Recently, some scientists have studied the impact of climate change on human society in history  They found that more than 80% of the world's countries and regions had twice as many wars in cold climates as in warm periods; in China, wars, widespread unrest and dynasty replacement over the past 1000 years mostly corresponded to particularly long cold periods; there was a close link between Europe's Little Ice Age from 1550 to 1850 and witch hunts in European history and even the French Revolution
Climate warming is an important cause of human conflicts and wars. For example, during the temperature increase from 1981 to 2002, the number of civil wars in sub-Saharan African countries increased than usual
 As a result, they concluded that cooling climate will lead to social conflicts and dynasty replacement