Food crops damaged by continent-travelling pollution
14 Mar 2012 by Evoluted New Media
Europe loses 1.2 million tonnes of wheat a year because of man-made air pollution sweeping across the continent from North America says a new study from the Universities of Leeds and York.
The study – published in Biogeosciences – also suggests that increasing levels of air pollution from one continent may partly offset efforts to cut carbon emissions in another.
Researchers showed how ozone pollution generated in each of the Northern Hemisphere’s major industrialised regions – Europe, North America and South East Asia – damages six important agricultural crops both locally and downwind.
“This study highlights the need for air pollution impacts on crops to be taken more seriously as a threat to global food security,” said Dr Lisa Emberson, senior lecturer from York’s Stockholm Environment Institute and Environment Department. “Currently air quality is often overlooked as a determinant of future crop supply.”
Enhanced surface ozone concentrations are produced through a combination of hydrocarbon compounds and nitrogen oxides. Researchers calculated projected levels of surface ozone concentration – a powerful air pollutant which damages human health and vegetation by damaging plant cells and inhibiting plant growth.
They used a computer model to predict reductions in global surface ozone if man-made emissions of nitrogen from the three continents were shut off. Using crop location and yield calculations, the team was able to predict impacts on staple food crops – wheat, maize, soybean, cotton, potato and rice – each with their own sensitivity to ozone pollution.
Researchers found Asian pollution dominates worldwide losses of wheat – 50-60% – and rice, at more than 90% and that North American pollution contributes the most to worldwide losses of maize – 60-70% – and soybean at 75-85%. Europe’s pollution on other continents is low due to fewer low pressure systems and weather fronts, which are responsible for transporting pollution across continents.
“Our findings demonstrate that air pollution plays a significant role in reducing global crop productivity, and show that the negative impacts of air pollution on crops may have to be addressed at an international level rather than through local air quality policies alone,” said Dr Steve Arnold, senior lecturer in atmospheric composition at Leeds’ School of Earth and Environment.
