Skip to navigation | Skip to content

Mild weather may have propelled Genghis Khan's rise

Genghis Khan

Genghis Khan expanded the Mongolian Empire into the largest contiguous land empire in history in the 13th century during an usual wet spell(Source: Mas'ud b. Osmani Kuhistan/Wikimedia Commons)


An analysis of tree rings spanning 11 centuries shows the conqueror seized power during dry times and was able to expand his empire across Asia during an unusual stretch of good weather.

The years before Genghis Khan's rule were marked by severe drought from 1180 to 1190, according to the study published today in Proceedings of the National Academy of Sciences .


The study results suggests mild temperatures spurred the growth of grasslands, boosting productivity particularly in the the Orkhon Valley, which became the seat of power in 1220, write the authors.

"The transition from extreme drought to extreme moisture right then strongly suggests that climate played a role in human events," says study co-author Amy Hessl, a tree-ring scientist at West Virginia University.



The strand of gnarled, stunted Siberian pines (Pinus sibirica) live in cracks in an old solid-rock lava flow in the Khangai Mountains.




Recent change

The tree-ring data also provides an insight into more recent climate change in Mongolia.

In the 20th century regional climate was wetter than any of the previous 11 centuries, during which time widespread agricultural development occurred.

However, in the early 21st century the region experienced the hottest drought in central Asia for the last 1,112 years, consistent with projections of warming over inner Asia.

This drought rapidly reduced the carrying capacity of the land and saw the migration of 180,000 people to the capital city of Ulaanabaatar, write the authors.

"Unusual decadal-scale events in Mongolia like the Mongol Pluvial and the 21st-century drought had far reaching social consequences including rapid urbanisation and widespread social change."

Projected temperature rises in the future could produce similar heat droughts and have potentially severe consequences for modern Mongolia, they add.

Tom Baerwald, a program director for the National Science Foundation, which funded the research says: "Through a careful analysis of tree-ring records spanning 11 centuries, the researchers have provided valuable information about a period of great significance."


Tags: climate-change, anthropology-and-sociology