Serious droughts expected in large parts of the world in coming decades

By Stephen Leahy

CANCÚN, Dec 8, 2010 (IPS/TerraViva)

As the world heats up, continents are drying up, with severe droughts forecast in the future. But negotiators at the climate summit here seem to have forgotten about water in their endless discussions over forests, carbon trading and finances.

“The main impact of climate change is on the planet’s water cycle,” said Henk van Schaik of the Cooperative Programme on Water and Climate, a foundation based in the Netherlands.

“Climate-driven changes in the water cycle will affect large regions of the world,” van Schaik told TerraViva at a side event meeting here at COP 16 in Cancún .

The impact of climate on the world’s water resources is not addressed within the U.N. climate framework, said Anders Berntell of the Stockholm International Water Institute.

“Negotiators here see it as just another sector of the economy but it is a basic element for life. Water is the bloodstream of our planet,” Berntell said.

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The global water cycle has already been affected with more intense rainfalls and decline in the evapotranspiration rate over land, according to new scientific research. Evapotranspiration is the term that describes the process of water evaporation and plant transpiration from the Earth’s land surface to its atmosphere.

As the temperature goes up, rates of evaporation are expected to increase. They did until 1998, when there was a leveling off and then a decline in recent years, even though the planet continued to warm, said Beverly Law, a global climate change researcher at Oregon State University.

“Evapotranspiration depends strongly on the amount of water available… the decline seems to be because less water is available,” Law, who led the first global study, told TerraViva.

There is less water because the soils in large areas of the Southern Hemisphere, including major portions of Australia, Africa and South America, have been drying up in the past decade, Law and her colleagues reported in a study in the journal Nature last October.

Not only are soils drying up, since less of the sun’s energy is being used in the evapotranspiration process, more is available to warm the air in these regions, says Law.

Within the next 30 years, large parts of parts of Asia, the United States, and southern Europe, and much of Africa, Latin America and the Middle East could experience serious droughts based on another study also published last October.

“We are facing the possibility of widespread drought in the coming decades, but this has yet to be fully recognised by both the public and the climate change research community,” said Aiguo Dai a scientist at the National Center for Atmospheric Research (NCAR) in the U.S. state of Colorado.

“If the projections in this study come even close to being realised, the consequences for society worldwide will be enormous,” he said in a release. Dai’s projections are based on computer climate modelling of the future as the climate continues to heat up.

Although based on models, those projections are fairly “robust”, says Kevin Trenberth, a senior climate scientist who is also at NCAR. Climate experts have long maintained that one of the major effects of climate change is “that places already wet get wetter and places already dry get drier”, Trenberth said in an email.

Water is not only an essential element for life, it is essential for nearly every sector of the global economy, including energy, manufacturing, transport, agriculture and more, noted Laura Tuck, director of the Sustainable Development Department at the World Bank.

“By 2030 in order to feed the world, water use for agriculture will need to increase 45 percent,” Tuck told attendees at the side event meeting.

Energy demands will be 160 percent higher and some of that will have to come from hydroelectric power. Many proposed climate mitigation plans, like reducing forest degradation and deforestation (REDD), or sequestering carbon in soil cannot be accomplished without water, she noted.

“In addition, institutions need to change because they were built in a world when there was no climate change,” Tuck said.

There has been some progress, with consideration being given to including water on the agenda of the next Subsidiary Body for Scientific and Technological Advice (SBSTA) meeting in June of 2011, reported Berntell of the Stockholm International Water Institute.

“We have to do more to explain the value of water,” he said.

via Climate Changes Herald a Future of Widespread Drought | COP16 CLIMATE CHANGE CANCUN 2010.