Have models become better at simulating the climate system since the most recent assessment report by the Intergovermental Panel on Climate Change (IPCC), published in 2007? That depends, said authors of research recently published in Nature Climate Change.
With the latest IPCC report (AR5) revving up, scientists have been analyzing the newest generation of models, which have nearly twice as more grid cells and incorporate more advanced understandings of the climate system compared to the previous generation of models used in the 2007 AR4 report. These improvements have helped substantiate some previous conclusions. For example, the general patterns of temperature and precipitation are similar, and the authors stated “this robustness across generations of models is positive… and provides strong support for the argument that climate change over the twenty-first century will probably exceed that observed over the past century.” However, comparisons of the agreement in the simulations of average precipitation in AR4 and AR5 models is nearly identical, suggesting the latest models have made few advances in precipitation projections in many regions.
This paper is one of the first of what likely will be many studies that compare previous results to newly minted ones. Early indications confirm conventional wisdom—climate models perform well for some processes and in some places.