Who farted?

We’ve all done it: released a little gas inappropriately, like in a crowded lift, for example (blush). How much worse, if the gas was to form a smelly brown cloud right above your head – a bit harder to pretend it wasn’t you wot done it, eh.

That’s exactly what India is rather misguidedly trying to pull off. Kapil Sibal, India’s science minister has dismissed as “propaganda” a United Nations report into the annual brown haze that stretches in mile-long clouds across Asia. This winter fug of filth is due to kerosene stoves in kitchens across Asia, combined with pollution from traffic and industry across the region, the UN report says – and it is not a controversial view. Except in Asia, where even scientists are self-censorious on what has become a highly emotive issue. Indians point out rightly that they have much lower per capita greenhouse gas emissions compared with Europe or the US. Carbon dioxide and methane are invisible, of course. The brown haze is a collection of soot (unburned carbon), sulphates and other particulates from incomplete combustion of fuels from coal to kerosene.

The haze is horrible for the region’s health and it may have consequences for glacier melting and the Asian monsoon. But every brown cloud has a silver lining: the clouds have a local cooling affect on the region below (because some of the particulates absorb the Sun’s heat, and others radiate some of it back), and studies have shown that the way that sulphate particles scatter light can enhance photosynthesis in plants. Photosynthesis removes carbon from the atmosphere.

So maybe India should own up to its farts.