Rain and Steppe Empires

Scholarly debate rages over the role played by climatic factors in shaping steppe empires. Simply put, did good weather (mild winters and rainy springs) result in big herds and expansionist behavior by nomads, or was it rather bad weather (freezing winters and parched springs), that drove desperate herders onto the war path? One extensive survey of weather and the states of war and peace on China's steppe frontier attempted to demonstrate a correlation between weather and politics: nomads attacked China when they suffered from bad weather. (Ying Bai and James Kai-sing Kung, "Climate Shocks and Sino-nomadic Conflict," The Review of Economics and Statistics, vol. 93, no. 3 (2011)). I found this counter-intuitive, because low rainfall meant fewer horses. For the sake of the horse.. the kingdom was lost.

Of course one of the problems for such a study is to measure accurately weather centuries ago, and also to interpret the Chinese chronicles-- which may have had their own reasons for exaggerating the bellicosity of the nomads, or the success of the emperor in maintaining the peace. These problems are discussed in "Rethinking Climate and Conflict in Fragile States" by Hélène Donnat Gonzalez Holguera and Miguel Fajardo-Steinhäuser (2025) A recent study in Science Advances looks at an era closer to the present, analysing the behavior of a steppe empire that is well documented in many sources, including Russian. The science behind the weather analysis is also quite thorough. So what does it tell us? In the 18th century the Zhungar (Also Dzungar) Khanate ruled much of Inner Asia, bordering Qing China and Romanov Russia. More advanced technologically and politically than its steppe predecessors, the Zhungars mastered the production and deployment of artillery, and recruited foreign experts to assist in exploitation of their mineral wealth. At its core, however, it remained a confederation of horse breeders, dependent on grass and water to nurture their huge herds, which included sheep, goats, cattle and camels. In the 1750s The Qing emperor Qianlong famously routed the Zhungars in a series of battles commemorated in copper engravings known as "the Ten victories of the emperor of China." Much of what I knew about Qianlong's success focussed on his meticulous logistical planning, which sustained a huge army of men and animals thousands of miles from their bases. (See China Marches West, Peter Perdue, 2005).

A new paper by Wanru Tang, Keyan Fang and 8 others, "Steppe productivity decline contributed to smalllpox outbreak and the collapse of the last nomadic empire in the 1750s" argues that weather contributed significantly to the fall of the Zhungars. (Science Advances, 2026). Analysing tree ring data over four centuries, they found that the mid-eighteenth century steppe experienced severe dry weather. This data is more robust than the earlier studies which considered reported weather, often remote from the pastures of the nomads. The lack of rain translated directly into scarcity of grass, and decline of the herds on which Zhungar power rested. This physical evidence is corroborated by contemporary accounts of widespread famine. When there had been sufficient grass, and large herds, the Zhungars behaved aggressively towards both Russia and China. They had sufficient horse power to maintain a large army. As the dry period on the steppe began, in the 1690s, the Zhungar khanate increased its aggressive activities, in order to secure tribute to partially offset the effects of drier weather. In the 1750s two catastrophes struck the Zhungars. Increasing dryness depleted their flocks. At the same time, smallpox spread through the malnourished population, killing 40% of the population. I had read that smallpox was introduced by the Chinese as an early form of biological warfare, but this paper argues otherwise. Notable is that Qianglong's armies were vaccinated against the disease. Pete Hesgeth take note. This narrative diminishes, to some extent, the exceptionalism of Qianlong's steppe victories. In any case, the Zhungar khanate disappeared, and the territories became what is now the northern part of Xinjiang province. Ironically it is much greener today than it was when Qianlong conquered it.

What can we conclude? Climate does affect conflict politics. When herding-based stakes enjoyed plentiful rain, they could throw their weight around. When they felt threatened by drought, they could use their residual horse power to launch raids and secure compensatory tribute. But prolonged draughts led ecological and demographic collapse. In this case, it heralded the end of the steppe's last great empire.