Are recent environmental threats to coral reefs from rising sea levels unfounded?
In Panama’s gulf on Isla Contadora last year we were stunned to find huge coral reefs alive and well where tidal range is more than 20 feet, in water so hot that it almost felt scalding upon entry. If El Nino caude “bleaching” due to excessively high temperatures, we utterly failed to find any evidence of it. – Fred Crowe, San Diego ANSWER: Your question identifies two possible threats to coral reefs, both of which are linked to global climate change: rising sea level and increase in seawater temperature. Sea level rise itself is not expected to devastate coral reefs. Larger waves may cause erosion of less protected reefs, but rising sea level also permits reefs to expand vertically. On the other hand, temperature increases can lead to mass bleaching, as occurred in 16 percent of the world’s coral reefs in 1998 (an El Niño year). Mass bleaching is believed to be a relatively recent phenomenon. Since 1979, there have been six such events. Bleaching occurs when the individual coral polyp
