Tropical deforestation threatens global food production

Chris Arsenault, Reuters Yahoo News 18 Dec 14;

ROME (Thomson Reuters Foundation) - Tropical deforestation in the southern hemisphere is accelerating global warming and threatening world food production by distorting rainfall patterns across Europe, China and the U.S. Midwest, a study released on Thursday said.

By 2050, deforestation could lead to a 15 percent drop in rainfall in tropical regions including the South American Amazon, Southeast Asia and Central Africa, the study published in the journal Nature Climate Change said.

Much of the logging taking place is to clear land for agriculture. This can cause a vicious cycle, increasing global warming, lowering food production on farms which in turn leads to growers cutting down more trees for farmland, experts say.

"When you deforest the tropics, those regions will experience significant warming and the biggest drying," Deborah Lawrence, a University of Virginia professor and the study's lead author, told the Thomson Reuters Foundation.

Removing trees and planting crops releases carbon dioxide into the atmosphere, contributing to global warming. At the same time, deforested areas are also less able to retain moisture, immediately altering local weather patterns.

The study said if current deforestation rates persist in South America's Amazon rainforest, the region's soy production could fall by 25 percent by 2050.

Logging in the Democratic Republic of Congo or Thailand could also have consequences in other parts of the world, leading to more rainfall in Britain and Hawaii and less rainfall in southern France and the U.S. Midwest region, the study said.

Globally, levels of deforestation are increasing slowly, Lawrence said.

Brazil has brought rates down in a "wonderful success story", she said, while the situation in Indonesia's tropical forests has worsened.

Complete tropical deforestation could lead to a 0.7 degree rise in world temperatures, on top of the impact from greenhouse gases, doubling global warming since 1850.

"Tropical forests are often talked about as the 'lungs of the earth,' but they're more like the sweat glands," said Lawrence.

"They give off a lot of moisture, which helps keep the planet cool. That crucial function is lost – and even reversed – when forests are destroyed," she added.

(Reporting By Chris Arsenault)