Editor's Summary

16 August 2007

Ozone and global warming

Plants and soil are currently slowing down global warming by storing about a quarter of human carbon dioxide emissions, but this mitigating effect could be undermined by increases in near-surface ozone. Unlike high-altitude ozone, which blocks harmful ultraviolet rays, low-level ozone damages plants, reducing their capacity to take up carbon dioxide and accelerating global warming. Many climate models include a warming factor for low-altitude ozone as a weak greenhouse gas, but not its effect on vegetation. A new study suggests that projected increases of ozone concentration from industrial sources will markedly reduce plant productivity. This indirect effect could contribute more to global warming than the direct effect of ozone as a greenhouse gas.

Letter: Indirect radiative forcing of climate change through ozone effects on the land-carbon sink

S. Sitch, P. M. Cox, W. J. Collins & C. Huntingford

doi:10.1038/nature06059

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