The Climes They Are A-Changin'

Some climate models predict that Northwest temperatures may increase nearly seven degrees Fahrenheit in the next century. Along with changes in precipitation, these higher temperatures might give western Oregon hotter, drier summers like those now found in Sacramento but wetter winters like those that shroud the Olympic peninsula. "We haven't seen these kinds of conditions for thousands of years," says University of Oregon geography professor and climatologist Pat Bartlein.
What's behind these epochal changes? Bartlein explains that the climate of a place results from the globally interconnected forces that shape it...interactions among the atmosphere, oceans, ice sheets, the biosphere and, in the past 100 years, human beings.
"The effects on climate brought about by humans--primarily through greenhouse warming--seem to be increasing in scope and are potentially devastating," says Bartlein. "We're in a race to understand the changes in climate before they happen."
But the race is more difficult than it once appeared. "Fifteen years ago climatologists generally felt that we would soon understand the 'climate system,' but now we are appreciating more and more fully the complex and often subtle nature of that system," he says.
Bartlein sheds light on these subtleties by researching how past changes in large-scale climatic controls are felt at the regional and landscape level. "Our research shows that past temperature and rainfall changes have produced dramatic changes in vegetation," he says. "From this we know that the predicted changes in Northwest climate will significantly affect the region's plant life."
This link was firmly established in his recent collaboration with fellow UO geography professor Cathy Whitlock. By examining pollen in sediment at Carp Lake in southwest Washington, Whitlock established an unbroken history of local plant life dating back 125,000 years. She and Bartlein correlated this record with the known history of climate controls. At times the climate and vegetation at Carp Lake have switched dramatically, for example, between warm, moist forest and cold, dry steppe environments--sometimes within a few decades.
"Changes like this, accelerated in the next century by the Greenhouse Effect, could have big implications for the agriculture and forestry that are such important parts of the Northwest economy," Bartlein observes.
Often in the headlines, El Niņo is a set of unusual climatic conditions in the tropical Pacific that ultimately influence weather patterns in the midlatitudes, including Oregon. Bartlein is currently using El Niņo as a teaching tool in his and Whitlock's introductory physical geography class. By monitoring a wide variety of resources he has gathered on the World Wide Web, Bartlein's students closely track El Niņo's development.
"It clearly demonstrates the global nature of climate by showing that our weather is directly connected to weather patterns in South America, the Pacific, and Asia," he says. "In the long run, El Niņo-produced climatic variations are smaller than those that could result from global warming, but their day-to-day effects are quite remarkable and instructive." Nevertheless, it is the long-term effects of greenhouse warming that concern Bartlein most.
"Climatologists are doing all we can to discover the mechanisms and implications of this change before it is too late to take steps to reduce the effect or adapt to the change," he says. "This is not a race we can afford to lose."

Back to INQUIRY, Fall 1997

©1997 University of Oregon