There are many people who agree that the earth has warmed (and haven't had time to fully digest the recent rapid decrease in temperature) but do not agree that an increased concentration of CO2 in the atmosphere is the cause. One problem with the James Hansen-Al Gore hypothesis is that it requires a uniform increase in temperature at both poles. That has not been happening for many years, including the interval after 1979 when the Warmists claimed CO2 caused all of the observed temperature increase. One possible explanation for the reduction in Arctic ice was soot in the atmosphere. Soot increases the absorption of sunlight by snow and ice. There is a lot more soot in the Northern Hemisphere than in the Southern Hemisphere, much of it originating in India and China. Reducing the level of soot is a lot less expensive and destructive to society than reducing the emission of CO2 in energy production. I suppose that is why Al Gore is not focused on soot. This is curious to me since environmentalists should want to clean up the air, and soot is detrimental to humans, animals, and plants while CO2, in the low concentrations projected for hundreds of years from now if all fossil fuels were burned, is not harmful to humans or animals, and is beneficial to plants. Here, from Greenie Watch, is a word about soot in the atmosphere.

SOOT, POLAR BEARS & COST-EFFECTIVENESS

An email from Lee Rodgers [sregdoreel@yahoo.com]

I've been keeping an irregular blog on the climatological effects of tropospheric soot. Contrary to conventional opinion, tropospheric soot has been shown in real field data to cause a net heating effect with up to a 40 percent role in temperature anomalies across the vast Pacific region (alone that'd be 12 percent globally), possibly 35 percent worldwide. Likewise the ice-melting effects of snow-darkening soot in the boreal environment is believed to have caused most of the sesquicentennial thaw in the region, accounting for nearly 20 percent of all global warming in the past two centuries.

Pressing this point have been the parallel efforts of two very conventional climate researchers: Drs. V. Ramanathan and Charlie Zender. Dr. Zender has essentially stated this: That with the albedo-blunting effects of soot being equal to that of extant CO2 warming the benefits of significant soot mitigation in the Arctic would be like cutting CO2 levels by a two thirds (or more). The magnitude of global warming in the Arctic approaches that of 20 percent of all sesquicentennial global warming, and amending the Arctic melt through soot abatement has a far greater impact than mitigating CO2 emissions in an equivalent region elsewhere in the world.

Dr. Ramanathan makes similar points that the the efficacy of soot mitigation is such that societies could broaden the window of opportunity up to 20 years against climate change by simply cleaning up various sources of soot. The higher concentrations of aerosol pollutants in the Northern Hemisphere may be reflected in a notable bias of temperature anomalies north of the equator. Soot mitigation has an immediate effect as opposed to waiting 50 years for the effects of an equivalent reduction of CO2 to finally have an effect.