El Viejo: The Old Man of the Sea

Introduction:

John Steinbeck's novel, Cannery Row, is about the economic hardtimes caused by the collapse of the sardine fishery off California in the 1940s. Nobody noticed at the time but the sardine fisheries were declining precipitously all around the Pacific Ocean. This was part of a larger pattern. For about twenty-five years the Pacific Ocean is warmer than average by a degree Celsius or so, and then the entire basin is cooler for about twenty-five years. The collapse of the sardine fishery that Steinbeck wrote about occurred when the cool water regime of the 1930s and 40s changed to a warm regime.

This ocean-wide behavior is subtle and by no means obvious. The picture only emerged after data had been collected long enough, and then only after global warming effects were subtracted from the signal. However it was obvious to the animals that live in the ocean. In fact the wild swings in fish populations were one of the first clues that ocean as a whole was behaving oddly.

It turns out the Pacific was in a cool phase from 1900 to 1925, a warm phase from 1925 to 1950, cool again from 1950 to 1975, warm from 1975 to the mid 1990s, and now it is in a cool phase. If El Niño, which has a period of three to four years, means The Baby or the Little One, then this longer period, basin-wide change in the ocean should be called El Viejo, the Old Man.

This improved understanding of the ocean's behavior has important implications for fisheries management, weather forecasting, and climate change. We spoke with Franscisco Chavez about his article in Science on El Viejo.

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