Posthuman Blues

Smog is changing the face of Earth's water cycle

Smog may be having dramatic effects on the planet's water cycles, and in ways not previously apparent, researchers have warned. Revealing one aspect of this, they have shown that urban pollution and other aerosols have significantly reduced rainfall over hills in central China.

"Pollution is reducing rainfall in the areas where people need it most," says Daniel Rosenfeld, at the Hebrew University of Jerusalem in Israel. "Communities in semi-arid regions rely on the water from rain and snow that fall on mountains, sometimes hundreds of kilometres away. But the combination of the hills and the air pollution emitted by the same people means that the some of moisture in the clouds is evaporating before it ever hits the ground."