In 2007, the Intergovernmental Panel on Climate Change released its fourth assessment report based on a new group of climate models, the value of which earned the IPCC the Nobel Peace Prize. The new models—collectively referred to as CMIP3—revealed information about climate change that sealed the deal on a number of lingering questions: Is global temperature increasing? Yes. Is it caused by humans? Almost certainly. But one major question—perhaps the most important one of all—remained. What should we do about it?
To answer that question, stakeholders would need more locally relevant information on much shorter time scales. So when the next generation of climate models was released in 2012, scientists had high hopes. These models included more physical, chemical, and biological processes, often considered at a much finer-grain than the previous models. Surely CMIP5, as the new ensemble of models is called, would provide credible projections at the scales relevant to stakeholders.