New Study Shows Three Abrupt Pulses of CO2 During Last Deglaciation

vinces99 writes A new study shows that the increase of atmospheric carbon dioxide that contributed to the end of the last ice age more than 10,000 years ago did not occur gradually but rather was characterized by three abrupt pulses. Scientists are not sure what caused these abrupt increases, during which carbon dioxide levels rose about 10 to 15 parts per million – or about 5 percent per episode – during a span of one to two centuries. It likely was a combination of factors, they say, including ocean circulation, changing wind patterns and terrestrial processes. The finding, published Oct. 30 in the journal Nature, casts new light on the mechanisms that take the Earth in and out of ice ages.

"We used to think that naturally occurring changes in carbon dioxide took place relatively slowly over the 10,000 years it took to move out of the last ice age," said lead author Shaun Marcott, who did the work as a postdoctoral researcher at Oregon State University and is now at the University of Wisconsin-Madison. "This abrupt, centennial-scale variability of CO2 appears to be a fundamental part of the global carbon cycle."

Previous research has hinted at the possibility that spikes in atmospheric carbon dioxide may have accelerated the last deglaciation, but that hypothesis had not been resolved, the researchers say. The key to the new finding is the analysis of an ice core from the West Antarctic that provided the scientists with an unprecedented glimpse into the past."

Comments

Abrupt, but like 100 years abrupt?

[Anonymous Coward]

"However, the researchers say that no obvious ocean mechanism is known that would trigger rises of 10 to 15 ppm over a timespan as short as one to two centuries."

We're way, way, way beyond 10 to 15 in 200 years.

Re:Abrupt, but like 100 years abrupt?

[saloomy]

Sounds like they really just don't know.
It likely was a combination of factors, they say, including ocean circulation, changing wind patterns and terrestrial processes.

But at least they are studying and learning.
"This abrupt, centennial-scale variability of CO2 appears to be a fundamental part of the global carbon cycle. "Previous research has hinted at the possibility that spikes in atmospheric carbon dioxide may have accelerated the last deglaciation, but that hypothesis had not been resolved, the researchers say.

The earth has been from +14 to -6 degrees on average from where it is today. Historically speaking, were in the "colder than usual" range of the bell curve today, and thats with using ice cores to detect CO2 levels and temperature histories. Its not like we had a thermocouple hooked up to a server recording that data for millions of years. These deductions are best effort conclusions on data that only tells a very broad stroke of the story.
What upsets me is how demonizing the argument about Global Warming / Climate Change is. The earth will change its temperature. That will happen with or without us, just look at the historical record. Earths temperature isn't stable. And for all those who argue we are burning too much fossil fuels, those carbon atoms weren't created into existence in the ground as they were today, unless you believe the earth is 6000 years old!
They were a part of the global carbon cycle, and buried during mass extinction events and processes that sequestered them to where they are today. It isn't science to say "for sure this and for sure that". Its science to say: "To the level of our current understanding...". Thats it. You can't know for certain, just like they didn't know for certain that the earth was the center of the universe, even though it was proselytized. Its not OK to attack the character of an individual when they are skeptical of your conclusions. All of science works better when there are those who are skeptical. It refines your proof if you are right, or betters your understanding if you are wrong.

As for the problems associated with climate change, it will happen. For those of us living where it will flood, there will be a new continent to live on, once it unfreezes (again!).

Correlation does not imply causation

[laing]

How do we know the CO2 spikes caused the warming? Perhaps the CO2 resulted from increased biological activity occuring as a result of the warming.

This sort of confusion happens a lot in science.

Re:Correlation does not imply causation

[DiamondGeezer]

It happens a lot in science. Have you actually read "The Structure of Scientific Revolutions"? Clearly not.

Correlation does not imply causation

[Anonymous Coward]

" Perhaps the CO2 resulted from increased biological activity occuring as a result of the warming"

A simpler explanation is Henry's law: http://en.wikipedia.org/wiki/Henry's_law

"carbon dioxide from a carbonated drink escapes much faster when the drink is not cooled "

Likewise, carbon dioxide from a carbonated ocean escapes when the ocean warms.

Re:Maybe something like a permafrost melting?

[PopeRatzo]

Don't we have several mammoth cO2 reserves around the planet, right on the verge of finally letting go?

Don't bring my mother-in-law into this.

Causation, CO2 and Warming

[Robear]

[quote]How do we know the CO2 spikes caused the warming? Perhaps the CO2 resulted from increased biological activity occuring as a result of the warming. [/quote]

CO2 is a warming gas in the atmosphere; in the absence of any other changes, adding CO2 will warm the atmosphere. However, as the article notes, we don't know what caused the quick ramp-up of CO2, and we *do* know that other factors (both cooling and warming) were in play. We also know that over time the atmosphere warmed enough to end the ice age in question.

What is safe to say is that CO2 has a warming effect, which could be counterbalanced *and* added to by other factors. It's the overall balance of these things that tilts the scales one way or another. CO2 is just one piece.

But it's not mistaking correlation for causation to note that adding CO2 to the atmosphere will result in increased warming. That's just basic physics. The fact that it could be offset by something else is immaterial to your point.