Ozone likely to threaten European forests as climate warms

Climate change is increasingly levels of ozone to the extent that plants in northern and central Europe will be suffering significant damage from the pollutant by the end of this century say Swedish scientists.

"The increased risk of ozone damage to vegetation is mainly due to rising ozone concentrations and higher temperatures in the future," says Jenny Klingberg at the University of Gothenburg's Department of Plant and Environmental Sciences. "The most important effect on agricultural crops is premature aging, which result in smaller harvests with lower quality."

Ozone is very important to life on Earth as any green veterans will remember. In the higher atmosphere - the ozone layer helps keep out harmful ultraviolet solar radiation. It was in order to protect this vital layer that chlorofluorocarbon gases were banned from aerosols and fridges.

Closer to the planet's surface, and to us, ozone becomes a pain and a pollutant that is toxic to both plant and animal life. Car exhaust is the major source of this ground level ozone which is most dangerous to vegetable life, causing stunted growth and lower agricultural yields.

Klingberg's research is the first study to examine not ozone levels in the air, but the path by which the gas reaches plants, through openings in their leaves.

Klingberg said: "The results show that the risk of ozone damage to plants is greatest in central Europe where ozone concentrations are high and climatic conditions promote uptake of ozone through the stomata. Weather and climate affect both the concentration of ground-level ozone in the ambient air and to what degree the stomata are open."

It is possible that some of the damage may be offset by the action of another greenhouse gas, carbon dioxide. As the levels of CO2 increase, plants take up less ozone, but Klingberg warns that this effect is an unknown quantity.