Hood River News

By ESTHER K. SMITH
News staff writer
June 3, 2006

There’s no doubt about it: the global climate is changing.
It’s important to know that point, though the subjects of global warming and the greenhouse effect have been made into political issues, Patrick J. Bartlein, Ph.D., a professor and climatologist at the University of Oregon, told a Hood River audience recently.

“Any way you look at it, instrumental data shows a warming trend,” he said, “and we need to understand how climate works so we understand it before the new climate gets here.”

Bartlein was invited to Hood River by Hood River County School District’s Community Education to present “Global Warming: Recent Developments and the Outlook for the Pacific Northwest,” at an evening lecture last week at the Hood River Middle School cafeteria.

Bartlein is a specialist in paleoclimatology and environmental modeling. He says that climatology has changed a lot since he became interested in it as a boy.

“Climatology used to be just getting data and talking about averages,” he said. “Now as we look at the data we see big changes underway.” And the best way to understand those changes, he said, is by looking at climate models.

The National Oceanic and Atmospheric Administration defines climate models as “computer-based mathematical models which simulate, in three dimensions, the climate’s behavior, its components and their interactions.” According to its Web site, if the model is considered to do a good job at representing modern climate, then certain parameters can be changed, such as the concentration of greenhouse gases, which helps us to understand how the climate would change in response.

“Models do a pretty good job at simulating past climates, which makes me think they’ll do a pretty good job of predicting the future climate,” Bartlein said.

Since instrumental data only goes back so far, scientists rely on paleoclimatic data to see what past climate behavior was like.

According to the NOAA Web site, many natural phenomena are climate-dependent (such as the growth rate of a tree) and provide natural “archives” of climate information: sources like tree rings, ice cores, corals, lake sediments, etc. Combining different types of paleoclimatic records enables scientists to gain a near-global picture of climate changes in the past, the Web site explains.

Worldwide, as glaciers melt and oceans warm up, the sea level rises. As air gets warmer, it holds more water, so warmer weather is wetter weather.

What do these warming trends mean to the Northwest?
If the trend continues, he said, based on climate models, sub-alpine areas would disappear and there would be an expansion of areas covered by conifer forests — partly from the warming, and partly from the increase in carbon dioxide (plants like it). There would be a continuation of the trend toward earlier snowmelt; more winter precipitation.

One thing you can say for sure is, it’s going to be different, he said. The question is, how different?

“We actually understand a lot less about climate now than we did 15 years ago,” Bartlein said. “The more we learn, the more we have to unlearn — that’s why I find it interesting. In the space of my career we’ve unlearned as much about climate as we’ve learned.”

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To learn more about climate change, visit:
http://geography.uoregon.edu/envchange/index.shtmll.
To view pdf files of Bartlein’s slide show, visit:
http://geography.uoregon.edu/envchange/gwhr.