Genghis Khan and the climate

How many "great men" have been made by being born at the right time?

The rise of Genghis Khan and the huge Mongol Empire in the early 13th Century may have been helped by good weather, scientists suggest. American researchers studying the rings of ancient trees in central Mongolia have discovered that his rise coincided with the mildest, wettest weather in more than 1,000 years. Grass grew at a rapid rate, providing fodder for his war horses.

The research shows that the years before Genghis Khan's rule were characterised by severe drought from 1180 to 1190, the study in the Proceedings of the National Academy of Sciences said.But as the empire expanded from from 1211 to 1225, Mongolia saw an unusual spell of regular rainfall and mild temperatures.

"The transition from extreme drought to extreme moisture right then strongly suggests that climate played a role in human events," study co-author and West Virginia University tree-ring scientist Amy Hessl told the AFP news agency."It wasn't the only thing, but it must have created the ideal conditions for a charismatic leader to emerge out of the chaos, develop an army and concentrate power. Where it's arid, unusual moisture creates unusual plant productivity, and that translates into horsepower. Genghis was literally able to ride that wave."

Allied to the good weather, Genghis Khan was able to unite disparate tribes into an efficient military unit that rapidly conquered its neighbours.

Genghis Khan: Good weather 'helped him to conquer' (BBC)