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Ancient Warming Has Disturbing Implications for Our Future

Seafloor sediments from Spitzbergen, on the edge of the Arctic Ocean, tell a tale of ancient warming. Credit: Michael Lemonick.

People who want to cast doubt on the idea that humans can change the climate sometimes point to the distant past. Climate change was happening long before anyone invented cars or coal-burning power plants, they argue, so the current episode of climate change must be natural as well. It’s kind of like arguing that since wildfires existed for millions of years before matches were invented, they can’t be started by people.

Climate scientists think of ancient climate change in a very different way. They see it as something that might help us understand what might be in store for us in the future. One period that especially interests them is something called the Paleocene-Eocene Thermal Maximum (PETM), a time about 60 million years ago, when levels of carbon dioxide (CO2) — the primary greenhouse gas — shot up relatively fast, stayed high for about 170,000 years, and then dropped again. Global temperatures rose by about 9°F on average — at the upper end of what’s projected for the coming century.

There’s plenty that scientists don’t understand about the PETM, including what, precisely caused it. It may have been triggered initially by orbital changes in the Earth’s path around the Sun, much as the warm periods during ice ages have been over the past couple of million years. It certainly involved huge releases of carbon, but it’s not certain whether this came from the massive burning of biomass or coal (naturally ignited, of course), or by the release of undersea methane which oxidized into CO2, or both.

But researchers are learning more all the time, as a new paper in the journal Nature Geoscience makes clear. By delving into an unusually rich and well-preserved set of ancient marine sediments from Spitzbergen Island on the edge of the Arctic Ocean, an international team of researchers has come up with an estimate of how quickly carbon entered the atmosphere at the start of the PETM.

It’s a key question because climate change is really only a major problem if it happens relatively quickly. If it plays out over many centuries, ecosystems will have time to adapt, and the vast infrastructure that underlies the developed world — cities, transportation systems, industrial facilities and more—can be moved, rebuilt, or modified at a reasonable pace and cost. If, as is currently the case, climate change unfolds rapidly, the changes can be enormously destructive.

Based on their analysis of carbon levels in ancient sea creatures dredged from those ancient sediments, the news is not good.

“Our major conclusion,” says lead author Ying Cui, a graduate student in geosciences at Penn State, “is that we’re pumping CO2 into the atmosphere at about ten times the average rate during the PETM.”

There weren’t any cities or highways to destroy back then, but many species of sea-dwelling organisms went extinct. Other species, including many mammals, did better during the PETM than they had before — but that would have forced ecosystem readjustments as well.

That’s at a time when carbon levels were climbing a tenth as fast as they are today, which suggests that the biological world, at least, is poised to go through a far more wrenching set of changes (and just to compound the situation, there weren’t any icecaps before the PETM, so that period of warming didn’t raise sea levels as much as they’re likely to go up during our own episode of climate change).

If these numbers are confirmed by future studies, at least one mystery of the Paleocene-Eocene Thermal Maximum will have been solved — and not in a way that inspires comfort.


By Bob (80501)
on June 9th, 2011

“or by the release of undersea methane which oxidized into carbon, or both.”

“carbon” should be “carbon dioxide.”

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By C. Jeff Dyrek (Illinois)
on June 9th, 2011

Taking a look at our planet we see that almost every inch of every country, especially the U.S. has been cut, bulldozed, plowed and poisoned by humans.  The animals didn’t do it, we did it.  Anywhere you go on the planet, the one species of animal that is everywhere are humans.  Even standing on the North Pole, one of the worlds most inaccessible places on earth, there is a yearly tourist base which depends on carbon fuel to build and maintain. 

The interesting part of this whole story is that there are so many, very educated people, who still say that this is a natural cycle and that we shouldn’t worry about it.  When are we going to wake up, only when it’s too late.

C. Jeff Dyrek, Polar Explorer, Webmaster

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By Mimi K
on June 9th, 2011

Grim news, indeed.  However, the assumption that human beings cannot adapt very rapidly, or that rapid adaptation to climate change is more difficult and costly than gradual, incremental change, is not justified by recent human history.

Joe Romm at Climate Progress implores climate scientists to use the WW2 metaphor when writing about climate change.  If this author followed Romm’s message rules, then rather than writing that rapid adaptation is more difficult and the issue, he would have made a more optimistic, and historically referenced, statement that industrial societies have responded en masse, in global unity, and very rapidly, in a matter of less than one handful of years, despite being woefully unprepared, to a threat to human life.  The changes were in the very fabric of every aspect of modern life, from growing our own food in victory gardens, to a complete shift in manufacturing systems, with changes in gender roles, communities, and world leadership acting as one all happening astonishingly fast.

The critical importance of the WW2 metaphor is that it is our only precedent still part of Western people’s memories and lived stories about a rapid global response and systemic change.  Our own recent history contradicts that a rapid global response is difficult.

But it does take FOCUS. I would argue that the reason we have not yet ‘woken up’ to our global environmental tragedy we ARE all in together is because we lack the single focus that we had in WW2.  We are daily distracted by all sorts of news in the media that serves to make us unable to come together in the one big news story we are all in together—the news about the biosphere.

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By Peter Mizla (Vernon, CT 06066)
on June 10th, 2011

Considering this ancient warming moved over a period of 20,000 years- and the current C02 induction could happen in less then 150 years- I am totally perplexed that the media says nothing about the dire danger we are in. Paid off? Very likely.

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By Malcolm Newell (Chichester, U.K)
on June 10th, 2011

The PETM warming occurred in a world that was largely without Ice, the good news (for us) is that the present Anthropogenic warming is occurring in a world in which there is a huge amount of ice which can already be seen to be moderating the speed at which global average temperatures can rise. In effect, atmospheric and surface temperatures ate restrained from rising due to the cooling effect of the polar and mountain glacial ice.  Although the equatorial temperatures are free to rise, they are restrained as energy is transfered ,by climate and ocean currents, to the Poles.
The slowly rising atmospheric temperatures can be witnessed as mountain glaciers shrink but much of the energy being transfered to the poles is simply being absorbed by the ice as it is transformed (at constant temperature) - into liquid water-remember latent heat of ice?  i.e. energy absorbed but no rise in local temperature-until ALL the ice is melted.

The bad news is that sea levels ARE going to rise, ever more quickly and the energy transfer to the cold polar regions ( especially the Antarctic) Is going to become more violent-i.e. stronger climatic movements (storms!).

Once the ice has gone-look out.

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By Chilli Weather (Oregon City, OR)
on June 13th, 2011

Yes,  the news is unfortunate, but the reality is that humans on earth are quite nearly doomed.  It’s just really hard for a species to make it past the “materials boundary” - the point where it gains the ability to create intentional effects on a global scale - and not destroy itself in less than a millennium.

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By steve bridge australia (3089)
on June 17th, 2011

Perhaps someone could come to Australia and convince the main opposition party - the liberal/national coalition that climate change is real. They are currently holding our nation to ransom with their denial and fear mongering. Their leader Tony Abbott is more concerned with gaining power than he is for the welfare of Australians and the people of the world. He has been on a daily fear campaign for 10 months now and many Autralians are confused and persuaded by his angry rhetoric. Other prominent climate change deniers in his party include Barnaby Joyce and Nick Minchin. They simply don’t believe climate change is real.
We really need help in this country.

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By Dave D. Andconfused (Redding, ca)
on June 20th, 2011

Please illuminate information on evidence of former forests in Antartica.

Will there not be a large bloom of plants absorbing carbon dioxide as things continue?

What was the timeframe for that ancient forest?  Why is every comment posted here a gloom and doom prediction? 

In response to the “polar explorer”.  There is a great deal of land undeveloped still.  You may need to get out somewhere besides urban and polar environments.

Is it possible that our sequestration of animal feces from the natural waterways has diminished the ocean’s ability to grow vegetable matter and absorb CO2?  Why aren’t people growing seaweed in great forests.  Why did the great kelp forests disappear 20 years ago off California.  I would guess that the same kind of aestheta-Nazi’s that try to regulate curb appeal, have hastened and welcomed coastal kelp forests demise with their former occasional super stink that could be smelled for miles around.

How easy would it be to regrow acres of ocean vegetation? 
obtaining rights?  planting? watering?  ensuring kelp forest haters and users don’t hasten their demise.

And if it is proven that certain bacteria can lessen the presence of formaldehyde in concert with plants, why do we not establish a sargasso sea type of seaweed in the pacific “garbage patch” to remediate toxics and co2 together.. 

I wonder if the earth sings the song….“All you do to me is talk talk talk talk.”

Blessings to all and let’s pickup something other than a pen for this one.

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