Saturday, May 17, 2008

Some more facts

A followup to the "the oceans absorb a lot of carbon dioxide and are slowing global warming" fact. A study published today in Science about the antarctic ocean shows that it's now basically full enough of CO2 that it can't absorb any more. I wonder how long before this happens in the Northern hemisphere. According to the Globe and Mail, scientists figured that this wouldn't happen until about 2050. They call the southern ocean one of the world's largest carbon sinks, accounting for about 15% of all the areas where we can store carbon worldwide. I recall that one of the places the Bush administration had suggested we could put CO2 captured during carbon sequestration at power plants and refineries was in or under the ocean, so I don't know how this impacts that idea.

To give a scale to the amount of CO2 the oceans absorb: "Since the beginning of the industrial revolution, the world's oceans have absorbed about a quarter of the 500 gigatonnes (500 billion tonnes) of carbon emitted into the atmosphere by humans"

Hm. I'm reading a FAQ by the IPCC, and according to them we're currently at 379 PPM of CO2 in the atmosphere, so my earlier estimate was a bit high. They've got a good estimate of CO2 concentration for the past 650,000 years, and it's ranged from 180 PPM to 300 PPM. It's a 35 page FAQ, so I'll have to read it later.

Also, another question. Apparently warming of the land causes an outgassing of carbon dioxde, which will accelerate global warming. I'll have to get more information on that because the BBC just stated it with no explanation, so I don't know where it comes from. Increased rates of decomposition? Carbon stored in rocks or soils? I'll have to find out.

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