New stick to beat developing countries on GHGs

until now, it was believed that methane, from cattle dung and paddy cultivation, was the second biggest contributor to global warming after carbon dioxide. A recent review says soot is the second biggest contributor. Soot has 60 per cent of the effect of carbon dioxide on global warming, and China and India contribute 25-35 per cent of the total soot emissions, the paper says.

Soot, also called black carbon, is primarily produced from the burning of biomass such as fuelwood, cow dung, agricultural waste and coal, and from diesel exhaust; it is the reason behind many health complications. About 80 per cent of rural households in India use fuelwood for cooking. The paper says mitigation methods, involving use of solar cookers, will take care of the cooking needs and reduce carbon emissions.

The review, published in the April issue of Nature Geoscience, analyzes existing literature on observational and computer simulation data related to climate change. It says these studies have limitations. First, they fail to assess the role of soot in atmospheric brown clouds that are a mixture of anthropogenic pollutants