Coral Bleaching Comments, April 14 2016

The real time Samoa SST monitoring buoys whose temperature you see are probably SOUTH of Tutuila in the approaches to Pago Pago Harbor?

The hot water is NORTH of Tutuila, Upolu, and Savaii, and has intensified in recent weeks, but is being restrained by a marine thermal front just to the south of the Samoan Islands (West and East). If you’re lucky that front will move northward, but if it moves southward, be prepared for sudden change and bleaching.

On adaptation, we have known for a hundred years that there were coral populations acclimated to local higher temperatures, but that is not the same thing as adaptation to global warming. For example, the corals in the Persian Gulf, adapted to the highest temperatures of all, bleach at the same Hotspot intensity as elsewhere in the world, and in fact almost all of them have already died from repeated high temperature coral bleaching events. The Mariana Islands, which you mention below as a possible haven from bleaching, are far from that, and have also suffered repeated bleaching events.

As you point out, a great deal of publicity, and funding, has been given to those who are saying what people want to hear: “no problem, resilient corals will just adapt to global warming”. If corals were really adapting we would surely have seen a change in the thresholds since 1982? If thermal adaptation is really out there, it is still buried in the noise.

Time will tell if coral adaptation is actually happening, but so far I see no convincing evidence of any change in the HotSpot bleaching temperature-time thresholds that I worked out from satellite data in the 1980s, those thresholds still work just as well now to predict bleaching, and there has not been any noticeable change in them yet, although there are certainly less and less of the more sensitive corals around to bleach!

Claims have been made that corals in the northern third of the Great Barrier Reef in particular were already adapting their thresholds or were more resistant to high temperature bleaching. What we are hearing so far about the current bleaching event indicates severe coral mortality, more than 50%, has already happened, even though the mortality is not yet over, and this was only a mild bleaching event in term of the HotSpot intensity times duration. In fact the thermal stress in the GBR was much less than that suffered by most other areas being affected in this El Niño. If anything this extreme mortality response to so brief a stress seems to strongly suggest that either these corals are NOT more resistant as claimed, but if anything, more sensitive!

Time will also tell how the corals in many other places being affected, most not yet being reported, actually respond, because many if not most of those locations suffered greater thermal stress than the GBR did this year. We won’t know until the end of the year.

In our reviews of the global patterns of coral bleaching and HotSpots since 1982, specifically those in 1998, and the 1987 (2nd Global) Bleaching Event, Ray Hayes, Bert Williams, Don McAllister and I concluded this would happen again in the next major El Niño. Indeed, so had Peter Glynn back after the First Global Bleaching Event in 1982. We simply were lucky that the next El Niño, which should have come around 4 years later, took 18 long years to return! There’s no surprise in what is happening now, and coupled with global warming, this event could kill most of the world’s remaining corals this year. Time will tell.

The world has fooled itself that mass coral bleaching was “unexplained” for three decades after it was clear that coral reefs were the most vulnerable ecosystems to global warming, were already at their upper temperature limit, and could take no further warming. All the governments, funding agencies, and BINGOs (Big International NGO, like TNC) have wasted money on marine “protected” areas full of dying corals which were proclaimed to be “resilient” by their managers. Corals are dying just as fast in MPAs as outside them: In 60 years of diving all over the world I’ve never seen a marine protected area with more corals in it than if it had never been protected at all!

There has been ZERO funding to prepare for the severe bleaching events we knew would come by preparing with Biorock Coral Arks, shown in 1998 to have 1600% to 5000% higher coral survival from severe high temperature thermal stress than nearby corals, except in Indonesia and Panama, run without funding by community groups.

Hopefully at the end of this Global Bleaching Event (which is very far from the third!) we will learn the lessons we have repeatedly failed to learn from all the preceding ones! But unfortunately for many, if not most, places it will unfortunately be too late.

Tom Goreau