Ask NASA Climate | September 22, 2010, 17:00 PDT

Quote of the week

The canary in the coal mine

Bleached brain coral. Photo credit: Liane Guild, NASA Ames Research Center.
Bleached brain coral. Photo credit: Liane Guild, NASA Ames Research Center.
“I am significantly depressed by the whole situation.”

Clive Wilkinson, director of the Global Coral Reef Monitoring Network

What’s Wilkinson talking about? His quote comes from a story in the New York Times earlier this week, reporting that coral reefs are in serious trouble. This year we’re witnessing the second known worldwide bleaching of coral reefs.

Bleaching happens when reefs go into survival mode. The corals cast out the tiny algae that help them thrive and give them their color. Why? Because they’re extremely sensitive to temperature changes, and the oceans are heating up as a result of global warming.

A study published in Nature earlier this year by an international team including NASA oceanographer Josh Willis found that between 1993 and 2008, the upper 700 meters of the oceans absorbed 0.64 Watts per square meter (calculated for the Earth’s entire surface area). Lead author John Lyman, an oceanographer at the University of Hawaii's Joint Institute for Marine and Atmospheric Research, put this into layperson-speak: this is roughly equivalent to the power of two billion copies of the atomic bomb the United States dropped on Hiroshima, Japan, during World War II.

Simply put, the global warming of the oceans is stressing out the reefs. And those that care about them. Coral reefs not only make up one of the richest ecosystems in our oceans, but they are home to a great many fish species and are the backbone of fisheries that feed millions of people.

As NASA oceanographer Gene Carl Feldman has said: “Like the canary in the coal mine, coral can provide an early warning of potentially dangerous things to come."