According to PNAS and the NSF and the Daily Mail, Genghis Khan conquered Asia because an ideal combination of warmth and rainfall caused grass production to rise..
All this conjecture about perfect weather leading to huge crops resulting in Genghis Khan conquering of Asia comes from the tree rings of only 17 trees.
“Between 1211 and 1225 – the exact time of the Mongols’ rise – central Mongolia saw one of its wettest, and warmest, periods for 1,000 years“
“We propose that these climate conditions promoted high grassland productivity and favored the formation of Mongol political and military power.”
“They think the conditions created those needed for a boost in lush growth of grass, which would have fuelled the soldiers’ horses and fattened their livestock. The good weather lasted from 1211 to 1225 – the exact period when Genghis Khan and his armies rose to prominence.”
“Such a strong and unified center would have required a concentration of resources that only higher productivity could have sustained, in a land in which extensive pastoral production does not normally provide surplus resources,” the paper states.”
The incredible leap in logic from 17 tree rings is breathtaking. Maybe some goat herd tethered goats to the trees and the urinated on them. There are many explanations for why a few trees grew better for exactly 14 years.
But even more amazing is that the lesson “we” the gullible should learn is that extreme weather will bring drought!
“The researchers said the trees, some of them more than 1,000 years old, gave them an indication of what the future could hold for the region, with drought and other extreme weather likely to become more common in central Asia.”
The stupidity is alarming. First they claim than natural variation in climate brought warm moist conditions to Mongolia and in fact brought perfect growing conditions … and their conclusion is to worry about drought and extreme weather.
What a waste of grant money.
sunshine hours 
Genghis Khan was crowned last year as the greenest leader in all history, thanks to the bridges, ramps and walls that his soldiers built out of the skulls of the conquered. Mother Nature Network crowned Genghis Khan as history’s greenest leader, thanks to the mountains of stacked corpses (40 million) left by his army.
http://www.mnn.com/earth-matters/climate-weather/stories/was-genghis-khan-historys-greenest-conqueror
Those were the days…
Do we know the cause and effect here? Was it the mass genocide of millions of ecocidal agrarians that caused croplands to revert to ‘nature,’ or was it the razing of cropland by Khan’s army that caused the ‘salad days’ to abruptly end?
I smell a follow-on grant opportunity!
There is a disturbing trend of greenies fantasizing about depopulation. Of course they always assume they will be the ones spared.
Grant Proposal x43789: The Black Death – Mother Natures Revenge!