Reuters: Climate change could cost the African continent more farmland than the United States uses to plant its eight major field crops combined, according to a study published in the June issue of Environmental Science and Policy. Farming on up to 1 million square kilometers (247 million acres) of land in Africa could subside by 2050 as climate change makes areas too hot and dry for growing crops, the study said. The latest U.S. Agriculture Department data puts plantings of the eight …