More than 3000 years ago, the Harappan Civilization was one of the largest and most powerful in the world — and it was brought low by climate change — specifically, monsoons in the area stopped and desert took over. Now the same thing appears to be happening right now with monsoons elsewhere in Asia.
The Harappan destruction was caused by naturally occurring climate change, but the human influenced version could have a very similar effect, according to a paper published in Environmental Research Letters.. The authors argue that the next 200 years could see the traditionally reliable Indian monsoon become infrequent and erratic thanks to climate change.
The model suggests that as the climate warms, the Pacific Walker circulation system that brings areas of high pressure over the Indian Ocean could be shifted to bringing those fronts eastward, over India, suppressing the monsoon rains. This could lead to a 40%-70% reduction in rainfall into the 22nd century.
Vast areas of the world rely on the monsoon systems to provide water for agriculture, and their regularity is a major part of the farming system in Asia. If the monsoons were to be altered so dramatically, it would have untold effects on food production for millions of people.