Revkin claim: About half of CO2 emitted today "will still be aloft in a century"

Climate Debate: Democracy In Action? - Dot Earth - Climate Change and Sustainability - New York Times Blog

In the first three days of the debate on the bill, according to my rough calculation, about 246 million more tons of carbon dioxide flowed into the atmosphere from human activities worldwide. Something like half of that will still be aloft in a century.

That claim is contradicted here:

First according to the TAR, about 65% of the 730 GT of atmospheric CO2 is removed every year. That gives a mean residence time of 1.52 years, and a half-life of 0.65 years....The IPCC claims that CO2 is an LLGHG, a long-lived greenhouse gas, persisting in the atmosphere variously for decades, centuries, and even millennia, however the residence time by the IPCC formula and data is between 1.5 and perhaps 5 years.

Update: Note also this claim:

Senator Lieberman has estimated the bill would reduce overall U.S. greenhouse gas emissions by up to 63% by 2050. The bill states as its purpose: "Prompt, decisive action is critical, since global warming pollutants can persist in the atmosphere for more than a century."