The latest climate change research....

Again, we know so little about climate that it seems we are always making new discoveries...

Although a consensus about man-made global warming has emerged, science is rarely completely settled. Climate researchers, especially climate modelers, are digesting the results of several intriguing new empirical studies. First, a study soon to appear in the Geophysical Research Letters by Stephen Schwartz, a senior atmospheric scientist at the Brookhaven National Laboratory, suggests that a doubling of carbon dioxide in the atmosphere would result in an average global temperature rise of 1.1 degrees Celsius (plus or minus 0.5 degrees Celsius). This is considerably lower than the Intergovernmental Panel on Climate Change's (IPCC) best estimate of 3 degrees Celsius. Of course, proponents of dangerous climate change are challenging Schwartz's results.

Second, in August a team led by Scripps Institute for Oceanography Center for Clouds researcher Veerabhadran Ramanathan reported in the journal Nature that soot may boost global warming by 50 percent, at least on a regional basis. The study suggests that atmospheric heating caused by greenhouse gases and soot together is responsible for the melting of Himalayan glaciers over the past half century. Soot may also explain one-third or more of the Arctic warming primarily attributed to greenhouse gases, according to a study published last June in the Journal of Geophysical Research.

And third, MIT climatologist Richard Lindzen proposed in 2001 that the earth might have what he called an "adaptive infrared iris" operating over the tropical oceans. Lindzen's team suggested that they had preliminary evidence that as GHGs accumulated and boosted the temperature of the tropical oceans that a negative feedback would kick in to lower temperatures. To make a long story short, Lindzen's team believed they had found evidence that as the tropical atmosphere warms up, high-altitude ice clouds that tend to trap heat dissipated and allowed heat to escape into space. At the same time, low level rain clouds that cool temperatures by reflecting sunlight increased. Thus, the earth has a self-regulating thermostat that prevents significant temperature increases due to accumulating GHGs. Other researchers questioned Lindzen's results, arguing that they could find no evidence that tropical clouds behaved the way Lindzen hypothesized.

A study in Geophysical Research Letters published in August by researchers at the University of Alabama at Huntsville and Lawrence Livermore Laboratory using satellite data found evidence that Lindzen might be right. Tropical clouds may act in such a way as to cool down the planet.