In his July 11 letter, John K. Carlisle of the National Center for Public Policy Research inaccurately blames the decline of Pacific Northwest salmon population solely on "natural increase in the ocean temperature and not human activities," such as global warming.
He is correct that a warmer ocean is a culprit in declining salmon stocks, but to claim that human activities, including global warming, have nothing to do with the decline is to ignore the obvious. Mr. Carlisle misrepresents the recent findings of several University of Washington studies on the warming cycles of the oceans and the factors affecting salmon populations.
While salmon face numerous threats from human activities in their freshwater habitat, a warmer Pacific Ocean also has been shown to harm salmon during their oceanic phase. Recent analyses have identified a 20- to 30-year cycle of warming and cooling in the Pacific; however, this is but one of the many processes influencing ocean temperature. The El Nin~o-La Nin~a cycle warms and cools the Pacific every few years. Global warming is generally viewed as contributing to a monotonic increase in ocean and land temperatures. As such, global warming would mitigate any benefit to salmon of a natural cyclic cooling.
Mr. Carlisle's view that global warming has not contributed to ocean warming is contradicted by the more than 2,000 scientists who make up the Intergovernmental Panel on Climate Change and who concluded: "The balance of evidence suggests a discernible human influence on global climate." Mr. Carlisle appears to be content to stick to the status quo and hope that the salmon will reappear. For the sake of the Northwest salmon populations, let's hope that the government will heed the warnings of scientists worldwide and address the problem of global warming.
STEVEN R. HARE
INGRID ANN CHAPMAN