GW aggravates drought
- "The study (published in the journal Science) compared drought in the
USA, southern Europe and southwest Asia from 1998 through 2002 with
unprecedented warming of seawater in the western Pacific and Indian
oceans. An existing ''warm pool'' in those oceans grew warmer during
that period. The study attributes that rise to global warming.
The warming, an increase of 2 degrees Fahrenheit, combined with the
drying effects of a La NiÃ±a weather pattern in the eastern Pacific
during the same time, Hoerling said.
The combination shifted tropical rainfall and caused the jet stream
to move north of its usual location, the study said. This meant many
major winter storms missed most of North America. As a result, many
parts of the country grew drier, including much of the West, parts of
the South and the Eastern Seaboard. Some areas received as little as
50% of normal rainfall.
''Absent this warm-pool warming, the likelihood is that the drought
would not have been as severe and prolonged,'' says Hoerling, a
meteorologist in the National Oceanic and Atmospheric
Administration's Climate Diagnostics Center in Boulder, Colo. Kumar
is with NOAA's Climate Prediction Center in Camp Springs, Md.
Drought, which persists in several Western states, could have
occurred without global warming or La NiÃ±a, a climate phenomenon in
which cooler eastern Pacific waters produces drier conditions. But it
would not have been as bad or as persistent, Hoerling says.
The study ''should make a number of people sit up and take note,''
says Kevin Trenberth, the head of climate analysis for the National
Center for Atmospheric Research."