Abstract: This article examines how Russian imperial ambitions to transform the Kazakh steppe between 1840 and 1914 were shaped by and in turn reshaped understandings of climate. As Russian scientists and administrators encountered Central Asia’s continental climate, with its extremes of heat and cold, they developed theories that recast the steppe’s aridity from an immutable natural barrier into a condition that could be ‘improved’ through European cultivation and settlement. It reveals how environmental theories became instruments of empire. The resulting transformations not only made Kazakhs increasingly vulnerable to the climate, but would set off the changes that would magnify the scale and tragedy of ensuing famines. This history illuminates both the origins of Russian schemes to engineer climate – which would culminate in the Soviet era’s Great Transformation of Nature – and the broader relationship between environmental knowledge and imperial power in the nineteenth century.