current issue web exclusives blog multimedia archive subscribe advertisers
Feature Articles
Editor's Note
Audubon View
Letters
Field Notes
Audubon Family
Audubon In Action
Currents
Green Guru
Incite
Reviews
One Picture

Bookmark and Share

Field Notes
News Articles
Birds: Planning Ahead
Climate Change: Time Capsule
Interview: The Naturalist
Wildlife: Scare Tactics
Oceans: Head Above Water
Birds: Too Hot

Briefs
Earth-safe sex; cactus bandits; hitting the fossil jackpot; prairie dog lingo; more

Climate Change
Time Capsule

Click on the images above for a slideshow.

Two of the most powerful tools scientists have for learning about global warming are multimillion-dollar satellites and clams. Yes, clams. Researchers use the shells of saltwater bivalves called geoducks, which can live for 150 years, to reconstruct past sea temperatures. Corals, pollen, and ice cores, too, are among the many natural archives that help researchers paint a picture of ancient aquatic, atmospheric, and terrestrial conditions in order to make accurate forecasts. “The way that earth behaved in the past is a good indicator of how it might behave in the future,” says Terrence Quinn, a paleoclimatologist at the University of Texas at Austin. Our 150-year-old instrumental climate record reflects a “climate that was already perturbed by anthropogenic carbon dioxide,” he says. To see what the planet was like farther back, scientists look at 400-year-old Douglas firs along the Pacific Coast or ice in Antarctica that accumulated over 400,000 years. “Maybe we’ll have a 200-year-long record [in a coral fossil from] 5,500 years ago,” says Quinn. Combining individual coral records gives an idea of “what El Niño was doing over the last 10,000 years.” Piecing together different proxies—such as both tree rings and geoducks over the same period—may provide even more powerful results. “When they start telling you the same thing,” says Quinn, “then you can really have confidence.”—Lynne Peeples

Back to Top