GBR Bleaching Already Well Under Way; Already Worse Than 2016 In Multiple Locations

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During early 2017, the region over Australia’s Great Barrier Reef (GBR) experienced its hottest summer atmospheric temperatures on record. Peak water temperatures lag peak air temperatures by about a month. But already, sections of one of the world’s most vital marine sanctuaries are experiencing bleaching and disease. Worryingly, bleaching and heat stress is expanding over the reef at a faster rate than at the same time last year.

(The Great Barrier Reef is already experiencing extensive bleaching in 2017. With warmer waters headed toward the reef over the coming weeks, researchers fear that this year’s coral mortality event could match or exceed 2016’s severe damage and loss. Video source: BBC/Youtube.)

During 2016, the GBR experienced its worst coral bleaching event on record. This severe event followed two years (2014-2015) in which the reef saw less widespread bleaching. A strong El Nino combined with the highest global temperatures ever measured to produce ocean conditions that were too hot to support living corals and many regions saw bleaching and high mortality. In the reef’s northern sections, more than 2/3 of the corals bleached and died out.

Scientists who’d long warned that global warming would put the fate of the great reef at risk, issued an alarm and a call for action. Global temperatures had now reached a threshold that threatened to put Australia’s natural wonder at risk with far greater frequency than ever before. Scientists warned that by the 2030s, ocean temperatures would be warm enough to produce a bleaching event similar to the 2016 die-off every 2-3 years. A separate study indicated that the reef could experience severe coral bleaching through at least 2040 (and well beyond if the world continued to burn fossil fuels and to warm up at such rapid rates).

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(Under human-forced warming the frequency of coral bleaching events and reef mortality is expected to dramatically increase over the coming decades. However, with global temperatures now 1.2 C warmer than 1880s levels, the amount of stress to corals is already remarkably high. Image source: The World Resources Institute.)

EDIT

As of this week, new reports of bleaching were starting to emerge in six GBR reefs in the region of Mission Beach. According to Australia’s Environment Minister Steve Miles:

“Queensland has just experienced its hottest summer on record and above average temperatures are predicted until the end of March. Some corals were still under stress from last year’s bleaching event and that was exacerbated by a warmer than average winter. The next four weeks will be critical and we can only hope that water temperatures will be cooler than the forecast.’’

The six reefs in question, stretching from Cairns to Townsville, already showed 60 percent bleaching — primarily among the more heat-sensitive corals. And the extent of bleaching was more advanced than during the same time in 2016. Over the coming weeks, the pulse of warm water is expected to spread, putting still more corals at risk as the unprecedented ocean heat moves southward through the marine sanctuary.

EDIT

https://robertscribbler.com/2017/03/02/widespread-coral-bleaching-strikes-great-barrier-reef-again-in-2017/#comments