[Coral-List] Evidence that ocean warming has caused most Caribbean coral loss

[Steve Mussman]

 Dear Mike ,

You make a number of good points and I agree with you although I'm trying my best to resist accepting what I consider to be your realistic/pessimistic position on the future of coral reefs. It is just too painful a picture to envision so for now I choose to look away. Sometimes even focusing on the next resurgence that I like to imagine will occur over geological time. We certainly did miss opportunities to speak with a forceful, unified voice early on, but I attribute that to our tendency to unify only when a situation rises to the level of an undeniable crisis. Coral reefs now seem to be approaching that tipping point so the question has the be is there single mindedness among coral scientists as to what must be done and can a message be articulated that can save the day or at least make it appear as if we tried?  I don't presume to have the answers, but at this point it appears that reducing carbon emissions holds out our best chance.  That doesn't mean that addressing local stressors is futile or meaningless, only that such efforts should be framed in such a way that there is no ambiguity - if we are to have any real hope of preserving what's left of our coral reefs we must address anthropogenic climate change. I come at this from the diving industry where a message has evolved suggesting that protecting marine ecosystems equates to increasing MPAs (without limiting diver access), removing plastic debris, controlling lionfish populations and protecting sharks and rays - all worthwhile endeavors, but without clear recognition of the overriding impacts of climate change it seems to me to be nothing more than a cruel facade.  It's as if a powerful line from a movie rules the day. "You can't handle the truth!"

Regards,
Steve


Sent from my iPad

> On Apr 27, 2017, at 12:35 PM, Risk, Michael <riskmj at mcmaster.ca> wrote:
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> Steve:
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> 
> There is certainly little to disagree with in your statement. I take an even more nuanced and pessimistic position-if it is indeed possible to be more pessimistic than “looming extinction.”
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> Some years ago, I posted on this same list comments to the effect that sure, global warming will put an end to coral reefs: but it really will only be kicking over the edge of the cliff those poor sad remnants that remain after we humans have messed with them.
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> We need to bear in mind that the world had already lost a lot of reefs, perhaps more than half the original total, by the time climate change began to ramp up. Yes, undoubtedly, we need to band together and speak with one voice about reducing outputs of carbon dioxide. At the same time, I wonder: where was that unanimity of purpose in the past, when the impacts of land-based sources of pollution were obvious? Reef biologists chased after various hypotheses-the reefs will come back if only the fish come back, or if the urchins come back, or… while ignoring the gorilla in the room. 
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> I do not really understand why this happened. Perhaps there was fear to challenge vested interests; perhaps there was money to be made consulting for developers and saying nutrients were unimportant; perhaps the trees of individual careers were pursued inside the forest of gathering decline. Perhaps the biologists who dominate this field were loath to tackle aspects of chemistry and geology involved in pollution and sedimentation studies.
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> Those really interested in maintaining reefs need to bear in mind that there have been (to the best of my always-incomplete knowledge) only two studies on what happens to reefs if you improve the water quality: one Caribbean, one Pacific. In both cases, the reefs improved. In neither case should this have come as a surprise.
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> 
> In short, I agree with you that we need a unified front, and my opinion is that the need is all the greater because there was not a unified front 30 years ago. We have lost the opportunity to see how well truly unstressed reefs respond to ocean warming. The news from the Northern GBR is truly appalling-but as Charles says, recovery is another story.
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> I echo Charles’ sentiments, that we are conditioned by the reefs we have seen. To me, a trip into the future was always epitomized by the transect going from the outer Pulau Seribu (Thousand Islands) into the harbour at Jakarta. One goes from lush coral islands (though severely over-fished), past impoverished reefs, past some reefs that are now no more (see Tom Tomascik’s poignant descriptions) and finally into an azoic sea-floor out of the Archean. That’s what the future holds.
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> 
> Mike
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>> On Apr 26, 2017, at 11:41 AM, Steve Mussman <sealab at earthlink.net> wrote:
>> 
>> Dear John and Mike,
>> 
>> I ask this respectfully,  don't you both (as well as the vast majority of your colleagues) ultimately arrive at the same conclusion? 
>> Correct me if I'm wrong, but regardless of how we got here, don't you agree that it is ocean warming that now represents the consummate threat?   I may be interpreting things incorrectly, but It seems to me that at this point we need a unified message reflecting the urgency of addressing this particular issue. 
>> 
>> At the same time we can all remain supportive of the various efforts aimed at addressing local stressors.
>> 
>> Regards,
>> Steve    
>> 
>> 
>> Sent from my iPhone
>> 
>> On Apr 25, 2017, at 8:50 AM, Bruno, John <jbruno at unc.edu> wrote:
>> 
>>> Dear Mike, thank you for your ongoing interest in this topic and my post..
>>> 
>>> "the Caribbean had already lost more than half its reefs before water temperatures had increased by more than a fraction of a degree”
>>> 
>>> This is a common misconception from folks unaware that global warming began many decades ago. Please have a look at the NOAA data plotted in this figure from my post:  http://theseamonster.net/2017/04/caribbean-bleaching/nclimate2915-f4/  Or the graphics in Kuffner et al 2014 below it. These data should sort you out. The Caribbean had clearly warmed significantly by the time mean coral cover had been roughly halved (around the mid-1980s). Also, we haven’t lost any reefs yet, what we’ve lost is coral cover (and fish biomass).
>>> 
>>> Iv’e dove near Havana and I agree - its a mess and was probably locally impacted. And I don’t understand the logic in arguing managers should give up because climate change has had significant impacts on corals. I’ve said it a million times: local impacts need to be mitigated. We all agree on that. I think you’re underestimating managers and local conservation capacity. (All the managers I know acknowledge climate change but aren’t giving up). As the Ocean Optimism symposium highlighted over the  weekend, local successes are realistic and very much meaningful and worthwhile.
>>> 
>>> "and there is overwhelming evidence of land-based stress going back to the 70’s”
>>> 
>>> You have been promising this list-serv these references for years now. If you ever find them, please do share with us if you have the time.
>>> 
>>> "how well could coral reefs survive ocean warming if they were not already stressed by [local] human impacts?”
>>> 
>>> That experiment has been run dozens of times. On the northern GBR, on Scott Reef, off Southern Cuba or in the Bahamas, across the central Pacific, etc. The answer is not well at all.
>>> 
>>> The reason is that local impacts do not appear to act synergistically with ocean warming. As Cote and Darling suggested (http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1000438), the interaction appears to be antagonistic, not synergistic. Either that or the impact of warming is so much stronger that it swamps the local and synergistic signals. Also see Darling et al 2010: htt
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