Feeding The World By Cleaning The Air

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Redwood Valley

NASA Funded Study November 23, 2009: “Feeding the world by cleaning the air…study ties heavy regional haze to reductions in crop production.” http://earthobservatory.nasa.gov/Newsroom/view.php?id=20806

“A new study suggests that cleaning up the air may help to feed the world. Published in the November 23, 2009, issue of Proceedings of the National Academy of Sciences, the study found that heavy regional haze in… important agricultural areas may be cutting food production there by as much as one-third. Covering a million square kilometers or more, the haze scatters and absorbs solar radiation, reducing the amount of sunlight reaching key rice and winter wheat crops. That decreases plant growth and food production…”

“For crops that are irrigated and fertilized, there is often a direct correlation between how much is grown and how much sunlight reaches those crops,” said Dr. William L. Chameides, professor in the School of Earth & Atmospheric Sciences at the Georgia Institute of Technology. “In China there is a significant amount of haze that reduces the sunlight reaching the surface by at least five percent, and perhaps as much as 30 percent. The optimal yields of crops in China are likely reduced by the same percentage.”

“…Extensive studies by agricultural researchers have documented the relationship between crop production and the sunlight received… Large-scale regional hazes exist in other developing countries, suggesting food production may be similarly reduced in India and African nations that are also struggling to feed their people… Any economically developing or developed country will have these large regional hazes associated with burning,” Chameides explained. “Burning fossil fuels, burning wood and burning biomass for clearing fields causes production of a significant amount of haze that leads to a reduction in the solar radiation reaching the earth’s surface…”

“…The same effect has been measured on the East Coast of the United States… Researchers have long known that air pollution harms human health and damages crops, but the complexity of those factors has made it difficult to quantify the true cost. Reductions in crop production tied directly to haze-induced sunlight reductions provide the kind of cause and effect that can be used in balancing food production against the costs of improving environmental quality… In tallying up the balance sheet, policymakers want to make sure they have everything in each column,” he explained. “This is something new that goes on the side of why it pays to clean up air pollution…”

“…Crop reductions predicted by the study provide a lower limit of the effects caused by air pollution. Adding to the direct effect of reducing sunlight are indirect effects, such as aerosol-induced cloud cover and increased reflectivity, which further reduce the sunlight reaching plants. Finally, harm from growth-stunting ozone, acid deposition and other air pollutants also worsen the impact of poor air quality…”

“…Fuel for cooking and home heating also tends to be dirty. Agricultural practices involve burning crop debris at the end of the growing season…”

“…The research was… supported by the U.S. National Aeronautics and Space Administration (NASA) as part of its long-term climate studies…”