Alaskan residents who watched as wildfires claimed a record 10,000 square miles 26,00 square kilometers of land in 2004 can take cold comfort in the fact that the choking smoke endured during wildfire season could blunt some of the effects of global warming. Researchers from the National Oceanic & Atmospheric Administration NOAA analyzed the short-term climatic impact of smoke from wildfires that swept Alaska and western Canada in 2004, burning 22,000 square miles 57,000 square kilometers in total. They report in the Journal of Geophysical Research that the billowing clouds may have a cooling effect on the Arctic, where dwindling ice sheets have researchers worried about the potential for sudden climate changes to come. They say that smoke carried north on the wind absorbs some of the sun's rays and perhaps lessens the impact of global warming for weeks or months at a time, to a degree that depends on the soot's thickness, the sun's elevation and the brightness of the surface ground or water. They note signs that the 2004 wildfires had atmospheric effects as far north as Greenland and the islands above Norway and down south to the Gulf of Mexico. The only hitch: Particles that land on snow or ice might actually cause it to melt faster. Still, NOAA says, it's possible the Arctic might benefit if the wildfires intensified--a distinct possibility as global warming leads to drier summers up north.  More