climate warming

In the 30 plus years since scientists started using satellites to track the area of the Arctic ice cap, the size of the ice pack has gotten smaller and smaller. However, new data from NASA's IceSAT satellite shows that the ice has been melting faster than anyone predicted.

In 2002, using data collected during the three-day grounding of all aircraft in the U.S. after 9/11, scientists discovered that contrails—the wispy white streaks that trail jets—were narrowing the natural day-night temperature cycle in well-trafficked areas. Now a NASA study indicates that warmed-up nights are outpacing cooled-down days. In the U.S., for example, detailed atmospheric modeling suggests that contrails could account for a climate-warming trend—just under 0.3�C per decade—measured between 1975 and 1994. That amount may seem trivial, but