Dec. 4 (Bloomberg) — Rainfall in parts of Africa may
increase along with rising greenhouse-gas emissions, according
to a report in the journal Science.
Intense rainfall beginning about 14,700 years ago and
ending 5,000 years ago in the Sahara and Sahel regions coincided
with high levels of greenhouse gases in the atmosphere, the
study said. It’s the first time scientists have used climate
models to pinpoint a major cause of what came to be called the
African Humid Period, said Bette Otto-Bliesner, one of the
study’s authors and a scientist at the National Center for
Atmospheric Research in Boulder, Colorado.
“The fact that the model gets it right and that we can
explain it, that gives us confidence that the model can tell us
about future patterns of rainfall in the region,” she said
yesterday in a phone interview. “It was the rise of greenhouse
gases, in particular carbon dioxide and methane, in the
atmosphere that gave that region a common signal.”
Increased rainfall on the continent that will be home to 40
percent of the world’s children by 2050 will present
“critical” challenges to issues including water management,
agriculture and conflict among nations, the study said.
Researchers don’t know how much additional precipitation to
expect. Too much could erode coastlines and waterways or flood
crop lands.
Parts of the continent have begun showing signs of change,
Otto-Bliesner said.
“There are some indications already that vegetation has
increased at the edge of the Sahara desert and the Sahel
region,” she said. “They’ve noticed it on the ground, they’ve
seen it in satellite measurements.”
To contact the reporter on this story:
Justin Doom in New York at
jdoom1@bloomberg.net
To contact the editors responsible for this story:
Reed Landberg at
landberg@bloomberg.net
Randall Hackley, Will Wade