Young boys working in a newly cropped field in Africa. PHOTO COURTESY USGS.
Forecast calls for below average rains this spring and early summer
Spring rains in the eastern Horn of Africa are projected to begin
late this year and yield less moisture than average, according to a
study led by the U.S. Geological Survey.
Long-term climate research shows that droughts around the Horn are
linked with global warming, as the Indian and west-central Pacific have
warmed faster than other areas, resulting more rain over the oceans,
with drier air descending over east Africa.
“Rainfall projections were estimated by looking very closely at all
the prior droughts from March–May since 1979 in the eastern Horn of
Africa,” said USGS scientist Chris Funk, who led the research. “We found
that sea surface temperatures in the western/central Pacific and the
Indian oceans are key drivers of rainfall during that time period. So we
compared sea surface temperatures from past years to March 2012, and
developed an updated rainfall forecast for this spring season.”
Based on data from previous drought, the study concludes that, from
March to May, the rains are expected to total only 60 to 85 percentage
of the average rainfall in this region.
This is a significant
deterioration compared to earlier forecasts.
Lower rain amounts would have significant impacts on crop production,
rangeland regeneration for livestock, and replenishment of water
resources.
This would put greater stress on the region, particularly Somalia which is still recovering from a famine declared last year,
as well as Kenya and Ethiopia which also experienced a severe food
crisis. An increase in food insecurity and in the size of the food
insecure population is likely.
“The concerning picture that emerged from FEWS NET climate monitoring
services was that despite the good rains of the past winter, the
situation east Africa has deteriorated very rapidly, to a point that the
water deficits and vegetation health looked as bad as this time last
year,” said Funk.
Based on the latest forecast, the U.S. State Department released a statement announcing its intent to provide additional funding to aid refuges and drought-affected communities.
Famine Early Warning Systems Network
The rainfall projections were completed by the Famine Early Warning Systems Network,
which helps target more than $1.5 billion of assistance to more than 40
countries each year. The network monitors high risk areas of the
developing world with the most food insecurity, identifying critical
situations in which food aid will be needed.
As the globe has warmed over the last century, the
Indian and central/western Pacific oceans have warmed particularly fast.
USGS scientists found that the warming of these oceans affects rainfall
over large areas of the Horn of Africa.
The resulting warmer air and increased humidity over the Indian and
Pacific oceans produce more frequent rainfall over the oceans. The air
then rises over the equatorial Indian and Pacific oceans, and flows
westward, descending over Africa. Since the air has already lost
moisture from rainfall over the oceans, this leads to decreased rain
amounts in parts of eastern Africa. Trends toward increased frequency of
drought that we are seeing now appear likely to continue into the
future as warming continues.
“Essentially, our research has progressed to the point where we can
recognize fairly well the climate patterns linked to the recent
droughts, and we hope this helps identify potential bad seasons in
advance to raise awareness,” said Funk.
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