[Coral-List] Call to action re New paper on coral bleaching in Science

Peter Sale sale at uwindsor.ca
Thu Jan 11 16:16:12 EST 2018

The recent paper in Science by Terry Hughes et al (Science 359: 80-83), documenting the increasing frequency of bleaching of coral reefs, reports a trend to diminishing return-time for bleaching events that will be devastating for coral reef systems.  The global mean return-time is now ~6 years.  These data amply support a hypothesis put forward by Simon Donner et al (2005, Global Change Biol 11: 2251-2265) that return-time will continue to diminish and could be less than 2 years for the great majority of reefs by 2035 or so.  The "call to action" placed on this list by Sarah Frias-Torres, on reading the Hughes paper, is justified.

The imminent demise of coral reefs as we know them provides the reef science community with a powerful weapon for the battle to convince the global community that the need to deal with climate change is critical.  The empirical evidence is abundant that coral reefs have already sustained substantial damage from human impacts, and that the damage caused by climate change has reached a level that exceeds the regenerative capacity of reefs.  But do we have the capacity to use this weapon effectively to sway the minds of others?

I suggest it is fully appropriate for the reef community to continue our internal, critical discussions of relative merits of alternative management strategies, including coral gardening/restoration, parrotfish protection, selection and/or genomic techniques to identify and propagate heat-tolerant strains of corals or their symbionts, and even simply the fully effective management of MPAs.  We need to critique what is being proposed or discovered..  We need to be humble in touting our own discoveries or achievements because none of us has yet found the magic bullet that is going to save coral reefs.  We need this discussion if we are to develop the more effective local management that is needed.  At the same time, we need a public discussion that conveys a coherent consensus message from our community to the world.

I suggest that public message could be built around the following 6 points:

  *   Coral reefs are important ecologically, economically, culturally; and they sustain the lives of a significant proportion of people on this planet;
  *   Coral reefs are deteriorating globally at a rapid, and increasing rate due to several human impacts; of these, coral bleaching, caused by ocean warming, itself a consequence of our releases of GHGs to the atmosphere, is now a major factor, and the frequency of bleaching events causes damage that already exceeds the regenerative capacity of reef systems;
  *   The pace of deterioration is such that the future condition of reefs, and the ecosystem services they provide to people, is now critically dependent on the effectiveness of global GHG emissions reduction;
  *   The future that is likely under the most optimistic IPCC scenarios (i..e. +2o or +1.5oC above preindustrial) looks marginal for coral reef systems, and current trajectories of GHG emissions are woefully inadequate if we want coral reefs on this planet beyond mid-century;
  *   On the other hand, with aggressive GHG emissions abatement, coupled with vigorous management of reef systems to address our other negative impacts, we could achieve a post-2050 world with viable reef ecosystems continuing to provide the important ecosystem services they now provide;
  *   Coral reefs are not alone; while the impacts of climate change on reefs are already both extreme and starkly clear, reefs provide an early glimpse of the danger we are causing to this planet's biosphere through our careless dumping of GHGs into the atmosphere.
Peter Sale
University of Windsor

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