The Paleocene-Eocene Thermal Maximum (PETM), a rapid warming event 56 million years ago, may have been triggered by changes in Earth’s orbit.
An international team of scientists has suggested that changes in Earth’s orbit that resulted in hotter conditions may have played a role in triggering a rapid global warming event that occurred 56 million years ago. This event, known as the Paleocene-Eocene Thermal Maximum (PETM), is considered to be an analog to modern-day climate change.
“The Paleocene-Eocene Thermal Maximum is the closest thing we have in the geologic record to anything like what we’re experiencing now and may experience in the future with climate change,” said Lee Kump, professor of geosciences at Penn State University. “There has been a lot of interest in better resolving that history, and our work addresses important questions about what triggered the event and the rate of carbon emissions.”
The team of scientists studied core samples from a well-preserved record of the PETM near the Maryland coast using astrochronology, a method of dating sedimentary layers based on orbital patterns that occur over long periods of time, known as Milankovitch cycles.
They found the shape of Earth’s orbit, or eccentricity, and the wobble in its rotation, or precession, favored hotter conditions at the onset of the PETM and that these orbital configurations together may have played a role in triggering the event.
“An orbital trigger may have led to the carbon release that caused several degrees of global warming during the PETM as opposed to what’s a more popular interpretation at the moment that massive volcanism released the carbon and triggered the event,” said Kump, the John Leone Dean in the College of Earth and Mineral Sciences.
A Rapid Onset of Global Warming
The findings, published in the journal Nature Communications, also indicated the onset of the PETM lasted about 6,000 years. Previous estimates have ranged from several years to tens of thousands of years. The timing is important to understand the rate at which carbon was released into the atmosphere, the scientists said.
“This study allows us to refine our carbon cycle models to better understand how the planet reacts to an injection of carbon over these timescales and to narrow down the possibilities for the source of the carbon that drove the PETM,” said Mingsong Li, assistant professor in the School of Earth and Space Sciences at Peking University and a former assistant research professor of geosciences at Penn State who is lead author on the study.
A 6,000-year onset, coupled with estimates that 10,000 gigatons of carbon were injected into the atmosphere as the greenhouse gases carbon dioxide or methane, indicates that about one and a half gigatons of carbon were released per year.
“Those rates are close to an order of magnitude slower than the rate of carbon emissions today, so that is cause for some concern,” Kump said. “We are now emitting carbon at a rate that’s 5 to 10 times higher than our estimates of emissions during this geological event that left an indelible imprint on the planet 56 million years ago.”
The scientists conducted a time series analysis of calcium content and magnetic susceptibility found in the cores, which are proxies for changes in orbital cycles, and used that information to estimate the pacing of the PETM.
Using Orbital Cycles to Decode the Climate Record
Earth’s orbit varies in predictable, calculable ways due to gravitational interactions with the sun and other planets in the solar system. These changes impact how much sunlight reaches Earth and its geographic distribution and therefore influence the climate.
“The reason there’s an expression in the geologic record of these orbital changes is because they affect climate,” Kump said. “And that affects how productive marine and terrestrial organisms are, how much rainfall there is, how much erosion there is on the continents, and therefore how much sediment is carried into the ocean environment.”
The Marlboro Clay: A Window into the Past
Erosion from the paleo Potomac and Susquehanna rivers, which at the onset of the PETM may have rivaled the discharge of the Amazon River, carried sediments to the ocean where they were deposited on the continental shelf. This formation, called the Marlboro Clay, is now inland and offers one of the best-preserved examples of the PETM.
“We can develop histories by coring down through the layers of sediment and extracting specific cycles that are creating this story, just like you could extract each note from a song,” Kump said. “Of course, some of the records are distorted and there are gaps — but we can use the same types of statistical methods that are used in apps that can determine what song you are trying to sing. You can sing a song and if you forget half the words and skip a chorus, it will still be able to determine the song, and we can use that same approach to reconstruct these records.”
Reference: “Astrochronology of the Paleocene-Eocene Thermal Maximum on the Atlantic Coastal Plain” by Mingsong Li, Timothy J. Bralower, Lee R. Kump, Jean M. Self-Trail, James C. Zachos, William D. Rush and Marci M. Robinson, 24 September 2022, Nature Communications.
DOI: 10.1038/s41467-022-33390-x
The study was funded by the National Key R&D Program of China and the Heising-Simons Foundation.
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20 Comments
“An orbital trigger may have led to the carbon release that caused several degrees of global warming during the PETM as opposed to what’s a more popular interpretation at the moment that massive volcanism released the carbon and triggered the event,”
More importantly, the implication is that the “orbital trigger” resulted in warming that must have started before the CO2 increased, meaning that the role of carbon dioxide was less important than the current paradigm suggests.
“Those rates are close to an order of magnitude slower than the rate of carbon emissions today, …”
Perhaps. The absolute spatial and temporal error increases as one goes back in time. That is to say, both the physical parameters, location, and time appear as though they have had a low-pass filter applied, resulting in high rate-of-changes being suppressed.
No, Dorothy, the science is NOT settled.
Nobody mentions in these climate articles that the Earth is still in its 2.58 million ice age named the Quaternary Glaciation, in a warm period that happens about every 100,000 years and lasts about 10,000 years that alternates with a cold glacial period that lasts about 90,000 that the Earth is overdue for since it has been 11,700 years since the last glacial period. The Earth still has around 200,000 glaciers and 11 percent of the Earth is permafrost. https://en.wikipedia.org/wiki/Quaternary_glaciation
There is an article which says cold weather kills 20 times as many people as hot weather and that moderately warm or cool weather kill far more people than extreme weather. Increased strokes and heart attacks from cool weather are the main cause of the deaths.
‘Mortality risk attributable to high and low ambient temperature: a multi-country observational study’
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)62114-0/fulltext
The cold weather also cause about 4.5 million deaths a year mainly through increased strokes and heart attacks, compared with about 0.5 million deaths from hot weather.
Over the last 500 years the total irradiance from the Sun has been at its highest level during the last 50 years. That would also raise the level of CO2 by warming the oceans.
‘Total Solar Irradiance during the Last Five Centuries’ , Valentina Penza lead author, The Astrophysical Journal 937:84, 2022 October 1
There is another paper by the solar physicist, Valentina Zharkova, who discovered how two magnetic dynamos at different depths in the Sun give the 11-years sunspot cycle and another cycle of around 400 years. She says that the Sun is going to be cooling enough to lead to a mini ice age with probable crop failures in the next few years.
‘Modern Grand Solar Minimum will lead to terrestrial cooling’
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7575229/
The Earth is still in a 2.58 million-year ice age named the Quaternary Glaciation, in a warm interglacial period that happens about every 100,000 years and lasts about 10,000 years that alternates with a cold glacial period that lasts about 90,000 years that the Earth is overdue for since it has been 11,700 years since the last glacial period. The Earth still has around 200,000 glaciers and 11 percent of the Earth is permafrost. https://en.wikipedia.org/wiki/Quaternary_glaciation
This article from 2015 says that cold weather kills 20 times as many people as hot weather and that moderately warm or cool weather kills far more people than extreme weather. Increased strokes and heart attacks from cool weather are the main cause of the deaths.
‘Mortality risk attributable to high and low ambient temperature: a multi-country observational study’
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)62114-0/fulltext
This study says that cold weather causes about 4.6 million deaths a year mainly through increased strokes and heart attacks, compared with about 0.5 million deaths from hot weather.
‘Global, regional and national burden of mortality associated with nonoptimal ambient temperatures from 2000 to 2019: a three-stage modelling study’
https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(21)00081-4/fulltext
Over the last 500 years the total irradiance from the Sun has been at its highest level during the last 50 years. That would also raise the level of CO2 by warming the oceans.
‘Total Solar Irradiance during the Last Five Centuries’ , Valentina Penza lead author, The Astrophysical Journal 937:84, 2022 October 1
There is another paper by the solar physicist, Valentina Zharkova, who discovered how two magnetic dynamos at different depths in the Sun give the 11-years sunspot cycle and another cycle of around 400 years. She says that the Sun is going to be cooling enough to lead to a mini ice age with probable crop failures in the next few years.
‘Modern Grand Solar Minimum will lead to terrestrial cooling’
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7575229/
“The Paleocene-Eocene Thermal Maximum is the closest thing we have in the geologic record to anything like what we’re experiencing now and may experience in the future with climate change,”
what utter crock. with a statement like that, you know the ‘science’ is going to be stuffed into whatever political form required. We’ve had many, many, warming events like now, and many more far faster and hotter. we don’t even have to go back 2000 years to see faster warming, and a higher temperature.
we are lucky that it warmed up before the CO2 levels dropped below starvation levels for our food crops. the majority die at < 176 ppm.
And, as the paper showed. Warming drives CO2.
If CO2 warmed us, we would not get record cold nights after record warm days (we do), and if we looked at the rate of cooling after sunset in regions with no wind, then plotted the rate vs temperature and initial CO2, then we wouldn't see that cooling increases with CO2, at all initial temperatures (we do, and this is something any reader can test by looking at the data).
It is so disheartening to live in a time where lies rule the world, and science is prostituted to serve an inimical elite.
Tell me that you don’t understand science without telling me that you don’t understand science… That day/night thing was hilariously stupid, but don’t quit your day job yet.
Since you present yourself as being some kind of an expert on science, with more than a passing acquaintance on meteorology/climatology, how about explaining just why “That day/night thing was hilariously stupid, …”
This is politics dressed up as science. I see no postulates, no theories, just gloom and doom false correlations.
Se Dan Britt’s presentation regarding Milankovitch cycles on YouTube.
Only God Knows the truth.Scientists try to predict what God will do . Before long the scientist kicks the bucket and his predictions and theories are buried soon with him. Only a few concepts have remained stable for more than two generations. As a geologist i welcome a lot of fantacy stories of my mother earth as she is an enigma to all, leave alone her parental family , the solar system.
No wonder that India is a backward, illiterate, tin pot little asian country… After all, they appoint science-denying, cow-dung-licking re****s like this in to government positions.
I am not a scientist or knowledgeable about climate matters, however, I do believe everyone is entitled to their opinion unless it’s like the hateful garbage in your post. WHAT THE
Everyone is entitled to an opinion, and here’s mine. Some opinions are better than others. Putting a god monger IN CHARGE of a science project (Dr.L.S.Suryanatayanan) guarantees millions will be vexed for decades by the nonsense he insists is REAL being inserted into the scientific product he is commissined to create for public use.
There have been tens of thousands of religions, and the only one that’s true is yours. Discuss.
Discussion: Many intelligent people are capable of keeping their religion separate from their secular job. That does, however, not seem to be the case for adherents of the Gaia religion, more commonly known as Global Warming Alarmists.
I think the US could use a goodwill ambassador to India that has a little humility and is not so arrogant that they think it is acceptable to insult others they disagree with. Please don’t apply for the job. You have demonstrated that you are not qualified. You are an embarrassment.
However, I have heard that there is an opening for “The Ugly American of the Year.” You seem more than qualified for that.
Dr. Suryanatayanan, please accept my apology for the juvenile behavior of a fellow American’t. It has been my observation that the essence of immaturity is the inability recognize it.
Milankovitch proposed his cycle theory in the 1930s. None of this is “surprising.” What is surprising is that a climatologist parroted the C02-is-the-control-knob-of-the-climate mantra even while acknowledging that the Eocene warming event was not caused by CO2. But then, “Nature Communications” serves as a megaphone for catastrophist propaganda.
Imagine a house fire that gets started by an electrical spark. The spark falls on gasoline cans stored in the house and sets off a conflagration. The spark started it, but it wouldn’t have been so bad if it wasn’t for the gasoline.
The oceans and permafrost can release a lot of CO2 when the temperature increases. That’s similar to the gasoline stored in the house. Now, imagine while the fire is raging some idiots bring in additional gasoline stored somewhere else (CO2 from fossil fuels) in to the house. Would that make the situation better or worse?
Big Oil will try to seize on this and say “See, it’s orbital changes (Natural)”. But if you read closer, you will see that Orbital changes started the warm up, by causing the release of CO2 amplifying the warm up effect. This can later result in an ice age as a rebound effect. Yeah, climate is complicated.
Exactly. But that won’t stop the paid copy/paste trolls from smearing their excrement all over the comments section… as they already have.
Ralph Gardner, Clyde Spencer, Flow In – multiple accounts by the same PR firm that copy pastes made up drivel. You can see that there is no mention of anything in the article in those pasted posts. They are getting lazy.
“You can see that there is no mention of anything in the article in those pasted posts.”
I think that your emotions are getting the better of you. I quoted statements from the article, and then commented on them.
Your libelous remarks are not only wrong, but they demonstrate you doing what you accuse me of. What kind of person accuses someone of of being duplicitous and being in the employ of a PR firm when they have no evidence to support such a claim?
I make it a point to explain why I think something is wrong, and frequently include links to supporting evidence. What I see you doing is engaging in ad hominem attacks and making false, unverifiable claims. I don’t think that such actions will be very effective in convincing intelligent readers that they should believe you.
There is a lot of confusion on COx2 emission and changes it is bringing to our climate. Geologists interpreting these changes have been predicting a catastrophe causing many types of shortages leading to end of civilisation.