Systematic review of the uncertainty of coral reef futures under climate change, datasets

Climate change impact syntheses, such as those by the Intergovernmental
Panel on Climate Change (IPCC), consistently assert that limiting global
warming to 1.5°C is unlikely to safeguard most of the world’s coral reefs.
This prognosis primarily stems from 'excess heat’ threshold models,
which assume that widespread coral bleaching predictably occurs when
temperatures accumulate beyond a specific threshold. Our systematic review
of research projecting coral reef futures to climate change (n=79)
revealed that 'excess heat' models constituted only one third
(32%) of all studies but attracted a high proportion (68%) of citations in
the field. We observed that most methods employed deterministic
cause-and-effect rules rather than probabilistic relationships, impeding
the field's ability to estimate uncertainties of coral reef futures.
In attempting to assess the consistency of projected impacts, we aimed to
identify common coral reef metrics under the same emissions scenarios.
However, disparate choices in metrics and emissions scenarios hindered a
cohesive synthesis and limited the exploratory analysis to a small
fraction of available studies. We found substantial discrepancies in
expected impacts to coral reefs, suggesting that some 'excess
heat' models may project more extreme impacts than other methods.
Drawing on lessons from the field of climate change science, we propose
that an IPCC ensemble-like approach to generating probabilistic
projections for coral reef futures is feasible. Successful implementation
will require improved coordination among modeling efforts to select common
output metrics and emission scenarios, addressing existing geographical
biases, among other gaps in current modeling efforts.