"In the rings of ancient and gnarled trees, a team of scientists has found evidence of a period of consistent warmth and wetness in Mongolia between the years 1211 and 1225 -- the exact time that Genghis Khan first rose to power.
Coincidence? They think not.
This unusual stretch of mild temperatures and unprecedented rain in an area traditionally known for its cold and arid climate would have increased the productivity of grasslands in the Mongolian steppe, the researchers say. The abundant grass would in turn increase the number of grazing animals that could live off it."