Earth’s History Sends Climate Warning – Urgent Action Needed

Foraminifera

Chemical fingerprints of past CO2 levels are preserved in microscopic fossil shells such as this foraminifera. Credit: University of St Andrews

A new study of historical carbon dioxide levels stresses urgent action is needed to avoid prehistoric levels of climate change.

The international team of scientists, led by the University of St Andrews, collected data spanning the last 66 million years to provide new insights into the kinds of climates we can ultimately expect if CO2 levels continue to rise at the current rate. The projected rise would result in prehistoric levels of warmth that have never been experienced by humans.

The study, published in the scientific journal Annual Review of Earth and Planetary Sciences on May 31, 2021, provides the most complete history to date of how CO2 has changed over the last 66 million years, the time since dinosaurs last roamed the planet. The data collected shows more clearly than ever before the link between CO2 and climate.

Working with colleagues from Texas A&M University, the University of Southampton and the Swiss University ETH Zürich, the international team pulled together data collected over the last 15 years using high-tech laboratory techniques.

Samples were taken from cores of mud from the deep-sea floor, where microscopic fossils and ancient molecules accumulate, preserving a story of what CO2 and the climate looked like at the time. By firing these ancient atoms through super sensitive instruments, scientists can detect the chemical fingerprints of past changes in CO2, which can be compared with present day changes. For example, the study explains, through fossil fuel burning and deforestation, how humans have now driven CO2 back to levels not seen since around three million years ago.


The history of atmospheric CO2 levels and global average temperature over the last 60 million years: the CO2 scale shows CO2 in terms of doublings, as this is the key control on climate.

Dr. James Rae, from the University of St Andrews School of Earth and Environmental Sciences, who led the international team explained: “For instance, the last time CO2 was as high as it is today enough ice melted to raise sea level by 20 metres and it was warm enough for beech trees to grow on Antarctica.

“If we allow fossil fuel burning to continue to grow, our grandchildren may experience CO2 levels that haven’t been seen on Earth for around 50 million years, a time when crocodiles roamed the Arctic.”

Dr. Rae added: “CO2 has transformed the face of our planet before, and unless we cut emissions as quickly as possible, it will do it again.”

At COP26 in Glasgow this November, politicians will work on international agreements to lower CO2 emissions to net-zero levels, and prevent CO2 rising further.

Reference: “Atmospheric CO2 over the Past 66 Million Years from Marine Archives” by James W.B. Rae, Yi Ge Zhang, Xiaoqing Liu, Gavin L. Foster, Heather M. Stoll and Ross D.M. Whiteford, 31 May 2021, Annual Review of Earth and Planetary Sciences.
DOI: 10.1146/annurev-earth-082420-063026

17 Comments on "Earth’s History Sends Climate Warning – Urgent Action Needed"

  1. The 10th Man | June 2, 2021 at 7:28 am | Reply

    More scare tactics to pump cash into something that is out of control is not helping. Money will be better spent moving localities to higher ground and update our drainage systems to accommodate more 500 year storms. Alternate food sources for coastal areas. Seriously, all of this the sky is falling crap is getting old. We know it. We get it. Redirect and reaffirm. Scientific method going forward.

  2. Baffled by head in the sand approach | June 2, 2021 at 9:13 am | Reply

    Money is better spent ignoring the problem and not speaking the truth of the science? Your talk about treating the symptom and not the cause is equivalent to giving up. I’m baffled by the statement “scientific method going forward” in this context.

  3. More confusing of cause and effect from those who ought to know better; more scare tactics from vested interests justifying the cost of pet research projects.

    Warmth drives CO2, not the other way around. An earth that is warmer for ANY reason has naturally higher levels of atmospheric CO2 because the solubility of CO2 decreases with temperature, and as the oceans warm, they release dissolved CO2 to the atmosphere. This not a controversial point.

    As the planet has recovered from the Little Ice Age, the oceans have warmed significantly. This has clearly played some role in the recent uptick in atmospheric CO2; exactly how much is in dispute. What is not in dispute is that humans are responsible for only about five percent of the 800-plus billion tons of CO2 that flow into and out of the atmosphere in an average year. Is this significant? Possibly. Is it catastrophic? Almost certainly not.

    Furthermore, recent work by William Happer and William van Wijngaarden strongly suggests that at 400 ppm, the greenhouse capability of CO2 is nearly saturated, and that further increases will have little additional impact.

    Note also that the “extra” 120 ppm of CO2 has theoretically increased the net amount of downwelling radiant energy by less than one half of one percent. This does not define a “crisis” as most of us understand the meaning of the word. And if you beg to differ, I have a historic, well-preserved span that you might be interested in purchasing.

    It’s not the warmth we have to fear; it’s the cold. We are still very much in an ice age, and likely to be for the next several million years. The Holocene Interglacial, which we are exceedingly fortunate to be experiencing, is temporary and winding down fast. The return of the ice, a statistical certainty and overdue, will be the worst thing ever to happen to humanity, and may well drive it to extinction. If you are hankering for something to worry about, this might be a pretty good candidate. If we are very, VERY lucky, the CO2 we are adding to the atmosphere might delay the onset of glaciation for a few precious decades. At most.

  4. Clyde Spencer | June 2, 2021 at 11:22 am | Reply

    The study has established a correlation between past CO2 concentrations and temperatures, which is not a new finding. However, that does not establish causation! The authors assert that CO2 is responsible for the increasing temperatures, without demonstrating proof.

    • This… It’s not that hard to see, science has settled on this trash backed up by peer reviewed papers, so that’s enough for them. It’s time to question the fundamentals, we aren’t making any progress. It’s a matter of time until enough people are aware of the situation and they have to correct their models and stop the propaganda.

  5. Marty Mulligan | June 2, 2021 at 5:27 pm | Reply

    I see few citations from readers/commenters for their lighter claims, and absolutely none for the wilder and broader claims. I would expect more from the readers here.

  6. Dr. Ken Towe | June 3, 2021 at 6:04 am | Reply

    These findings are not new. Similar results using foraminifera and boron were published in 2009 in NATURE…Pearson, Foster and Wade. As both papers clearly show CO2 was more than double what is is now and life on land and in the oceans thrived. The carbonate plankton in the late Eocene were not impacted by the much lower pH…no “acidification”. Instead of throwing out more scare warnings the authors should have emphasized that higher levels of CO2 do not mean climate emergencies or urgent efforts to avoid them. A positive optimistic result.

  7. Dr. Ken Towe | June 3, 2021 at 6:19 am | Reply

    Dr. Rae added: “CO2 has transformed the face of our planet before, and unless we cut emissions as quickly as possible, it will do it again.”

    Cutting carbon fuel emissions ASAP does nothing to lower the CO2 we have already added. What it will do is create more economic havoc as the pandemic travel lockdowns have clearly shown. Fuels for transportation would become scarce, higher in price. Solar and wind do not move vehicles. Because even rapid reductions take time, CO2 could reach 500 ppm if zero emissions were ever actually reached. Not a very well thought out plan by those In Paris.

  8. I wonder why no one has looked at astronomy and physics in this debate. Seems to me that gravity and centrifical force would figure into this. As the earth gets warmer and the ice caps melt wouldn’t the centrifical force of the earth turning and the pull of gravity from the moon force the water towards the equator and cause the earth to pull slightly further out in orbit causing another mini ice age.

  9. Yes this is the NEW WORLD ORDER at its finest. Don’t be fooled people. Look up climate gate and don’t forget these are scare tactics to ultimately put 90% of the earth’s population into the ground. Co2 is NOT a pollutant. Every plant uses co2 just like we use oxygen. We have to have both of them.

  10. The climate models were inaccurate and unable to understand earths delayed and accelerated response to co2.And ordinary people and commentors below just haven’t got a clue.

  11. Here’s an opinion from just an average guy who hasnt made any changes in his life to help out and not sure what changes I could make to help out. It seems to me that most of the scientists agree on the fact that human indulgence has caused an increase in the co-2 emissions in the air which help push global temperatures up. We also can identify what activities, industries, etc are the culprit. Make these activities and industries illegal now. Punishable by hostile takeover. Anyone got better ideas or are my grandkids screwed?

  12. What I don’t understand is the drive to curb emissions, with little talk of how to engage in long term carbon storage. Nature isn’t bad at it.

    We humans seem to be going out of our way to remove natural carbon sinks. What is actually needed is to find uses for plant based products to replace artificial ones. Less synthetic fibers in clothes, continue to advance building techniques with wood or plants over concrete and steel.

    Reducing the amount of Carbon that is available to become CO2 is the more logical way to reduce and control Carbon Dioxide levels.

  13. Jackson Treyber | June 3, 2021 at 9:38 pm | Reply

    So are we gonna start using nuclear energy and keep China from building coal plants or is it still not “urgent” enough

  14. Clark Thomas | June 4, 2021 at 2:32 pm | Reply

    It seems there are no facts anymore, if there ever were?

  15. If you take off your co2 colored glasses. The evidence is quite obvious. The earth warmed about 12 k years ago pearled about 5 k years ago and has been cooling in 1k year cycles ever since. The last cool period started which was the coldest period since the last ice age started in late 1200s and ended in early 1800s when the Thames river stopped freezing over every year, and well before co2 levels rose. This warming trend is about 200yrs and is not as warm as the last one .This is not my opinion but simple FACT we can see in the Viking artifacts found underneath the Norway glacier pass and painted cave drawings in the Sahara when the earth was much warmer and wetter. Eventually facts matter over computer prep panned assumptions. The greatest threat to humanity is the coming ice age not warming, not my opinion, a simple fact that obvious to unbiased eyes

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