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Politics : The Environmentalist Thread -- Ignore unavailable to you. Want to Upgrade?

To: maceng2 who wrote (12582)	5/16/2007 1:52:03 PM
From: Skywatcher	Read Replies (1) \| Respond to of 36918

Big area of Antarctica melted, satellite finds Tue May 15, 7:11 PM ET Vast areas of snow in Antarctica melted in 2005 when temperatures warmed up for a week in the summer in a process that may accelerate invisible melting deep beneath the surface, NASA said on Tuesday. A new analysis of satellite data showed that an area the size of California melted and then re-froze -- the most significant thawing in 30 years, the U.S. space agency said. Unlike the Arctic, Antarctica has shown little to no warming in the recent past with the exception of the Antarctic Peninsula, where ice sheets have been breaking apart. Son Nghiem of NASA's Jet Propulsion Laboratory in Pasadena, California and Konrad Steffen of the University of Colorado in Boulder measured snowfall accumulation and melt in Antarctica from July 1999 through July 2005. They found evidence of melting in several areas, including high elevations and far inland in January of 2005, when temperatures got as high as 41 degrees F (5 degrees C). "Increases in snowmelt, such as this in 2005, definitely could have an impact on larger scale melting of Antarctica's ice sheets if they were severe or sustained over time," Steffen said in a statement. "Water from melted snow can penetrate into ice sheets through cracks and narrow, tubular glacial shafts called moulins," Steffen added. "If sufficient melt water is available, it may reach the bottom of the ice sheet. This water can lubricate the underside of the ice sheet at the bedrock, causing the ice mass to move toward the ocean faster, increasing sea level."

To: maceng2 who wrote (12582)	5/16/2007 1:52:23 PM
From: Skywatcher	Respond to of 36918

Asian dust plume might sway U.S. climate: scientists By Deborah Zabarenko, Environment CorrespondentTue May 15, 8:11 PM ET Asian desert dust and city pollution is swirling in vast plumes across the Pacific to North America, interacting with storms and possibly spurring climate change, an airborne scientist said on Tuesday. Jeff Stith of the National Center for Atmospheric Research communicated with reporters via Web chat from a research jet flying 40,000 feet above the ocean as part of a mission to track dust and pollution particles blown from Asia to the United States. "We have found enhancements in pollution levels in some of the upper regions of the storm clouds we studied, just yesterday for example," Stith wrote. Stith and his ground-based colleague, V. Ramanathan of the Scripps Institution of Oceanography, aimed to study the interaction between the pollution and dust with high-altitude clouds bearing ice crystals. Ice crystals are found in extremely cold clouds, and when the crystals are composed entirely of frozen water, they reflect lots of sunlight -- that's why these clouds look so white, Ramanathan said by telephone after the Web chat. However, if particles of dust and a dark pollutant known as black carbon managed to get inside the crystals, these clouds might absorb more solar energy rather than reflecting it all, Ramanathan said. The high-flying jet, a specially equipped Gulfstream V, has a range of 6,000 miles and is needed to monitor the dust plumes, which speed across the ocean and occur every few days, the scientists said. FAST-MOVING POLLUTION "We are finding that the entire Pacific Ocean is just a hop, skip and a jump away from North America; the dust and pollution plumes are traveling fast and Hiaper (the scientists' name for the plane) is able to keep up with the plume," Ramanathan wrote in the Web chat. The plane's sophisticated instruments monitor the dust and pollution, but it is also visible to scientists traveling through it, Stith wrote. "The dust itself will be yellowish in color; but when it is mixed with BC (black carbon) it gets brownish; Normally when you are above the dust layer and you look at the sky sideways it will be brown in color," Stith wrote. The plume begins forming when dust is lifted from the Mongolian and Taklamakan deserts, according to Stith. When it passes over East Asia, it picks up aerosol particles from burning fossil fuels, cooking fires and other fires where biomass goes up in flames. The experiment only tracks the plumes as they travel across the Pacific but Ramanathan said high-altitude pollution -- above 1.9 miles -- should be able to travel across North America and out over the Atlantic Ocean. "This is why dust and soot getting into the higher layers is so important," Ramanathan wrote. "This is what makes a local (problem) into a global problem." Images of Asian dust and pollution clouds, the research aircraft and its route across the Pacific can be seen online at ucar.edu.