Not Good for Crops

A worrisome forecast for the world's crops
Studies on rising ozone pollution, shorter winters, and an expanding tropical belt do not bode well for agriculture.

By Robert C. Cowen
If you are concerned mainly with temperature when you think about climate change, your perspective is too narrow.

Think also about other atmospheric changes such as rising ozone pollution. A recent study indicates that its increasing harmful effect on plants could cut the global economic value of crop production by 10 to 12 percent by this century's end. The research projects that regions such as the United States, China, and Europe would become net food importers.

Think, too, of how plants respond to a warmer environment. New research shows that a longer growing season is not always beneficial. Or consider new evidence that the tropical zone already is expanding faster than computer-based climate simulations have forecast.

These examples from the latest research make the point that ecologists trying to anticipate global change still have a lot to learn.

The new ozone projection was a shocker even for the Massachusetts Institute of Technology researchers who conducted it. The study projects that growing worldwide fossil fuel burning will boost global average ozone concentrations 50 percent by 2100 unless emissions are seriously restricted.

Kudzu Pollution

So it's not just an eyesore
Kudzu Plant: Source Of Ozone Pollution?
Scientists Suspect Pesky Vine Of Causing Smog And Global Warming
(AP) Kudzu, the Southern vine that makes Chia Pets of trees and telephone poles, may have yet another unwelcome characteristic: air pollution.

Researchers believe kudzu is releasing ground-level ozone, contributing to smog, breathing difficulties and global climate change.

"If we're right, then it'll be one more big reason to dislike kudzu," University of Virginia researcher Manuel Lerdau said of his preliminary findings.

The fast-growing plant covers an estimated 11,580 square miles in the United States, primarily in the Southeast. Annually, the vine adds 200 square miles to its domain.

Lerdau and fellow researcher Jonathan Hickman of the State University of New York at Stony Brook said they do not have enough data to state with certainty that kudzu warrants a major effort to curtail its growth. They are hopeful of presenting more definitive findings next year.

Kudzu produces two key ingredients of ozone: Its leaves emit a volatile organic compound called isoprene into the air, and its roots convert atmospheric nitrogen into ammonium, some of which can leak into the soil where it is converted by bacteria into nitric oxide.

In the presence of sunlight, isoprene and nitric oxide mix together to make ozone.