Carbon dioxide role in past climate revealed

[On the Road]

Researchers at the British Antarctic Survey (BAS) and the University of California, Santa Cruz have discovered that Earth's last great global warming period, 3 million years ago, may have been caused by levels of CO2 in the atmosphere similar to today's.

---snip

BAS Principal Investigator Dr Alan Haywood said, 'There are two schools of thought about past warm intervals. Many scientists suggest that they were caused by ocean currents (like the Gulf Stream) moving greater amounts of warm water from the tropics to the polar regions. Others speculate that increased levels of CO2 in the atmosphere initiated warming all over the planet. We used the latest supercomputing technology combined with chemical analysis of seabed sediments to make a sophisticated reconstruction of past sea temperatures. If the warming was caused by ocean currents, we would expect to see cooling at the tropics and warming at the poles. Conversely, if CO2 was the cause then we would expect both the tropics and the poles to warm. The sea temperature pattern we found points the finger squarely at CO2 rather than the ocean currents. This is a real breakthrough for those of us investigating past climate – we've made a major contribution to a long standing argument and our findings are critical to understanding how climate may respond to emissions of greenhouse gases in the future'.

Clues to past sea-surface temperature come from tiny marine algae that live near the surface. They produce chemicals called alkenones that record the sea temperature. When the algae die they sink and become part of the seabed. Therefore, a record of past sea temperatures is stored within the sediments. Sea-surface temperatures were also predicted using a climate model running on a sophisticated supercomputer based at Manchester.



http://www.scienceblog.com/cms/node/7517

[YankeyMCC]

1. Do they mention where the C02 came from?

I followed the link and didn't see that mentioned in the article and couldn't find more info on the BAS site. (Which is pretty cool in itself, I've always dreamed of going to Antartica, I can't wait to dig into those diaries ;) )

[On the Road]

2. The Article Didn't Mention It

It's just a report from a local site in Antrarctica doing some basic science.

I'd actually rather have it done this way: First establish the facts, then argue over why and where. Global warming deniers are always trying to derail the fact of global warming with questions on what the sources are and who is responsible.