Publication Date March 30, 2017 | NOAA Climate.gov

Second year of widespread bleaching underway on the Great Barrier Reef

Coral Sea
Thermal stress around the Great Barrier reef from January-March 2017. NOAA Climate.gov image by Dan Pisut, based on NOAA Coral Reef Watch maps.
Thermal stress around the Great Barrier reef from January-March 2017. NOAA Climate.gov image by Dan Pisut, based on NOAA Coral Reef Watch maps.

In May 2016, Climate.gov wrote about a record-breaking coral-bleaching event on Australia's Great Barrier Reef, and discussed the low likelihood of significant long-term recovery. This was published in the cover paper in Nature in March 2017, just as Australia's Great Barrier Reef Marine Park Authority announced continued bad news: widespread coral bleaching was occurring for the second consecutive year.

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On March 24, 2017, Australia's Great Barrier Reef Marine Park Authority stated that in January, it started fielding coral-bleaching reports from park rangers and reef visitors for locations as far south as the waters north of Fraser island, the Marine Park Authority and James Cook University followed up the reports with spot checks, flyovers, and comprehensive aerial surveys.

Because so much coral in the north died in 2016, it was difficult to see the 2017 bleaching there from the air, according to NOAA coral expert Mark Eakin. But according to the Marine Park Authority website, a total of 54 in-water spot surveys of six reefs between Cairns and Townsville in late February revealed signs of thermal stress at all six reefs. As of late March, coral bleaching appeared most severe in the central region of the Great Barrier Reef. Toward the south, bleaching appeared more moderate.

While acknowledging cause for concern, the Marine Park Authority reminded its visitors that the Great Barrier Reef remained a natural wonder with "abundant living coral."