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Air Pollution in India Impacts Crops, says Study

06 November 2014

INDIA - Air pollution has cut India’s projected grain yields by half, the research paper published in the Proceedings of National Academy of Sciences said recently.

The paper titled “Recent Climate and Air Pollution Impacts on Indian Agriculture" authored by Jennifer Burney, scientist at the University of California said that while temperature’s gone up in the last three decades, the levels of smog and pollution have changed much more dramatically.

This was the first time anyone looked at historical data to show that these pollutants are having tremendous an impact on crops, the paper adds.

The study shows that India has already been negatively affected by recent climate trends. However, anthropogenic climate changes are a result of both global emissions of long-lived greenhouse gases (LLGHGs) and other short-lived climate pollutants (SLCPs).

Two potent SLCPs, tropospheric ozone and black carbon, have direct effects on crop yields beyond their indirect effects through climate; emissions of black carbon and ozone precursors have risen dramatically in India over the past three decades, the study adds.

The paper said: “Our statistical model suggests that, averaged over India, yields in 2010 were up to 36 per cent lower for wheat than they otherwise would have been, absent climate and pollutant emissions trends, with some densely populated states experiencing 50 per cent relative yield losses.”

“[Our point estimates for rice (−20 per cent) are similarly large, but not statistically significant.] Upper-bound estimates suggest that an overwhelming fraction (90 per cent) of these losses is due to the direct effects of SLCPs. Gains from addressing regional air pollution could thus counter expected future yield losses resulting from direct climate change effects of LLGHGs,’ the paper adds.

Rising temperatures because of increased emissions of long-lived greenhouse gases (LLGHGs) have had and will continue to have significant negative impacts on crop yields.

However, other climate changes caused by short-lived climate pollutants (SLCPs) are also significant for agricultural productivity. The SLCPs black carbon and ozone impact temperature, precipitation, radiation, and—in the case of ozone—are directly toxic to plants.

This study provides the first integrated historical examination of the role of both SLCPs and LLGHGs on wheat and rice yields in India, and finds that the majority of losses are attributable to SLCPs. Agricultural co-benefits from SLCP mitigation are expected to be large, and because SLCPs have short atmospheric lifetimes, almost immediate, the paper revealed.

Jagdish Kumar, Editor

Jagdish Kumar, Editor

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