Loss of forests in India, China during the 1700s led to a decline in monsoon precipitation
The dramatic expansion of agriculture in India and southeastern China during the 18th century — a sprawl that took place at the expense of forests — triggered a substantial drop in precipitation in those regions, a new study suggests.
Winds that blow northeast from the Indian Ocean into southern Asia each summer bring abundant rain to an area that’s home to more than half the world’s population. But those seasonal winds, known as monsoons, brought about 20 percent less rainfall each year to India and southeastern China in the 1850s than they did in the early 1700s, says Kazuyuki Saito, a climate scientist at the University of Alaska Fairbanks. That decline, he and his colleagues contend online June 1 in the Proceedings of the National Academy of Sciences, is the result of deforestation in the region.
In 1700, forests covered between 40 and 50 percent of India and China. But by 1850 that proportion had shrunk to between 5 and 10 perce