For the first time, researchers have used the historical agricultural record to quantify the effect of air pollution on the Indian farming sector. According to their estimates, a combination of smog and global warming have cut Indian grain yields in half.
The new study, published in the Proceedings of the National Academy of Sciences, analyzed the effects of short-lived climate pollutants (SLCPs) and long-lived greenhouse gases (LLGHGs) on wheat and rice yields in India over a 30-year period. In 2010, the authors write, average yields “were up to 36 percent lower for wheat than they otherwise would have been, absent climate and pollutant emissions trends, with some densely populated states experiencing 50 percent relative yield losses.”
The majority of losses were attributed to the SLCPs black carbon and ozone. According to the Guardian, black carbon is generated mainly by rural cookstoves whereas ozone forms from motor vehicle exhaust, industrial emissions and chemical solvents. Ozone has the direct effect of damaging plant leaves, whereas black carbon indirectly causes damage by reducing the sunlight they feed on. In the last 30 years, the study writes, these emissions “have risen dramatically.”
Statistical modeling suggests that 90 percent of the potential crop loss in India is due to SLCPs, with the remaining 10 percent due to global warming and a lack of precipitation.
While this latest study offers potential yield numbers for India’s agricultural sector, its findings are bolstered by an August report published in the journal Geophysical Research Letters, which showed that air pollution in India has damaged 6.7 million tons of crops – enough to feed 94 million people. This damage was primarily wrought by ground-level ozone, a cocktail of nitrogen oxides, carbon monoxide and volatile organic compounds.
Though India as a whole is making significant progress in developing its solar power capacity, the country still has no significant air quality standards to regulate its current pollution.