[palmer]

Here's another lie from the report:

The global atmospheric concentration of carbon dioxide (CO2) stood at 379 parts per million in 2005, up from about 280 ppm in 1750, before the industrial revolution, the report said. Concentrations of CO2, and methane, another greenhouse gas, exceed ``by far'' the highest in an Antarctic ice-core record stretching back 650,000 years. Those increases are primarily attributable to fossil fuel use and land-use change, Susan Solomon, who chaired talks this week, said at a Paris news conference.

Here's the main source of data: http://cdiac.ornl.gov/ftp/trends/co2/vostok.icecore.co2

Notice the readings thousands of years apart, how can those be compared to the current 150 year blip today? Obviously a blip like today's would be lost since each measurement represents centuries of average CO2 levels compressed into one measurement.

[pieceofthepuzzle]

The relationships are complex. For example CO2 levels are also affected significantly by the amount of deforestation that occurs in developing countries that haven't put efficient agricultural approaches into practice. "A single mature tree can absorb carbon dioxide at a rate of 48 lbs./year..." Blaming the US, as the world is want to do, is a convenient and oversimplified reflex.

Also, I really like to know from these particular climatologists whether or not they would advocate for reducing CO2 ppm to 1750 levels, if the technology were currently available. Are they confident enough in how well they understand determinants of climate to roll the dice by decreasing CO2 levels? What do the models say about our climate if we reduced CO2 ppm to those pre-industrial levels?

[cogitator]

Notice the readings thousands of years apart, how can those be compared to the current 150 year blip today? Obviously a blip like today's would be lost since each measurement represents centuries of average CO2 levels compressed into one measurement.

It's fine to make that observation, but it's specious unless you can propose a natural mechanism that would drive up CO2 concentrations 80-100 ppm in 100 years. As Sigman and Boyle 2000 show (and there are other studies citable that are still trying to figure out how a full glacial-interglacial transition can cause the 80-100 ppm CO2 change), it's not that easy. You might get a short-term perturbation with something akin to a Younger Dryas entry or exit, but what else?