Sometimes civilizations die due to climate change. Sometimes civilizations arise due to climate change. According to research by Geologist Anil Gupta of IIT Kharagpur declining monsoons could have caused the decline of the Indus Valley Civilization and now it turns out that the Tang dynasty of China and the Mayans were also bought down by shifts in monsoon cycle.
The records show that around the time that these civilizations went into decline, they experienced stronger than average winds in the winter and weaker summer monsoon rains. These weak rains would have reduced crop yields.
The Mayan civilisation and Tang dynasty were contemporary and there is a striking similarity between the Chinese and Latin American climate data. These include a general shift towards a drier climate around AD 750 and three very dry periods between then and AD 910, the last of which coincides with both the Maya and the Tang collapse. [Collapse of civilisations linked to monsoon changes]