New York, March 31: The Sahara Desert has expanded by about 10 per cent since 1920 partly due to human-caused climate change, say researchers including one of Indian-origin. The findings of their study suggest that other deserts could be expanding as well. “Our results are specific to the Sahara, but they likely have implications for the world’s other deserts,” said senior author of the study Sumant Nigam, an atmospheric and ocean scientist at University of Maryland in the US. Deserts are defined by low average annual rainfall — usually 100 millimetres of rain per year or less.