The water we drinkRoyal Society paints unsettling picture of a world 4 °C warmer
If present warming trends continue, the world could warm by 4 °C by 2060; a new, detailed study by the U.K. Royal Society would make global water shortages acute; most of sub-Saharan Africa will see shorter growing seasons, with average maize production will drop 19 percent and bean production by 47 percent compared with current levels; the extreme weather, sea-level rise, and water shortages will drive many people to migrate
Last year New Scientist reported that U.K. Met Office researchers have shown that the world could warm by 4 °C by 2060, devastating much of the Amazon rainforest and disrupting the monsoon cycle. Now the U.K.’s Royal Society has published detailed study of how the world will look when it is 4 °C warmer.
Water shortages will become more severe, says Fai Fung of the University of Oxford, and colleagues. The extent of the warming depends in large part on our actions. If, by cutting emissions we limit global warming to 2 °C, projections suggest water supplies will dwindle because of demand from the growing population. At 4 °C, however, a warmer, drier climate will become the biggest threat to water availability.
Michael Marshall quotes Philip Thornton of the International Livestock Research Institute in Nairobi, Kenya, and colleagues to say that most of sub-Saharan Africa will see shorter growing seasons. As a result, average maize production will drop 19 percent and bean production by 47 percent compared with current levels.
Extreme weather, sea-level rise, and water shortages will drive many people to migrate, says François Gemenne of the Institute for Sustainable Development and International Relations in Paris, France. The poorest, though, may be unable to move. Gemenne says we should make it easier for people to move country.
—Read more in Mark G. New, Diana M. Liverman, Richard A. Betts, Kevin L. Anderson, and Chris C. West, eds., “Four degrees and beyond: the potential for a global temperature increase of four degrees and its implications,” Philosophical Transactions of the Royal Society (13 January 2011)
