Excerpt:
Climate scenarios are fundamental to climate research and policy. For more than a decade, one scenario dominated research informing discussions of climate among scientists and decision makers. Called RCP8.5, today that scenario is widely recognized as implausible, leading to apocalyptic portrayals of future climate change and providing an unreliable basis for policy analyses for adaptation and mitigation.1
Remarkably, the climate science community appears to be on the brink of repeating the folly of RCP8.5, with a new extreme scenario that will be used in “thousands of research papers” and serve as the “foundation of major parts of IPCC assessments.”2 As was the case with RCP8.5, the new family of climate scenarios will be released with absolutely no formal evaluation of their plausibility or feasibility.
This is simply scientific malpractice for a field justified by its relevance to policy.
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The new scenarios — scheduled to be released in the coming weeks or months — have been created with no apparent evaluation of their plausibility. The failure to take plausibility seriously was behind the RCP8.5 debacle, as Justin Ritchie and I explained in depth in our analysis of how RCP8.5 came to dominate climate research and policy. RCP8.5 was never plausible and never should have been the focus of climate research, much less.
