June 12, 2012
You can’t talk about coral in the Galapagos without talking about the atmospheric phenomenon called El Niño Southern Oscillation (ENSO). Normally, west-blowing trade winds push warm waters into the western Pacific Ocean. Every four or five years on average, though, the trade winds die down, or even reverse, and these warm waters move east as far as the west coast of South America, raising water temperatures as much as 7 to 10 degrees C.
ENSO can last anywhere from nine months to two years—usually about a year and a half—but while it does, it affects weather around the world, and especially around the Galapagos. The phenomenon was called El Niño (“The Child” in Spanish) because it usually starts around Christmas. It’s considered to be linked to global warming, since it has been happening more often and with more drastic results as global temperatures have risen, but the root causes are still unclear.