carbon dioxide entered the atmosphere, how quickly and at what rate temperatures began to rise, and how long it took to reach a global high temperature.

One clue can be found in a sudden shift in the ratio of carbon isotopes (atoms containing a number of neutrons unequal to the protons in their nucleus) in certain fossils from the time period. In particular, Foraminifera, or “forams,” produce a shell whose chemistry is representative of atmospheric and ocean carbon isotopes. The research team initially set out to examine the ratio of carbon isotopes in Foraminifera fossils over time, to more closely pinpoint events during the PETM.

“In sediment records, when you look at the ratio of carbon-12 to carbon-13 in a particular species, you see that it’s stable and then it abruptly shifts, wiggles back and forth and slowly returns to pre-event values over hundreds of thousands of years,” Schaller said. “This evidence defines the event, and tells us that the atmosphere changed, in particular adding carbon from a source depleted in carbon-13. A comet impact on its own may have contributed carbon to the atmosphere, but is too small to explain the whole event and more likely acts as a trigger for additional carbon releases from other sources.”

As a source of fossils, the team used sediment cores – cylinders of sediment extracted vertically from sediment deposits with a hollow bit – known to correspond to the time period of the PETM. Sediments near the top are more recent, those further down are older, and signature layers indicating known events are used to calibrate the timescale represented in the sample. The team chose cores from three sites – Wilson Lake and Millville in New Jersey, and Blake Nose, an underwater site east of Florida – known for a rich sedimentary record of the time period.

As Schaller tells it, the discovery of microtektites was “completely by accident.” Ordinarily, the team passes samples through sieves of various sizes, to isolate samples most likely to contain forams. The tektites, which are smaller than most forams, would have been largely removed in this process.

“We were having lousy luck looking for forams, and I was frustrated. I went to the lab and dumped a sample on the sorting tray without sieving it, and there it was,” Schaller said. “It was a stunning moment. I knew what I was looking at was not normal.”

Once the team made the discovery, they obtained a sample from a fourth site – Medford – where the unit is naturally exposed at the surface, to rule out the possibility that the samples had been contaminated by the drilling process. The Medford samples also contained microtektites.



98 thoughts on “Study: Extraterrestrial impact preceded ancient global warming event

  1. Good News.

    I was sure Michael Mann would nature-trick the blame onto Exxon Mobile for that warming as well. He is not dead so he still has time to do that and get another Nobel Prize.

    • Of course the point of this study is to show that the previous environment was caused by an impact and the current is caused by us. Conveniently.

      Solicited study imo

      • Yes. I totally agree. Also note the “completely by accident” AKA “we weren’t looking for this. Honest!” I’ve seen that before.

        This will be presented as some sort of “proof” that current warming is man-made because “it can’t be anything else”. I’ve seen that before too.

      • No, to judge from the text of the press release, the aim here was to say CO2 was X ppm at this time and look how hot it was, ignore that the earth is generally cooling on the geological scale. They got distracted along the by some real science.

        At 56 million years ago , I doubt that they would have enough time resolution to establish the relative timing of the two changes, so they would almost certainly have done an Al Gore and presented the CO2 as the cause of the change in temperature, not the other way around as seen when you can resolve the difference.

        … a rapid warming of the Earth caused by an accumulation of atmospheric carbon dioxide 56 million years ago, which offers analogs to global warming today

        So before they have the done the study or any data they have already made assumptions about cause and effect and are drawing “analogies” with a very different situation today when we are dumping CO2 into the atmosphere. Of course this may be some added spin by “climate communications” student writing the press releases.

        It is unclear whether they still intend to study CO2 temperature relationship from this period.

    • Well they made it through three real words, before arriving at the first need for some weasel room.

      Of course those three words; ” A comet strike ” don’t convey a great deal of information; well there’s no verb. But finally, we get to “may” which introduces the fundamental concept of doubt.

      So “may” is one of the options introduced, as “may not” would seem to be an equal degree of uncertainty.

      Just what earthly relevance this has to anything today, is just as unknown.


  2. Earth was already much warmer than now, by about ten degrees C, and held a lot more CO2 in its atmosphere, before the PETM spike. The polar ocean gain was around two degrees C.

    • Actually fred it is prone to runaway. It tends to max out at about 10c warmer. It has done this several times.
      Whatever causes it is more influential than the Milankovitch cycles. Over long periods – tens of millions of years – it tends to flop up and down between hot and cold.

  3. Fascinating. I’ve always felt that the previous explanations of the PETM were forced and labored. This idea of an impact makes much more sense, as I could never figure what would suddenly change everything.

    From my limited reading, I’ve long thought that the sequence of events involved a massive disruption of the methane clathrates. When these released their methane into the ocean, it basically poisoned the oceans, and from there things went way wrong.

    Now, when I started studying the climate I was not intrigued by the change in temperature over the last century. To me the oddity is not the ± 0.3°C change in temperature in the 20th century. To me the curiosity is the stability, only a few tenths of a degree in a system running at 290 Kelvin.

    The same is true of the PETM. The real oddity is not the total disruption of the climate system. The critical point is that even with such an extreme disturbance, the pre-impact climate system re-established itself in a geologically short period of time. This is clear evidence of the natural stability of the system.


    • I’m a bit disappointed in your comment, Willis, given your track record of incisive, rational, empirical analysis.

      You seem to be acknowledging a “forcing factor” to an atmospheric trace gas (whether CH4 or CO2), and I just don’t agree that there is any empirical evidence of such a cause-effect relationship

      CO2 has gone up by over 15% in the last 20 years and yet there has been no increase in satellite-observed atmospheric temperature. QED, “CO2 control knob” hypothesis dead

      Methane CH4 cannot possibly have any effect, even on the miniscule scale of CO2, because it is 300 times less existent in the atmosphere. Both CO2 and CH4 radiation-absorption spectra are overlapped by good old natural H2O, so attribution to trace gases is highly suspect

      I know you know all of this, so I’m puzzled by your remark “…….. methane clathrates. When these released their methane into the ocean, it basically poisoned the oceans, and from there things went way wrong”

      “Poisoned”? What does that mean??

      • “Poisoned” might not be the right word… However, there is solid evidence that the Lysocline “shoaled” or became shallower for a brief period of time during the PETM. Several cores obtained from the Walvis Ridge area in the South Atlantic during Ocean Drilling Program (ODP) Leg 208 contained a layer of red clay at the P-E boundary in the middle of an extensive carbonate ooze section (Zachos et al., 2005).

        The PETM was a period of extensive submarine and subaerial volcanic activity (Storey et al., 2007) and pedogenic carbonate reconstructions do support the possibility that seafloor methane hydrates released by that volcanic activity may have sharply increased oceanic CO2 saturation.

        But… The terrigenous paleobotanical evidence does not support elevated atmospheric CO2 levels during the PETM (Royer et al., 2001). The SI data indicate CO2 levels in North America to have been between 300 and 400 ppmv during the PETM.

        So, the PETM may have been an example of ocean acidification (neutralization)… But there is no evidence that it was caused by a sharp increase in atmospheric CO2 levels.

      • I mentioned this below. A marine impact of sufficient magnitude could easily cause all the observed events of the P-E event. For those who remember it, Analog carried a science-fact essay detailing the potential effects of a large planetary strike in 1966. The author, J.E. Enever showed that the results of a marine strike are potentially far worse than a terrestrial strike of similar energy. In partilcualr, the bias of extinctions to marine species, the abrupt increase in global temperature – water vapor is immensely more efficient at transporting energy. A truly large strike could entail cubic miles of water evaporated from a literally boiling crater initially, and a continuous process of warm or hot water output until the crater cooled which could take decades or even centuries. I can’t be sure, but I believe the author actually suggested such and impact as the cause of the K-T event.

      • I didn’t read where they suggested how much the amount of CO2 increased… If the strike causes massive volcanic out pourings (over thousands of years) and the amount of CO2 increase x10 then it could well have a measurable influence to the temperature record, which might not be noticeable within the “noise” if it increases by only 15%. For example, for a x10 increase in CO2 you might get a 2 C degree warming, but at 15% you might only get 0.05 C which is hard to find in the noise.

        There is no doubt in my mind that enough CO2 would have a measurable influence on the temperature, but it doesn’t create a runaway condition… The Earth and its biosphere just sucks up the CO2 over enough time and temperatures are reduced to the “normal” levels of today. That is rather amazing – the stability of the system.

      • Duster
        October 13, 2016 at 3:42 pm

        The K/T boundary impact on the Yucatan Peninsula occurred in shallow water over continental shelf. A combination of its effects caused the mass extinction event 66 million years ago.

        Some geologists and paleontologists still argue for other causes, but the case is really closed for all but those who’ve built careers on alternative or contributory scenarios.

        Even those who argued, based upon observations from western North America, that dinosaurs were declining in diversity before the impact, have recently been shown wrong.

        The Late Maastrichtian (end Cretaceous Period) world was more broken up into different biogeographic regions than previously in the Mesozoic Era, even with the retreat of the North American Interior Seaway. Regional endemism made for lots of diversity. By contrast, during the Triassic and Jurassic Periods, similar genera existed on most continents, of which there was only supercontinent Pangaea in the Triassic.

      • GeologyJim October 13, 2016 at 2:06 pm

        I’m a bit disappointed in your comment, Willis, given your track record of incisive, rational, empirical analysis.

        Life’s funny. When people agree with me, I am seen as providing incisive empirical analysis. But when they disagree, suddenly I’m not smart or incisive any more …

        You seem to be acknowledging a “forcing factor” to an atmospheric trace gas (whether CH4 or CO2), and I just don’t agree that there is any empirical evidence of such a cause-effect relationship

        CO2 has gone up by over 15% in the last 20 years and yet there has been no increase in satellite-observed atmospheric temperature. QED, “CO2 control knob” hypothesis dead

        Sorry for my lack of clarity. There are two separate parts to the CO2 hypothesis, parts which you are treating as one.

        1. Increasing CO2 increases atmospheric absorption of upwelling longwave. This in turn increases downwelling longwave, AKA “increased forcing”.

        2. Increased forcing results in increased surface temperature.

        I agree with the first of these two parts, for which there is ample evidence. I do not agree with the second one, for which (as you point out) there is little evidence. (This current post says nothing about either one of these parts.)

        Instead, I say that the temperature of the planet is not affected by minor changes in forcing, because these are immediately offset by changes in the timing and amount of the emergence of various thermoregulatory phenomena such as dust devils, tropical cumulus, thermally-generated thunderstorms, and the like. See my post Emergent Climate Phenomena for a discussion.

        Regarding clathrates, see David Middleton’s comment above.


      • Chimp, I’m well aware of the K-T discussion. The P-E event took place only about 11 million years after the K-T event. The terrestrial life forms are dominated by groups that survived the K-T event and in general appear to be radiating out of several centers scattered over the global – possibly different regions saw more success for different groups. Placental mammals for instance seem to radiate out of Asia. One thing that does not mark the K-T is a CO2 anomally, suggesting that green plants survived the K-T quite well, but the P-E is a different story, but even so, the CO2 spike is scarcely significant compared to the Permian extinction. The distinct signatures of the potential astronomic bodies suggests that the bodies involved were very different. The K-T is marked by the well discussed iridium anomaly indicating a stony to metallic body strike. The P-E is has only the microtectites reported so far and one speculation is that it was a comet rather than a stony body.

      • There was no spike in temperature at the KPg impact.

        Looks like the PETM spike may be a liverwort outlier.

        In any event the PETM event did not significantly alter an obvious trend.

    • The dislocation of methane clathrates would also explain the shoaling of the lysocline (AKA ocean acidification) during the PETM.

    • “To me the curiosity is the stability, only a few tenths of a degree in a system running at 290 Kelvin.”

      WR: Agree. But the stability we know in the interglacials is exceptional in the Pleistocene. It would be interesting to know why it is more stable now than it is during the glacials. Or, why it is that unstable during the glacials.

      What worries me a bit is is the possibility of a D-O event. We could be at the end of an interglacial. Wikipedia: “The course of a D-O event sees a rapid warming of temperature, followed by a cool period lasting a few hundred years.”

      • Those temperature changes are exaggerated by a factor of 5 for the global impact.

        They have been calibrated by a faulty borehole temperature model. Anyone who has really looked into this data has come to the same conclusion.

      • Bill Illis – October 13, 2016 at 6:34 pm
        “Those temperature changes are exaggerated by a factor of 5 for the global impact.”

        WR: Bill Illis, thanks. In you write: “The problem is that the borehole models appear to be wrong by a factor of 2.”.
        Combining these two numbers, do you suppose that the ‘regional component’ is more than doubling the global temperature change (in the last glacial) for the region around Greenland? Or was the “a factor of 5” a bit a slip of the pen?
        Besides that I would like to know which Antarctic and Greenland temperature graphs you think are presenting realistic surface temperatures for the periods shown. And, not unimportant, do you know reliable deep ocean temperature graphs?

      • Here is Greenland, Antarctica and global temperatures over the last ice age.

        Global temperature change 5.0C, Antarctica 10.0C, Greenland borehole method 25.0C.

        Furthermore, if you take the current scientifically measured formula for how dO18 isotopes vary on Greenland, the temperature change from the ice age should only have been 9.0C (fitting the theory of polar amplification at 2 times).

        But the borehole model for Greenland says that the dO18 isotopes exhibit a different behaviour in the ice ages than they do today. They switched to have 5 times more variability than the global estimated temperature change. 2 times today, 5 times in the ice ages, and not consistent with the verified dO18 isotope formula.

      • Another little Zoom-in to show how this faulty borehole model has led to so many poor scientific results. The last 15,000 years with the Younger and Older Dryas from Greenland borehole models showing crazy temperature changes in a short period of time. (But Antarctica hardly changed at all).

        I note that the Greenland borehole methodology also shows that temperatures on Greenland 14,600 years ago were the same as today. They spiked to +1.5C. (This does coincide with Meltwater Pulse 1A when it appears the back of the ice age glaciers was broken but +1.5C is a little bit of an exaggeration when glaciers still covered half of North America.)

      • There are physical limits to deep ocean temperatures.

        Generally, the deep ocean temperatures are from the densest saltiest water. And the densest water is about -1.0C when it gets a good salt lift from the newly forming sea ice in the Arctic/Antarctic.

        If salty water gets colder than this, it becomes less dense. It starts to form ice crystals and it floats to the very top of the ocean. Because now it is the least dense salty water that there is, sea ice. Basically, if it is colder than -1.0C, it never really gets to be deep ocean water.

        So, the deep, deep ocean water, throughout the history of Earth is from -1.0C in very, very cold ice ages to about 6.0C in the very hottest periods in the Devonian, Permian and Cretaceous. Today, the very very deep oceans is about 1.0C.

        For some reason, climate scientists never took the class where the physics of density of water was provided. It is frankly ridiculous that they put out the fake charts that they do when it is completely impossible.

    • Yes, fascinating but I’m not totally convinced yet. Only when they look at similar marine sediment cores from other periods using the same colour of tray and same methods will I be convinced that the microtektites they found are unique to this short time period. The may well be onto something but lets keep an open mind.

  4. The only certainty from the last 70 years of CO2 atmospheric loading is an increase in vegetation growth and a greening of the planet. No “massive” increase in temperature. Why isn’t this challenged more rigorously? From 1946 to 1978, no warming, primarily global scale cooling. From 1978-1998, warming occurred at a similar rate as early 20th century warming, which occurred prior to CO2 loading. From 1998 to present, there is generally no global trend in temperatures to slightly warming trend, even though the majority of atmospheric CO2 loading has occurred in the last 20 years. So if you have a bolide strike at the PETM to potentially explain part of the event crisis, why also include the as yet proven CO2 loading scenario? We also know that the PETM was preceded by a rapid sea level drop (causing marine life extinctions), that was followed by a rapid sea level rise and transgression (also attributing to marine life extinction).

    • A notable feature of the PETM is actually how few extinctions there were, scarcely above background rate for most groups. There was certainly no mass extinction event, however major among some oceanic species.

      Among large animals, there does seem to have been a reduction in size. And temperature change in the seas led to a redistribution of dinoflagellates, extinction of some coccolithophores and evolution of new species, while benthic forams also suffered extinctions.

      • Correct, few extinctions of terrestrial biota, but marine extinctions of benthic formanifera (~45%) did occur along with some major reorganization of pelagic species, as you point out. This lends credence to sea level changes (rapid drop followed by a rapid transgression and sea level rise) and deep sea anoxia, which has little to do with changes in atmospheric CO2 and more with changes in ocean circulation. As far as terrestrial mammals and a reduction of size, we see the same effect occur generally as one moves towards the equator, and has more to do with temperature regulation than with atmospheric CO2 concentration….

      • Couldn’t agree more. Attributing PETM to CO2 increase confuses cause and effect.

        PETM also shows the earth’s self-regulating ability, as after the spike died down, the planet reverted to the trend it had been on, ie rising temperature from an already high level. Indeed, peak GASTA in the Eocene, as near as can be told, neared the PETM high.

      • A marine impact could have all kinds of serious effects within the marine ecology and chemistry. Also, the heat energy from the impact would tend to be absorbed by water, translated to evaporation and globally distributed where a land strike would radiate away most of the heat quite rapidly. J. E. Enever published a rather detailed discussion of this in Analog in 1966 entitled “Giant Meteor Impact.” He points out many ways in which a marine impact could be immensely worse than a land strike of comparable energy. The only strange aspect of the P-E transition is reduction in C13/C12. Suggestions advanced for that have included destabilization of of massive methane clathrate deposits that abruptly released immense amounts of CO2 ( The wiki article mentions the P-E event and biogenic clathrates.

      • How can this chart be possibly correct?

        Follow the x-axis down to today’s polar deep ocean temperature or the peak of the ice ages and what do you have?

        Deep ocean temperatures of -6.0C or so. Sorry, it has never, ever, ever in the history of Earth went below -1.0C. This is just another faked up climate science chart. Take the calibration method back to 100 Mya and the world’s ocean temperatures are +30.0C. The methodology is completely faked up faulty.

        Redo the numbers so that the peak of the the PETM was about +6.0C (the accepted average global number). Peak dip of the ice ages at about -5.0C (the accepted global average number). Now the chart is accurate.

      • Sorry to stay on this miscalibration problem but I have spent some time on this issue and want people to understand why this very abused chart is so wrong.

        First, it comes from the dO18 isotope database compiled in Zachos 2001. Really, really high resolution ocean cores from all over the world and James Zachos deserves a medal for the amount of work that went into it. This complementing another dO18 isotope database compiled by Jan Veizer going back even farther (3 billion years).

        The temperature estimate from dO18 isotopes comes from an internationally agreed upon Convention called VSMOW. They can be very, very accurate if used properly.

        At various times they have tried to calibrate Zachos 2001 database for the PETM and the Eocene Optimum (at 12C) as variously described it as being Polar Ocean / Ice-Free Ocean / Deep Ocean / Abused by Hansen over and over again. Really just to scare people.

        But if you extend this calibration methodology even farther back in time with the rest of the dO18 isotope database, you get completely ridiculous temperatures of 40C in the distant past and no Carboniferous ice age, no Ordivician ice-age, no Snowball Earth, Cambrian animals boiled alive in extremely hot oceans.

        The people that abuse this chart should know what they are doing. The scientists who worked with the databases in the earlier years understood how to make it accurate but then the exaggerators took over and realized they could scare everyone with the PETM warming event.

        Here is what happens when you extend this temperature calibration used in this chart farther back in time (and my corrected calibration).

  5. As I have stated on this blog before, anytime there is a massive change in the
    earth’s reasonably steady state, IE, variance from the regular cycles, a reasonable
    response would be to search for external input of massive amounts of energy.

    Periods of extreme vulcanism and a massive release of methane hydrates into the
    oceans and atmosphere would be a response to a large imput of mechanical

    The heating of the earth’s crust and the shock and vibration of the strike would
    release a massive amount of natural gas (hydrates) from its zone of stability.

    This would explain the large increase in atmospheric CO2.

  6. Interesting for sure. Do they have any idea if anything else increased as a result of this impact or was it just CO2? Seems like something that big would’ve thrown many systems out of balance for a while. I know finding/hypothesizing big CO2 levels guarantees future funding but I’m just wondering what other things may have happened (besides ejecta and particulates).

    • ristvan does bluster usually work for you? As I said, I will travel to your farm and
      demonstrate my method and findings with you operating the test equipment.

      How about it?

  7. Those materials are created from plasma exchanges between planetary bodies too, accretion theory is utterly flawed and the solar system, I have epic doubts it was stable then

  8. So the key historical interpretation and future policy of the world comes down to the color of the sorting trays. Got it.

  9. This is another “explanation” for why we are causing global warming now. Straw clutching science.

  10. The copper projectile they fired at comet Temple1, there was a discharge from the comet before the projectile impacted as shown by a bright flash

    So imagine two celestial bodies in close proximity. Serious excavation of planetary material

  11. PETM might have been serious underwater volcanic activity, so much ocean floor is undiscovered and unknown.

  12. Really interesting paper. I have been brushing up on PETM, last took a close look in 2014. We know the following.
    CO2 was of photosynthetic origin because d13C depleted. Isotopic carbon fractionation by C3 photosynthesis. ESRL has a nice proof using the anticorrelation between seasonal Atmospheric d13C and CO2 ppm. That auto rules out methane hydrate, most of which is known to be biogenic (methanogens) rather than thermogenic because not d13C depleted.
    The estimated PETM CO2 mass (~2000GT) strongly suggests it had to be fossil fuel sourced rather than terrestrial biomass.
    The known microtectite strewn field in North America stretches from Texas to Georgia to Barbados. And dates to the Chesapeake Bay bolide impact crater ~33mya.
    So if the paper inference is correct, we need a North American impact crater in proximity to major fossil fuel deposits. There are 59 known and one additional possible such craters including Chixalub. And there is one dated to <65mya in Eagle Butte Alberta, measuring over 10 km wide and 0.7 km deep. That is interesting because the Larimide orogeny from ~80mya to ~ 55 mya not only formed the Canadian Rockies, it pushed massive southern western Alberta oil deposits to the Northeast where they today form the Athabascan bitumen sands that lie at or just below the surface, the largest such deposit by far in the world with over a trillion bbl in place. 55mya the deposits would have just formed, but would not yet have been bitumen, rather still crude. The impact might have ignited them at the surface just like the Siberian traps ignited thick Siberian coal deposits at the Permian extinction. PETM is similar but on a significantly smaller scale.
    So, the new paper's inference is plausible.

    • Paper published this year found that the carbon excursion was from seafloor methane rather than CO2from whatever source. What effect this finding, if valid, has on a fossil fuel source for the excursion, I don’t know.

      The Paleocene–Eocene Thermal Maximum (PETM) is a remarkable climatic and environmental event that occurred 56 Ma ago and has importance for understanding possible future climate change. The Paleocene–Eocene transition is marked by a rapid temperature rise contemporaneous with a large negative carbon isotope excursion (CIE). Both the temperature and the isotopic excursion are well-documented by terrestrial and marine proxies. The CIE was the result of a massive release of carbon into the atmosphere. However, the carbon source and quantities of CO2 and CH4 greenhouse gases that contributed to global warming are poorly constrained and highly debated. Here we combine an established oxygen isotope paleothermometer with a newly developed triple oxygen isotope paleo-CO2 barometer. We attempt to quantify the source of greenhouse gases released during the Paleocene–Eocene transition by analyzing bioapatite of terrestrial mammals. Our results are consistent with previous estimates of PETM temperature change and suggest that not only CO2 but also massive release of seabed methane was the driver for CIE and PETM.

    • The carbon could also derive from marine biogenic clathrates. And, since a marine strike is three times as likely as a land impact, …. Lots of clathrates under the sea.

    • One of the other million explanation is my favorite: that the Cayman Trench blew out from collection of pressurized gases. Thanks for the evidence showing the PETM was sourced from fossil fuels.

  13. Coincidence is not causation. Correlation is not causation.

    It is just as likely that such an impact also resulted in changes to:
    -cloud cover
    -atmospheric PM
    -albedo of ice caps via fallout (if they existed at the time)
    -orbit of Earth
    -vegetation cover
    -a gazillion other variables that affect climate

    These folk need to stick to analysing fossils, although the grants are probably jucier if they help the left destroy the economy by demonising CO2.

  14. ristvan, you have made absolute statements about methane hydrates in the past.
    First of all it is natural gas hydrates.They call it methane, so they test only for a
    combustible hydrocarbon and finding one, they call thus identiry it methane.If a
    gas chromotograph were used, the ethane, propane, etc. would be identified.

    There is no absolute way to identify a CO2 molecule’s origin based on C12 or
    C13. It depends upon the availibility of the carbon and the pore space through
    which the gas migrate as it rises from deep within the earth.

    Biomass cannot accumulate on the ocean bottom long enough and in
    concentrarions which would allow methane formation. It eaten before
    that can happen.

    As in the Deep Water Horizon spill, scientists searched for the plume 3 months
    after the well was capped. It was gone. Ocean dwelling methanotrophs bloom
    to the limit of the “food” available, so none reaches the bottom.

    In the past, you have said that there is absolute proof that Dr. Gold was
    wrong.You are wrong.

    I understand from your past comments that you have a dairy farm in Wisconsin.
    I will demonstrate to you that natural gas perks up through the soil, and
    is responsible for its richness, If there is a way for me to send you my
    email address, we can make an appointment.

    • JH, you are just wrong about biogenic versus thermogenic methane hydrate origin. The former is from methanogens and does not fractionate carbon isotopes. The later is from catagensis of kerogens derived from planktonic (mainly) C3 photosynthesis, which does fractionate.
      Dr Gold was wrong. There is no oil abiosynthesis. There is some methane abiosynthesis under unusual circumstances, most prominently the seafloor spreading rift in the Framm Strait. Study up and stop spreading abiogenic oil nonsense. The Swedish tesy was contaminated, the Ukraine ‘Russian’ test was bad geology. All readily available for you to research via Google.

      • My view is that “abiogenic” oil from the crust or upper mantle is actually biogenic, produced by the masses of microbes living deep underground whose presence was not fully appreciated previously, or even yet. I agree that some methane can be and is produced geologically.

        Hydrocarbon-rich comets, moons and planets in the solar system show the ubiquity of methane, ethane, etc.

      • Chimp, abiogenic true for methane. Solar system has plenty. BUTCould not have survived rocky earth hot formation. Basic chemistry. True there is abiogenic methane formation on present earth, facilitated by iron catalysis under unusual tectonic conditions. NOT TRUE that there could be abiotic crude oil. Basic organic chemistry again.

      • ristvan
        October 13, 2016 at 4:39 pm

        Comets and asteroids impacting earth after it cooled delivered lots of hydrocarbons here.

        I suggested biogenic oil that appears abiogenic because it comes from such depth. Geologists hadn’t previously appreciated how many microbes there are deep in the crust. Prior paradigm was petroleum mainly from oceanic microbes, but the possibility exists of crude made from crustal microbes.

      • “NOT TRUE that there could be abiotic crude oil. Basic organic chemistry again.”

        Well, not much most likely. If any. It would have to be recently formed and/or very shallow. It is about as 100% certain as anything is in geology that the interior of the Earth is very hot. Thermal cracking of crude oil into shorter chain hydrocarbons and eventually Methane apparently starts at surprisingly low temperatures — 90-100C and accelerates as the temperature rises.

    • “Biomass cannot accumulate on the ocean bottom long enough and in
      concentrarions which would allow methane formation. It eaten before
      that can happen.”

      In a few words, almost certainly not so. Oil shales such as the Utica, Marcellus, etc are lithified gray to black marine marine muds rich in organic materials. There are fossils, but they are mostly confined to lifeforms that appear to have lived higher up in the water column and to have fallen to the bottom only after death — graptolites, a few trilobites, cephalopods. And the faunas are not very diverse. No fossils of bottom dwelling organisms and no feeding tracks. Presumably similar muds exist today in anoxic zones offshore from major river systems.

  15. When these clowns stop claiming that everything produces CO2 and thus always produce warning, anything they write is worthless. A massive collision as described would create enough ash to create and extended multi-year winter, not warming. CO2 is a radiative gas and does not warm the atmosphere during the day—during the day it absorbs and emits IR constantly, being saturated—and adds and removes small amounts of heat constantly. It is during the night that, with no solar input, radiative gases effectively convert heat energy into IR radiation that is radiated in all directions. The downward IR is rejected as the surface is warmer than the air and the upward IR is lost to space, which has no temperature. The radiative gases, water vapor and CO2, mainly (methane is minuscule on concentration compared to CO2), are the reason the air chills so quickly after sundown and why small breezes pick up during days with scudding clouds, as the air in shadow cools rapidly and creates density and pressure differences that create the breezes.

    When you have nothing in your head but the desire to find roles for warming CO2, that is all you will find, similar to the hammer guy always looking for a nail.

  16. Odd that planetary impact/comet impact with earth authors don’t seem to ever cite Velikosky who wrote about the subject in the 1950’s. Don’t have to agree with him to acknowledge his ideas.

    • Velikovsky’s hare-brained “ideas” had no effect on the discovery of asteroid or comet impacts. He concocted imaginary scenarios without any physical basis, having to do with changes in planetary orbits within recorded history. His anti-physical nonsense was gibberish.

    • No, not interested. I already studied this extensively and have no interest in further engaging with a non-scientific ‘lunatic’ fringe on any side of this great climate/energy debate. Anyone with any Google-fu can probe your false abiotic oil ideas for themselves in 30 minutes given my above comment hints. Even you could.
      Just like I have no interest in engaging Doug Cotton’s Skydragon ideas about gravity caused thermopotential so CO2 is not a GHG. Doubly bad physics. Stupid and embarassing.
      Wrong is wrong. Get over it. Please study up more on basic organic chemistry and d13C isotope fractionation. You would verify something already posted here once in previous comments that completely disproves your nonsense. Have a nice day.

    • So post your data rather than requiring me to reply to your BS crap.. I call your bluff. You have got nothing scientific. Put up, or shut up.

      • ristvan does bluster usually work for you? As I said, I will travel to your farm and
        demonstrate my method and findings with you operating the test equipment.

        How about it?

  17. Question, admitting I have not read all the comments and it might have been answered: can they pin things down enough to determine the time relative occurrences of the impact, the temperature increases, and Co2 ?

  18. This is how the alarmist SMH spun the story:

    “The warming was almost instantaneous. In the blink of an eye, geologically speaking, thousands of gigatons of carbon were released into the atmosphere. The global temperature rose by as many as 8 degrees Celsius. The oceans became more acidic. Sea levels surged upward. Hundreds of species went extinct.

    Sound familiar? … This catastrophic period in Earth’s history is the best analog we have to the climate change that is happening today.”

    Really? An “almost instantaneous” rise of 8ºC as opposed to a dribble of less than 1ºC per century, as we warm out of the coldest spell for the last 12,000 years? The latter during an interglacial embedded in an ice age, and the former during a “hot” non-ice age period? If this is the “best analog” there is, it’s little wonder AGW still sits in the trashcan of scientism.

    • Thanks, Alan.

      About 2/3 of the way down that article is some very plausible criticism, especially considering the speculative nature of the findings:

      Even the most conservative explanations of the PETM describe a phenomenon that happened far faster than almost anything in Earth’s history, so researchers are understandably sceptical of suggestions that it could have started in a day.

      James Zachos, a paleo-oceanographer and PETM specialist at the University of California in Santa Cruz, noted that the abundance of microtektites Schaller and Fung found suggests a relatively small impact. A comet of that size wouldn’t have contained nearly enough carbon to trigger the massive changes that characterised the PETM.

      “These things happen on Earth every million years,” he said – the timing of the impact relative to the thermal maximum is probably just a coincidence.

      They hope you don’t read down that far, I guess.

  19. The paper better show where the tektites were cored from.

    The PETM is most often explained by volcanic activity in the north Atlantic as Europe and Greenland split apart in the continuing unzipping of Pangea. Started 200 Mya but the north Atlantic part did not start up until 58-55 Mya.

    Tektites would be expected to be numerous in the north Atlantic at the 55 Mya timeline next to Iceland as the large volcanoes erupted right at this spot.

    • “Tektites would be expected to be numerous in the north Atlantic at the 55 Mya timeline next to Iceland as the large volcanoes erupted right at this spot.”


      “The difference in water content can be used to distinguish tektites from terrestrial volcanic glasses. When heated to their melting point, terrestrial volcanic glasses will turn into a foamy glass because of their content of water and other volatiles. Unlike terrestrial volcanic glass, a tektite will produce only a few bubbles at most when heated to its melting point, because of its much lower water and other volatiles content”

    • From the paper, the core sites are far enough away so that they are NOT from the volcanic activity from the Iceland area.

      But they are very close to the Chesapeake Bay asteroid impact at 35.5 Mya (five kms asteroid so half the size of the Chicxulub dinosaur killer), so the dating and potential mixing should have been taken into account.

      The paper also says the water content is low indicating asteroid origin.

  20. And whether the K-T (Cretaceous-Tertiary) Impact Event And Global Winter (Sagan, ICE AGE) to kill T-Rex and breathen and sisters on Land And Oceans!

    • The PETM temperature spike was only about 3.0C. This is related to my comments above about the fake charts produced by climate science. It was not 6.0C to 8.0C but only about 3.0C above the 4.0C background temps of the time.

      But the data indicates there really was a sudden spike in temps at 55.8 Mya. There are lots of these in the record however.

      The fake chart idea is what gets everyone on the pro-global warming side so excited. They use fake temperature change data and basically ignore all of the other variability and just focus on the PETM spike and pat themselves on the back for choosing the right side. OMG, temperatures spiked 6.0C (reality is only 3.0C) and there was some type of Carbon excursion at the time so that proves our point !!!

      We also know that some monstrous Rift Valley type eruptions occurred at the same time but they seem to be able to ignore that.

      It is more of a curiosity than anything else. Something a little unusual happened at this point but ice ages ending 28 times in the last 2.6 Mys had even more significant temperature changes so why all the “hype”. And that is the answer. “Hype”.

  21. Intriguing that the PETM is a “thermal maximum” while the peak temperatures in the early Eocene are called “Eocene Optimum”. Same with the “Holocene Optimum”.

    Bad choice of words. “Optimum” is a very positive term; it implies that conditions were somehow more favourable (presumably for life) during the Opimums than before or after. Those labels must have been given by ignorant people who didn’t understand the fundamental precept underlying climate science, namely that “warm is bad; cold is good”

    Someone should alert the Ministry of Truth about this. We don’t want people getting the idea that warm times were good times, do we?

    • You’re right. “Spike” would be a better name than “Maximum”, as the thermal peak came later, during the Eocene. If “Spike” doesn’t sound scientific enough, then maybe “Excursion”. Or the ever popular “Anomaly”.

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