Ozone could increase global warming

Further research into the damage ozone close to the earth's surface can have on plants has led British scientists to conclude that emissions of the gas could be speeding up global warming.

While ozone high in the atmosphere helps shield us from the harmful rays of the sun, it can play havoc closer to the ground.

Scientists from the Met Office, the University of Exeter and the Centre for Ecology & Hydrology have been looking into the precise impact of rising ozone levels and have concluded that it has not received enough attention in climate models which could mean that global warming will be even more severe than previously predicted.

High levels of ozone near the Earth’s surface could lead to significant reductions in regional plant production and crop yields and reduce plants’ ability to absorb carbon dioxide.

Near-surface ozone has doubled since 1850 due to chemical emissions from cars, industry and forest fires.

“Climate models have largely ignored atmospheric chemistry but in this research we have identified a cause of potentially increased warming with elevated levels of surface ozone likely to suppress plant growth,” said the Met Office’s Dr Stephen Sitch, lead author of the research.

Plants and soil are currently slowing-down global warming by storing about a quarter of human carbon dioxide emissions, but the new study suggests that this could be undermined by further increases in near-surface ozone.

As a result more carbon dioxide would accumulate in the atmosphere and add to global warming.

Co-author, Prof Peter Cox of the University of Exeter, said: “We estimate that ozone effects on plants could double the importance of ozone increases in the lower atmosphere as a driver of climate change, so policies to limit increases in near-surface ozone must be seen as an even higher priority.”

Sam Bond

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