Beijing ordered scientists to refute study blaming empire's demise on drought
It has been a millennium since the sun set on the golden age of the Tang dynasty, but the political fallout of its decline is still being felt today in a debate over exactly what brought the empire down.
In a paper published this year in Nature magazine, a German-led research group suggested an escalation of wintry monsoons caused by a global climate change was the catalyst for the empire's collapse.
However, linking global climate change with government collapse touched a nerve with some Chinese officials. So the government pushed mainland scientists to collect evidence and develop a theory that proved the German scientists were wrong. The results, regarded by anonymous academic reviewers as 'strong' and 'scientifically robust', were published this month in the same magazine.
The German team, led by geologist Gerald Haug of the University of Potsdam's Institute for Geosciences, concluded that between AD700 and AD900, winter monsoon winds in China were stronger and summer rainfall weaker than normal, leading to prolonged droughts and a decline in crop yields. Less food then magnified the impact of losing a war with the Arabs, which led to a rapid decline of the empire.
They based their conclusions on titanium levels in sediment in Lake Huguang Maar, on Guangdong's Leizhou Peninsula, which they believed represented the amount of dust carried by winds from the north.