Rising ozone levels could stunt plant growth

News web pic 2_29.jpg
Rising levels of ozone in the atmosphere could make plants less able to absorb carbon dioxide, scientists have found.

New research suggests that ozone created near ground level as sunlight interacts with pollution from car exhaust and other fumes is stunting the growth of plants. This is an important finding because it would counteract the increase in plant growth anticipated as the concentration of carbon dioxide in the atmosphere rises.

'As CO2 increases in the atmosphere that stimulates plant growth,' Stephen Sitch of the Met Office told Reuters. 'But [researchers] haven't included the other effect, the negative effect of ozone damaging productivity.'

The study means that many computer models of climate change which took account of the increased ability of plants to 'suck up' carbon dioxide under conditions of global warming will have to be altered. The rise in ozone may in fact completely counteract any anticipated increase in plant growth.

The paper concludes that without any increase in CO2 absorption, global temperatures will rise by between 2.4 C and 6.4 C by the end of the century.

This article first appeared in the Ecologist July 2007