Thursday, May 05, 2016

Great Barrier Reef Could be Dead in Twenty Years

Australia's greatest natural wonder, the Great Barrier Reef, is suffering its worse bleaching episode in recorded history.  Scientist warn that because it takes 15 years or more for the reef to rejuvenate after a bleaching episode of this magnitude, the reef could largely be dead by mid-century.  Warming water temperatures are responsible for the bleaching and current temperature trends would produce a bleaching event every two years by 2030.  Global warming has increased sea temperatures off Queensland's coast by 1.8℉ in March.  Corals expel the photosynthetic algae they normally have a symbiotic relationship when warming sea temperatures kick the tiny organisms into overdrive.  It is the algae that gives the coral structures color.  If sea temperatures drop, the algae is able to recolonize their hosts, but not if there is consistent warming. Greenhouse gas emissions have made the current bleaching event, affecting 93% of the reef's corals, 175 times more likely to occur than not.  Damage to the reef seen from aerial surveys ranges from minor in the south to very severe in the pristine north end of the 1430 mile reef [map courtesy Australian government].  A controversial study done in 1999 by Ove Hoegh-Guldberg predicted such a massive bleaching would occur; he told reporters his predictions are now looking conservative.