How carbon dioxide melted the world

[Dead_Parrot]

Hopefully this will be an end to one set of claims...

Rising levels of carbon dioxide really did bring about the end of the most recent ice age, say researchers. By compiling a global climate record, a team has shown that regions in which concentrations of greenhouse gases increased after the warming were exceptions to the big picture.

There are many ideas about what caused the end of the last ice age 10,000 years ago, but a lack of data has hindered testing of hypotheses. It has been known that changes in temperature and CO₂ levels were closely correlated during this time, but no one has been able to prove that CO₂ caused the warming.

Ice samples from Antarctica even suggested that temperatures rose a few centuries before CO₂ levels, making it impossible for the gas to have been responsible. This provided ammunition for climate sceptics.

But, by analysing data gathered from 80 locations around the world, Jeremy Shakun, a palaeoclimatologist at Harvard University in Cambridge, Massachusetts, and his colleagues have shown that at the global level, warming followed CO₂ increases. The team used seven different records of past temperature, including ice cores, ancient pollen and the chemical composition of fossilized microscopic life.

More: http://www.nature.com/news/how-carbon-dioxide-melted-the-world-1.10393
Also: http://news.sciencemag.org/sciencenow/2012/04/greenhouse-gas-is-no-weakling.html
Paper (sub): http://www.nature.com/nature/journal/v484/n7392/full/nature10915.html

[izquierdista]

1. "no one has been able to prove..."

But kids have been able to make science fair demonstrations:

How many conservatives are smarter than a fifth-grader??

[Dead_Parrot]

2. But knowing it can happen, and knowing it *did* happen, are two different things.

CO₂ causes warming, and warming releases CO₂ through various feedbacks. Because the two rose almost simultaneously, it's a bit of a chicken-and-egg situation as to which started the other: Given the lack of any other explanation it's been a safe bet that the CO₂ started the cycle, but it's nice to have it confirmed.

[longship]

3. Ding, ding, ding! Experiment validates theory