Researchers at Rutgers University in New Jersey, United States, found that cooling of the atmosphere caused crop failures in China in the last 2,000 years, which led to the collapse of ruling dynasties.
In a paper issued in the journal Communications Earth and Environment, the researchers have unveiled that the huge amounts of ash from eruptions prevented sunlight and cooled up the Earth for years at a time. Lower temperatures caused a weaker monsoon, resulting in less rainfall.
We confirmed for the first time that collapses of dynasties in China over the last 2,000 years have been more likely in the years following volcanic eruptions, said Alan Robock, co-author of the paper and a professor at Rutgers University’s Department of Environmental Sciences. There is a complex relationship between the two, as long as there is ongoing warfare and conflict, dynasties are more likely to collapse. A cooling climate can also make conflict more likely, thereby increasing the probability of collapse.”
Over 150 violent volcanic eruptions were reconstructed between 1 A.D. and 1915 A.D. in Antarctica and Greenland based on sulphate levels in ice cores. Researchers compared the data with historical records from China on over 68 dynasties dating as far back as 850 A.D. and examined warfare during those periods.
A volcanic eruption can release millions of tonnes of sulphuric dioxide and ash into the atmosphere. When sulfur dioxide reaches the upper atmosphere, it acts opposite to Greenhouse gases, reflecting sunlight into space and cooling the atmosphere.
According to the researchers, huge eruptions can wreak havoc on medieval societies by simultaneously bringing a colder and dryer climate, impacting the agriculture yield.