Earth may be 140 years away from reaching carbon levels not seen in 56 million years

February 20, 2019, American Geophysical Union
A new study shows humans are pumping carbon dioxide into the atmosphere at a rate nine to 10 times higher than the greenhouse gas was emitted during a global warming event 56 million years ago that made the oceans more acidic and drove some marine species extinct. Credit: USGS.

Total human carbon dioxide emissions could match those of Earth's last major greenhouse warming event in fewer than five generations, new research finds.

A new study finds humans are pumping into the atmosphere at a rate nine to 10 times higher than the greenhouse gas was emitted during the Paleocene-Eocene Thermal Maximum (PETM), a global warming event that occurred roughly 56 million years ago.

The results suggest if carbon emissions continue to rise, the total amount of carbon dioxide injected into the atmosphere since humans started burning fossil fuels could equal the amount released during the PETM as soon as 2159.

"You and I won't be here in 2159, but that's only about four generations away," said Philip Gingerich, a paleoclimate researcher at the University of Michigan and author of the new study in the AGU journal Paleoceanography and Paleoclimatology. "When you start to think about your children and your grandchildren, and your great-grandchildren, you're about there."

Scientists often use the PETM as a benchmark against which to compare modern climate change. But the new study shows we're on track to meet this benchmark much sooner than previously thought, as the pace of today's warming far outstrips any climate event that has happened since the extinction of the dinosaurs.

"Given a business-as-usual assumption for the future, the rates of carbon release that are happening today are really unprecedented, even in the context of an event like the PETM," said Gabriel Bowen, a geophysicist at the University of Utah who was not connected to the new study. "We don't have much in the way of geologic examples to draw from in understanding how the world responds to that kind of perturbation."

The exact environmental consequences of PETM-like carbon levels are unclear, but the increased temperatures will likely drive many species to extinction with the lucky ones being able to adapt or migrate, according to Larisa DeSantis, a paleontologist at Vanderbilt University who was not connected to the new study. In addition, it will take thousands of years for the climate system cool down, she said.

"It's not just about 100 years from now; it's going to take significant periods of time for that carbon dioxide to make its way back into the Earth's crust," DeSantis said. "It's not a short-term event. We're really committing ourselves to many thousands of years of a warmer world if we don't take action quickly."

Studying past climate change

The PETM was a global warming event that occurred roughly 56 million years ago. Scientists are unsure what caused it, but during the event massive quantities of carbon dioxide were released into Earth's atmosphere, rapidly spiking global temperatures by 5 to 8 degrees Celsius (9 to 14 degrees Fahrenheit). Average global temperatures during the PETM peaked at about 23 degrees Celsius (73 degrees Fahrenheit), about 7 degrees Celsius (13 degrees Fahrenheit) higher than today's average.

A model for carbon accumulation over time as the sum of carbon emissions, based on the steady increase in emissions and emission rates since 1959. Red circles are annual accumulations through 2015. If the recent trend in emissions continues, we can expect to reach the minimum estimate for PETM-scale carbon accumulation in the year 2159 and the maximum estimate for PETM-scale carbon accumulation in the year 2278. Credit: AGU/Paleoceanography and Paleoclimatology/Gingerich 2019.

Scientists think that during this time and the warm period that followed, the poles were ice-free and the Arctic was home to palm trees and crocodiles. It's not the hottest Earth has ever been, but the PETM was the warmest period since the extinction of the dinosaurs 66 million years ago.

Scientists can't pin down exactly how much carbon was injected into the atmosphere during the PETM or exactly how long the event lasted. But their best estimates say between 3,000 and 7,000 gigatons of carbon accumulated over a period of 3,000 to 20,000 years, based on ocean sediment cores that show changes to carbonate minerals laid down during this time.

The massive carbon release and temperature spike drastically altered Earth's climate, causing a major extinction of organisms in the deep ocean that are a key link in the marine food web. Land animals got smaller and migrated north to cooler climates. Some groups of modern mammals, including primates, appeared for the first time soon after the PETM, but scientists are unsure whether this happened as a direct result of the rapid environmental change.

Comparing past with present

Climate scientists use the PETM as a case study for understanding what environmental changes might happen under current human-caused climate change and when those changes might take effect. But they can only average carbon emissions during the PETM over the whole duration of the event—thousands of years. They don't know what those emissions rates were like on a yearly basis, so it's difficult to compare them to the pace of carbon emissions today.

In the new study, Gingerich found a way to mathematically compare modern to PETM emissions on the same time scale. The results showed current carbon rates are nine to 10 times higher than those during the PETM.

"To me, it really brought home how rapidly and how great the consequences are of the carbon we're producing as a people," Gingerich said.

Projecting current emissions into the future, Gingerich found that if emissions continue to rise, we could be facing another PETM-like event in fewer than five generations. The total carbon accumulated in the atmosphere could hit the lowest estimate of carbon accumulated during the PETM—3,000 gigatons—in the year 2159. It would hit the maximum estimated emissions—7,126 gigatons—in 2278, based on Gingerich's calculations. Humans have emitted roughly 1,500 gigatons of as of 2016.

"The fact that we could reach warming equivalent to the PETM very quickly, within the next few hundred years, is terrifying," DeSantis said.

The findings suggest scientists may not be able to predict the environmental or biological changes that will happen in the coming years based on what happened during the PETM because today's warming is occurring so much faster, according to DeSantis. What makes predictions harder is that today's climate starts from a cooler baseline than the PETM and the species that inhabit Earth are different than those of 56 million years ago.

"It's hard to compare biotic effects because the world during the PETM was quite different," DeSantis said. "We live in a very different world today, with different groups of animals, with humans being the dominant species... but we know there are many negative consequences of dramatic warming on vast numbers of species, including our own."

Explore further: Ancient climate change triggered warming that lasted thousands of years

More information: Philip D. Gingerich, Temporal Scaling of Carbon Emission and Accumulation Rates: Modern Anthropogenic Emissions Compared to Estimates of PETM-Onset Accumulation, Paleoceanography and Paleoclimatology (2019). DOI: 10.1029/2018PA003379

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Mark Thomas
4.8 / 5 (17) Feb 20, 2019
carbon dioxide could equal the PETM as soon as 2159 . . . (when) the poles were ice-free and the Arctic was home to palm trees and crocodiles


Unfortunately, massive political corruption paid for by the oil and coal industries, plus chronic stupidity, mean there is currently no globally-coordinated response, so CO2 levels continue to rise steadily year after year after year.

Perhaps we should erect a monument for any intelligent species that evolves or arrives in the distant future and let them know that we knew about this problem for a long time, but we let our own corruption and stupidity destroy us, and they should beware of the same.
antigoracle
1.2 / 5 (19) Feb 20, 2019
HAWW..HAWW...HEE...Unfortunately, massive political corruption paid for by the oil and coal industries, plus chronic stupidity, mean there is currently no globally-coordinated response, so CO2 levels continue to rise steadily year after year after year.

Perhaps we should erect a monument for any intelligent species that evolves or arrives in the distant future and let them know that we knew about this problem for a long time, but we let our own corruption and stupidity destroy us, and they should beware of the same.

The Mark ThomASS, brays again.
This is the Chicken Shit Jackass, who boasted about his WASTEFUL joyriding in his Tesla, despite the fact that most of its electricity came from fossil fuels.
Yep, chronic stupidity, so erect a monument of this jackass so those intelligent species can know exactly who it was.
In the meantime, keep braying at the heretics and big oil, you jackass, that's how you'll save the world.
marcush
5 / 5 (15) Feb 20, 2019
Agree wholeheartedly Mark. A sad situation for our species and extremely frustrating to the large fraction, if not majority of us who know and would like firm action. The idiocy of characters such as antigoracle would be humorous if it weren't so tragic.
grandpa
1 / 5 (15) Feb 20, 2019
Gosh, I thought peak fossil fuels was years ago.
Da Schneib
4.7 / 5 (14) Feb 20, 2019
56 million years is the time to the PETM. If we hit this, we will die by the billions. But of course most of the people dying will be brown people, so it's no big deal /sarcasm

They have nuclear weapons. What do you suppose they will do? If you and everyone you know and your entire family were going to die, what would you do?

I been talking about cesspool rope gangs. They might kill at most a few tens of thousands of people. That's scary enough, but what Pakistan, India, and China might do is far scarier.
Da Schneib
4.7 / 5 (13) Feb 20, 2019
Never mind Russia, Iran, and North Korea. The nuclear clock has been set forward. Nuclear weapons will be deployed (that's military speak for detonated) over this, and the largest cities in North America and Europe will be devastated.

Doesn't it seem like it's time to start doing something about it? Unless you're stupid.

Those who have the largest population will have the largest remaining population. If you're afraid of brown people, why are you trying to force them to use nuclear weapons to survive? This is stupid.
StupidNet
5 / 5 (14) Feb 20, 2019
Most readers are going to miss the critical point. The RATE far exceed previous warming - and thus, adaption by species will be impossible. Right now, those species that can move are (away from warming areas) but that's not "adaption", that's fleeing. The rate of warming far exceeds adaption capabilities of plants and animals (and humans). It's irrelevant if we "hit the PETM limit in 2159" and factually misleading. We won't be here by then because wet-bulb temperatures would have already far exceeded plant respiration rates - and thus, the global food system of fauna and humans will have already collapsed. Right now, dangerous levels of C02 and methane are leaking out from natural sources - which will continue to accelerate in unstoppable amounts even if humans were to somehow stop their own emissions. This contributes to the rate mentioned in the article. The 2159 limit doesn't matter if we cannot drop this rate of emissions and warming increase down.

(ban antigoracal) please
Thorium Boy
1.3 / 5 (16) Feb 20, 2019
5 million people die each year because of cold. Earth has always had more and more diverse life in warmer periods.
marcush
5 / 5 (13) Feb 20, 2019
Time to get serious about sun shades and the like. Engineering may be our only hope at this point.
kilgoure
1.4 / 5 (18) Feb 21, 2019
How funny!!! So many of you are arguing over this article and the very next 2 articles regarding this issue contradicted this one in terms of our knowledge of how the PETM event started. And so many of you think that we have such control over the planet Earth that we can so severely affect the climate when our dear planet has made far greater changes all on it's own in the past, even funnier yet :) Just once I would like to see a thoughtful and fully researched article on climate change that relies solely on factual information and not hypothesis, assumption, or wishful thinking on the author's part. And for those of you that may think I am just spouting nonsense, just an FYI, when I as a first year high school student I taught my Earth Science teacher a thing or 2 and aced the class because besides fully researching issues, true and factual science is a passion and hobby of mine, unlike the majority of the authors of articles I have seen and read, who are pushing a political cause.
Da Schneib
4.3 / 5 (16) Feb 21, 2019
Oh, neat, another climate troll.
BackBurner
1.6 / 5 (13) Feb 21, 2019
Oh look. another anti-science tramp.
Da Schneib
4 / 5 (12) Feb 21, 2019
No, it's climate trolls who are anti-science.

Go worship your jebus, troll: https://pbs.twimg...pg:large

After that go spit in the oil barrel fire in the middle of the trailer park.

And after they all go to bed you can go fuck your sister like you say jebus told you to.
BackBurner
1.6 / 5 (14) Feb 21, 2019
"Just once I would like to see a thoughtful and fully researched article on climate change that relies solely on factual information and not hypothesis, assumption, or wishful thinking on the author's part."

You may be waiting a very long time if you read this dreck,
BackBurner
1.6 / 5 (13) Feb 21, 2019
No, it's climate trolls who are anti-science.

Go worship your jebus, troll: https://pbs.twimg...pg:large

After that go spit in the oil barrel fire in the middle of the trailer park.

And after they all go to bed you can go fuck your sister like you say jebus told you to.


Schnoz, do you mind if I mention that you have no brain? Or the wit to make an argument?
Da Schneib
4.3 / 5 (12) Feb 21, 2019
You'll surely be waiting a long time if you can't understand the papers, which seems to be your problem.

Typical trailer trash insult detected in the next post. IQ 80 specimens are typically inbred.

Next time don't pose, poser trailer trash troll.
BackBurner
1.6 / 5 (13) Feb 21, 2019
Dude, I wrote those papers. Read them and weep. Wastrel. Cheap assed fruit fly. Direct path to ground. Useless as tits on a boar hog.
Da Schneib
4.3 / 5 (12) Feb 21, 2019
Who wrote what papers?

You ain't linked any papers. Like most poser trailer trash trolls, you lie. And more transparently than most.
Da Schneib
4.1 / 5 (13) Feb 21, 2019
Still waiting for your "papers" poser liar trailer trash troll.
BackBurner
1.6 / 5 (14) Feb 21, 2019
:) Sure. You first. Scum. Schnoz, Big boy? Big nose? Proud of that?

You pathetic waste of oxygen.
Da Schneib
4.1 / 5 (13) Feb 21, 2019
Where's these "papers" you claim to have written?

Still waiting, poser liar inbred trailer trash troll.
HeloMenelo
4.7 / 5 (12) Feb 21, 2019

The Mark ThomASS, brays again.
This is the Chicken Shit Jackass, who boasted about his WASTEFUL joyriding in his Tesla, despite the fact that most of its electricity came from fossil fuels.
Yep, chronic stupidity, so erect a monument of this jackass so those intelligent species can know exactly who it was.
In the meantime, keep braying at the heretics and big oil, you jackass, that's how you'll save the world.


Dumber i have never seen, going electric is the Right choice no matter what the initial source dumbnuts, what matter is that in future the source for E -Cars will become squeaky clean ! braying at big oil ? Well what did you expect, they are Destroying the earth, yet you..yes You will cut your balls off clean for their cause, o wait... you already have ! Next time try not fart but rather speak, maybe it will appeal to those brighter than you, then again, maybe not.
HeloMenelo
4.6 / 5 (11) Feb 21, 2019
Gosh, I thought peak fossil fuels was years ago.

Gosh you so deep up the black Oil's filthy arse, your vision got impaired. but wait so did your memory...!
What matters is the devastation relentlessly caused by Big Oil and No single one of you LOSERS is doing or will be doing ANYTHING ABOUT IT !

That you are so delusional, self centered, arrogant and short sighted not to mention uneducated and absolutely careless about something as serious as this is beyond understanding !
HeloMenelo
4.4 / 5 (13) Feb 21, 2019
:) Sure. You first. Scum. Schnoz, Big boy? Big nose? Proud of that?

You pathetic waste of oxygen.

C'mon LOSER We are still waiting, O wait... you lost your brain instead ! Knew it.
HeloMenelo
4.4 / 5 (13) Feb 21, 2019
5 million people die each year because of cold. Earth has always had more and more diverse life in warmer periods.

Were you born Stupid or are you just naturally dumb ?
kilgoure
2.3 / 5 (3) Feb 21, 2019
Oh, neat, another climate troll.
, Dear Da Schneib, it is too bad you are unable to read what I actually said, had you done so you would realize that I am actually quite the opposite...darn fool ijit
kilgoure
2.3 / 5 (3) Feb 21, 2019
"Just once I would like to see a thoughtful and fully researched article on climate change that relies solely on factual information and not hypothesis, assumption, or wishful thinking on the author's part."

You may be waiting a very long time if you read this dreck,
, Dear Back Burner, DUH!!! I know and expect to actually never see it occur. My only goal was to get intelligent people thinking. Thankfully I caught your attention, unfortunately I caught others as well and I appreciate your comments.

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