How does rising atmospheric CO2 affect marine organisms?

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The Recent Climate Regime Shift in the Northeast Pacific
Peterson, W.T. and Schwing, F.B.  2003.  A new climate regime in northeast Pacific ecosystems.  Geophysical Research Letters 30: 10.1029/2003GL017528.

What was done
The authors describe a number of persistent changes in atmospheric and upper ocean fields and ecosystem structure that suggest that a major climate regime shift occurred in the northeast Pacific Ocean and adjacent coastal areas in the latter part of 1998, which shift is similar (opposite) to shifts observed there in 1947 (1925 and 1976).

What was learned
Peterson and Schwing report that "upwelling-favorable winds strengthened over the California Current (CC), and winds weakened in the Gulf of Alaska (GOA)," while "coastal waters of the CC and GOA cooled by several degrees, and the Pacific Decadal Oscillation (PDO) reversed sign and remained negative through summer 2002."  As a result, they say that "zooplankton biomass in the northern CC doubled and switched from warm to cold water species dominance, coho and Chinook salmon stocks rebounded, and anchovy and osmeriids increased."  In addition, they report that recent surveys of the GOA reveal that the ecosystem there has been transformed as well.

What it means
With respect to the northeast Pacific, the observed changes, in the words of the authors, "imply a shift to stronger coastal upwelling and greater than normal southward transport in the CC."  With respect to the planet as a whole, the changes could well presage a return of cooler temperatures, in light of the dramatic shifts in global temperature trends that commenced at approximately the same times as the documented climate regime shifts of 1925 (warming), 1947 (cooling), and 1976 (warming), which can be readily reproduced from the Global Historical Climatology Network and Jones et al. databases of the World Temperatures section of our website.

Reviewed 2 June 2004