A global coral bleaching event is underway that many scientists fear will surpass 1998, the last global coral die-off that bleached and killed 16 percent of the world's coral. Already, rising sea surface temperatures have devastated coral off the coast of Indonesia after ocean temperatures in the coastal waters spiked to 93 degrees Fahrenheit earlier this year.
The record heat and sea surface temperatures so far this year have stressed coral across the globe, bleaching colonies from "Thailand to Texas," researchers report. Many of the bleached coral have already died, and scientists expect more will die in the coming months. Computer models suggest Caribbean coral will get hit next, with "drastic" bleaching expected in the next few weeks.
Regional coral die-off events have been recorded since 1983, a year with a particularly large El Niño weather event in the eastern Pacific and Caribbean. Natural weather variability is clearly a factor in regional and intermittent coral bleaching. But natural causes aren't enough to explain what is now a global and recurring phenomenon. Coral acts as a leading indicator of a warming climate.
It is a lot easier for oceans to heat up above the corals’ thresholds for bleaching when climate change is warming the baseline temperatures,” said C. Mark Eakin, of the Coral Reef Watch at the National Oceanic and Atmospheric Administration. “If you get an event like El Niño or you just get a hot summer, it’s going to be on top of the warmest temperatures we’ve ever seen.”
Coral occupy only a small fraction of the vast oceans, but harbor up to a quarter of all marine species. The impacts of bleaching and dying coral are not only environmental, but economic as well. Described as the "rainforests of the sea," coral are a foundation for a colorful and vibrant ecosystem that support fishing and tourism.
As director of the Global Coral Reef Monitoring Network, Clive Wilkinson monitors the situation on a daily basis. "I am significantly depressed by the whole situation," he says.
A canary in a coal mine, a coral in the sea. Global warming is real.
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