As world warms, vegetation changes may influence extreme weather

22 May 2005 | 13:44 Code : 5110 Geoscience events
A Purdue University climatologist has found that vegetation can significantly
A Purdue University climatologist has found that vegetation can significantly affect extreme weather, a discovery that could add a new piece to the global warming puzzle.

This figure of the western United States shows the impact vegetation changes resulting from global warming have on extreme climate events when compared with the effect of global warming alone. As vegetation responds to the greenhouse effect, the number of extremely hot days could double in frequency in semi-arid areas, such as the Great Basin and the California coast. (Diffenbaugh lab)

Noah S. Diffenbaugh has found that extreme weather events, such as storms and heat waves, can vary substantially in frequency and severity in a region depending on how vegetation responds to global warming. This is believed to be the first study to indicate that as vegetation responds to climate change, those changes in ground cover may affect where and how often extreme weather events occur. While climate scientists have theorized that this relationship exists, Diffenbaugh said, this study gives further credence to the idea that interactions among land, air and sunlight are more complex than we might imagine.

"Earth's climate is all about relationships, and this study shows that ground cover plays a significant part in determining changes in climate extremes," said Diffenbaugh, who is an assistant professor of earth and atmospheric sciences in Purdue's College of Science. "We are accustomed to hearing that greenhouse gases affect climate, but they are not the only factor we should consider. Our climate models also must incorporate the effect of vegetation if they are to capture the full scope of reality."

Diffenbaugh said he conducted the research, which appears in this week's issue of the journal Geophysical Research Letters, because extreme climate events are one of the most important variables in human interaction with the environment.

"People have suspected for some time that the greenhouse effect can change how often extreme events occur and how severe they are," he said. "We also know that climate change will affect what vegetation grows where and that those vegetation changes can feed back to further change the mean climate state. But this is the first insight we've had into whether those vegetation changes will also change the frequency and magnitude of extreme temperature and precipitation events, such as droughts and severe storms." 

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