NASA links jet contrails to global warming. Now what?
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