Perilous Times and Climate Change
Running out of time: Much of planet could see extreme drought in 30
years: study
October 20, 2010 - 9:54AM
Large swathes of the planet could experience extreme drought within the
next 30 years unless greenhouse gas emissions are cut, according to a
study released Tuesday.
"We are facing the possibility of widespread drought in the coming
decades, but this has yet to be fully recognized by both the public and
the climate change research community," said National Center for
Atmospheric Research (NCAR) scientist Aiguo Dai, who conducted the
study.
"If the projections in this study come even close to being realized,
the consequences for society worldwide will be enormous," he said.
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Parts of Asia, the United States, and southern Europe, and much of
Africa, Latin America and the Middle East could be hit by severe
drought in the next few decades, with regions bordering the
Mediterranean Sea seeing "almost unprecedented" drought conditions, the
study says.
"Severe drought conditions can profoundly impact agriculture, water
resources, tourism, ecosystems, and basic human welfare," says the
study, published in Wiley Interdisciplinary Reviews: Climate Change.
In the United States, drought causes six to eight billion US dollars in
damages a year on average, and drought-related disasters killed more
than half a million people in Africa in the 1980s, the study says.
While vast areas of the world will become extremely dry for long
periods, higher-latitude regions from northern Europe to Russia,
Canada, Alaska and India could become wetter.
Increased moisture in those regions would not, however, make up for the
drier conditions across much of the rest of the world.
"The increased wetness over the northern, sparsely populated high
latitudes can't match the drying over the more densely populated
temperate and tropical areas," Dai said.
Dai used results from 22 computer models used by the Nobel
Prize-winning Intergovernmental Panel on Climate Change (IPCC), to make
projections about temperature, precipitation, humidity and other
climate factors based on current projections of greenhouse gas
emissions.
Maps of the world that Dai produced using the data show "severe drought
by the 2060s over most of Africa, southern Europe and the Middle East,
most of Americas (except Alaska and northern Canada, Uruguay, and
northeastern Argentina), Australia, and Southeast Asia," the study says.
The maps also show that most of central and northern Eurasia, Alaska
and northern Canada, and India would become wetter over the same period.
The study's predictions are based on current projections of what
greenhouse gas emissions will be this century.
What actually happens in the next few decades will depend on several
factors, including the actual future level of greenhouse gas emissions
and natural climate cycles such as El Nino, which often reduces
precipitation over low-latitude land areas.
The study follows on from earlier research, including by Dai and the
IPCC, that found that global warming will probably alter precipitation
patterns as the subtropics expand.