Offsetting the change

Climate change resulting from greenhouse gases in countries like China and India is being offset by acid rain, according to researchers from Manchester Metropolitan University's (MMU) Earth Systems Science group.

Curiously, the smog plaguing Asian cities appears to be mitigating one of the worst greenhouse emissions - methane - which is 21 times more powerful as a greenhouse gas than CO₂, and is a by-product of the Asian paddy field.

The British team of MMU's Prof Nancy Dise and Dr Vincent Gauci of the Open University added sulphate to laboratory paddies in an effort to mimic the effect of acid rain on Asia’s most common food crop. The acid rain surrogate reduced methane emissions by up to a quarter.

The reduction in pollution happens during a stage of the life cycle when the rice plant is producing grain. This period is normally associated with around half of all methane emissions from rice and the team found that simulated acid rain pollution reduced this emission by 24 per cent.