Natural Clues to NW Climate History OLYMPIA, WA (KPLU) - Heat wave records were certainly in abundance this week. But there's a caveat. Northwest weather records don't date back very far, relatively speaking. They're spotty prior to the 1940's. Now an Oregon State University researcher is having success using long lived trees and sea creatures to lengthen our climate record. KPLU's Tom Banse reports.

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To you and me, it looks like a big clam shell. But O-S-U ecologist Bryan Black looks more carefully at the Pacific geoduck and can see a climate record in the growth rings. The Northwest's biggest clam species can live as long as 150 years.

Bryan Black: "Geoduck growth increment width is a product of temperature affecting metabolism which drives the shell growth. So you get a warm year and it's a very large growth increment."

Not unlike a tree ring, really. And indeed, Black combines the clam shell data with cross-sections of old growth Douglas firs from inland to improve his accuracy. He's found other proxies for a weather station in the ear bones of long-lived rockfish and freshwater mussels.
The researcher in Newport, Oregon wants to reconstruct the Pacific Northwest climate in the decades before instrument record keeping started. He's most interested in sea surface temperatures. They strongly influence our region's weather.

[Bryan Black: "We're really helping to narrow the uncertainty around sea surface temperature estimates over the length of these geoduck chronologies. So we can more accurately find out how much variability there has been."

The level of precision in this technique is insufficient to say whether this past week's heat wave really set local records for all time. But Black would be able to extrapolate for a given year in the 1800's whether temperatures and precipitation were above or below average.] I'm Tom Banse reporting. © Copyright 2009, KPLU