[Coral-List] Thoughts on coral decline and the future.

[Risk, Michael]

   Hello Thomas.

   Thank  you  for your response. I have no answers, just a basketfull of
   concerns. I wonder if my grandchildren (3, so far) will ever see anything
   like the reefs that I have seen.

   I would question your assertion that global changes have already outstripped
   land-based stresses. Yes, we hear depressing stories of bleaching. Right
   now,  we  do  not know what the pace of recovery will be. We know that
   nutrients slow that recovery (Wooldridge and Done-great to see Terry still
   trucking along). Michael Schleyer, a good friend of mine and a top scientist
   working in difficult conditions, recently emailed me (Mike, hope quoting you
   is OK-too late now!) “I have had the good fortune of visiting remote reefs
   such as the Chagos, Glorieuses and Europa and, while they have all been
   whacked by bleaching, their recovery has been remarkable.” I would also
   direct  you  to his excellent new paper, Porter and Schleyer 2017 (DOI
   10.1007/s00338-016-1531-z.)  This  describes another set of reefs on a
   downward trajectory off the coast of South Africa-but in this case, the
   water temperature went down, not up. Mike tells me he had an awful time
   getting  this  accepted,  which  given  the mindset of many coral reef
   biologists, I do not doubt for a second.

   Another paper that had a difficult delivery is Tomascik et al. 1996 (Coral
   Reefs 15: 169). Briefly: a lava flow entered a bay in the Banda Islands, in
   eastern Indonesia, with much hissing and boiling. The locals now call that
   Hot Water Bay (Air Panas). Five years later, the lava flow had greater than
   60% coral cover, with tabulate corals almost a meter in diameter. Tom and
   his co-authors (Rob van Woesick and Tom’s wife, Anmarie Mah) had a heckuva
   time with this one, because there was great resistance to the idea that
   corals could grow so quickly in such a seriously overfished environment. The
   answer, of course, is that the water is dead clean, wonderfully clear-close
   to the best diving of my life.

   Before anyone tries to tell me of widespread death of Indo Pacific reefs
   from global change, I would like to be reassured that they had read Tom
   Tomascik’s work, and Evan Edinger’s, and had spent some time diving the
   beautiful (not) reefs next to Singapore, Hong Kong, Jakarta… You get the
   picture.

   Re dust: I am sure Gene can respond much better than I can. I think he has
   an  excellent  point,  and  I don’t for the life of me see why so many
   biologists  refuse to consider it. You are correct, it “works” for the
   Caribbean.  Previous Caribbean reefs must have faced input of dust and
   survived, but-the Sahara is growing, which means the rate of dust production
   is going up. And of course there are truly enormous dust storms that come
   off the Arabian Plate over into the Gulf.

   In short, no matter who “wins” this race, we won’t like the outcome.

   Continuing on this depressing vein: the sea level rise we are seeing now is
   almost at the limits of upward reef accumulation (read Dennis Hubbard’s
   stuff). This rate is basically the calm before the storm. Greenland has yet
   to destabilize, although there is meltwater running underneath the ice. Much
   of  the  land  ice  in  Antarctica continues to shrink, but not as yet
   catastrophically. The lesson of the past is that, during meltwater-driven
   transgressions, rises in sea level can be rapid and episodic. Remember that
   Nature paper my wife wrote (urk, 20 years ago) showing that the Gulf Stream
   started to shut down in less than 4 years. (My wife is no longer in science.
   She told me "there are a lot of nasty people there, and that may include
   you.")

   We really are entering into the unknown, and you are correct: the recent
   Syrian refugee problem will look like a flea bite. We need to do the best we
   can: set examples in our personal life, and be politically active. And hope.

   Mike

   On May 12, 2017, at 12:18 PM, [1]thomas at seamarc.com wrote:

   Dear Michael,
   Thanks for your effort in summing this up.
   I read: "There  is a large body of research supporting the contention that
   land-based stress dominated until late in the 20^th century, but global
   warming is gaining quickly in a race we would rather not watch." The lessons
   from coral reefs other than the Caribbean is that global has unfortunately
   already overtaken the land based stresses. Just like I suppose that the land
   based stresses would have overtaken the effects of the dust at some stage,
   making it a lesser concern.
   Regarding the dust, maybe Gene can tell us has significant the year 83 in
   geological terms. If ever such events have happened in the past, I guess the
   reefs would have recovered before 83. Why wouldn't the reef have recovered
   by now? If such events are more frequent than before, explaining a
   continuous decline, are we not talking about an early sign of climate
   change? We also need to mention that this is mostly a Caribbean problem as
   the dust transport mentioned represents 70 % of the dust movement over the
   earth.
   You also write: "Human populations will be displaced, perhaps suddenly, by
   unpredictable rises in sea level. The time may come when society as a whole
   may not have the resources to save coral reefs, because people come first".
   I am under the impression that the sea level rise is predicted, and even
   measured. The question however is, looking at the current situation, by how
   many times do we have to multiply the amount of Syrian refugees for the
   situation to become unbearable?
   Regards,
   Thomas
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References

   1. mailto:thomas at seamarc.com
   2. mailto:Coral-List at coral.aoml.noaa.gov