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Posted at 12:45 PM ET, 03/ 1/2011

Report: Peer into the 'deep past' to divine future warming

By Brian Vastag

To move ahead, sometimes you have to look backwards.

That's the message of a new report from the National Research Council that pushes for more science on the wrenching changes that wracked Earth's climate during our planet's "deep history."

Studying these past periods, when the Earth flipped from an "icehouse" state to a "greenhouse" state, will provide vital clues to how the planet is responding to continued greenhouse gas emissions from the burning of fossil fuels, the report says.

But understanding how Earth's climate changed millions of years ago is not easy. Researchers must drill into rock at many points across the world and then search those cores for variations that hint at prevailing temperatures and atmospheric greenhouse gas concentration.

Isabel P. Montañez, a geologist at the University of California Davis who chaired the report committee, said technological advances in the past decade have rapidly improved the ability to measure past climates.

"We now have really sensitive temperature indicators for the oceans," she said, as well as estimates of how much carbon dioxide and methane - the two main greenhouse gases - circulated in the atmosphere.

Already, scientists studying Earth's deep climate history have unveiled some dramatic warming events, the last of which occurred some 55 million years ago

During this period, called the Paleocene-Eocene thermal maximum (PETM), volcanoes spewed huge plumes of gases into the atmosphere over thousands of years, while deeper releases of magma triggered further releases of carbon dioxide from the ground. This warmed the oceans by five or six degrees Celsius, and the oceans in turn released methane gas, leading to runaway feedback loop of greenhouse gas emissions similar to what Montañez and many other climate scientists worry is happening today - but much more quickly.

A mass extinction of ocean life followed, as well as huge migrations of plants and animals to more favorable climes.

"It had an enormous impact on ocean life, and then on land life," said Montañez. "And it took eighty thousands years to scrub out those greenhouse gases by natural processes."

Understanding this event - and other similar occurrences in the even deeper past - will help scientists understand what to expect Earth's climate to look like beyond the year 2100, the report says.

"The key here is, we're putting the amount of greenhouse gases into the atmosphere over decades that the volcanoes released over the course of centuries," Montañez said. "I can't stress enough that when you look at warmer times in the past, they look like where we're heading now."

Today, atmospheric carbon dioxide concentrations are higher than at any time in the past few million years, the report found. If global emissions continue at their current pace, by 2100 the Earth will have more greenhouse gases in its atmosphere than at any time in the past 35 million years.

The $500,000 report was funded primarily by the National Science Foundation, with $50,000 contributions from the U.S. Geological Survey and Chevron.

Chevron, which touts its record as a "green" company, made some $19 billion in profits in 2010 selling the gas and oil products that, when burned, throw millions of tons of greenhouse gases into the air.

(READ COMPLETE COVERAGE: The Climate Agenda)

By Brian Vastag  | March 1, 2011; 12:45 PM ET
 
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Comments

The PETM (PTEM is a typo) cannot be explained except with a large climate sensitivity to greenhouse gases. Of course, more evidence is always welcome.

Posted by: imback | March 1, 2011 1:51 PM | Report abuse

"Already, scientists studying Earth's deep climate history have unveiled some dramatic warming events, the last of which occurred some 55 million years ago

If global emissions continue at their current pace, by 2100 the Earth will have more greenhouse gases in its atmosphere than at any time in the past 35 million years.

"The key here is, we're putting the amount of greenhouse gases into the atmosphere over decades that the volcanoes released over the course of centuries," Montañez said. "I can't stress enough that when you look at warmer times in the past, they look like where we're heading now.""

----------------------

Let me see if I have this right. The last dramatic warming event took place 55 million years ago. By 2100 the atmospheric greenhouse gases will reach levels equivalent to 35 million years ago. We're putting an amount of these gases into the atmosphere in decades equal to what volcanoes released in centuries.

1 million years is equal to 10,000 centuries.
So, 20 million years (55-35) is 200,000 centuries.
And we're dumping greenhouse gases into the air in decades what volcanoes did in centuries.
In other words it will take 200,000 decades (2 million years) for us to dump enough greenhouse gases into the air before we have a major warming event.

Wow... I am soooooo relieved. All these global warming alarmist have been running around like chicken little screaming that if we don't do something NOW much of the world will be underwater.

I'm glad we have a couple million years to figure something out. Thank you Dr Montañez at UC Davis for setting us straight. :o)

Posted by: Phoenix6m | March 2, 2011 6:27 AM | Report abuse

You have it backwards.
In his 1896 paper Arrhenius found that more GHGs means more warming. HOWEVER his conclusion is not supported by the data in his paper.
What is supported is the conclusion that More photon energy (in the greenhouse effect) results in more warming. Arrhenius' conclusion that more GHGs means more warming is proven wrong by Mother Nature every day. Every night the energy coming in & hence the IR energy going out decreases, and the temperature goes down, IN SPITE OF the amount of CO2 going continuously up.
What really happens is that the amount of energy photons is limited, so when you add more CO2 it just becomes more CO2 that sits there and does NOT cause warming.

Posted by: JDoddsGW | March 2, 2011 6:40 PM | Report abuse

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