Carbon dioxide levels highest for 650,000 years

Shafts of ancient ice pulled from Antarctica's frozen depths show
that for at least 650,000 years three important heat-trapping
greenhouse gases never reached recent atmospheric levels caused by
human activities, scientists are reporting today.

The measured gases were carbon dioxide, methane and nitrous oxide.
Concentrations have risen over the last several centuries at a pace
far beyond that seen before humans began intensively clearing
forests and burning coal, oil and other fossil fuels.

"CO2 and climate are like two people handcuffed to each other," he
said. "Where one goes, the other must follow. Leadership may change,
or they may march in step, but they are never far from each other.
Our current CO2 levels appear to be far out of balance with climate
when viewed through these results, reinforcing the idea that we have
significant modern warming to go."

New York Times article - 25 Nov 2005