IF THERE were a silver lining to the massive cloud of pollutants hanging over India, it would be that this brown haze is doing farmers a favour by counteracting global warming. In fact it does more harm than good, and getting rid of it would probably increase the rice harvest.
Between October and May, a 3-kilometre-thick brown haze sits over much of south Asia and the northern Indian Ocean. Caused mostly by urban emissions and wood fires, this dirty cloud cools the region by reflecting sunlight back into space. Unfortunately it also reduces evaporation, leading to a reduction in monsoon rainfall.
When Jeffery Vincent of the University of California, San Diego, and his colleagues combined data on India鈥檚 rice harvests with a climate model they found that the harvests would be up to 10.6 per cent higher if the brown haze wasn鈥檛 there, and 14.4 per cent higher if the detrimental effects of global warming were removed too (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0609584104).
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Cleaning up the brown haze will have a positive effect, says Vincent. 鈥淎ny negative impacts of intensified warming on rice harvests would be outweighed by the positive impacts of greater rainfall due to a lessening of the brown cloud鈥檚 drying effect.鈥�
