Geoengineering Model Intercomparison Project (GeoMIP) Progress Report and Future Plans

Initial climate model simulations to test various proposed solar radiation management schemes, specifically creation of a stratospheric aerosol cloud to emulate volcanic eruptions or marine cloud brightening, chose a variety of global warming scenarios and insolation reduction targets, making them hard to compare and evaluate. Therefore, the Geoengineering Model Intercomparison Project (GeoMIP) was started in 2011 to organize standard experiments with the climate models run as part of the Coupled Model Intercomparison Project 5 (CMIP5) using identical global warming and geoengineering scenarios, to investigate the potential benefits and risks of the schemes. Hydrological cycle and ozone changes, regional climate responses, and impacts on agriculture and natural ecosystems are some of the issues addressed in analyses of the experiments. So far, 20 different climate modeling groups have run GeoMIP experiments and there have been 84 peer-reviewed GeoMIP publications, most of which are in the special sections of Journal of Geophysical Research – Atmospheres and Atmospheric Chemistry and Physics / Geoscientific Model Development. All the model output from the GeoMIP experiments is available on Earth System Grid, and we encourage colleagues to analyze these results and address additional scientific issues that have not yet been studied. GeoMIP is a CMIP Coordinated Experiment, as part of CMIP5, and is a CMIP6-endorsed MIP. There have been three rounds of proposed GeoMIP experiments. The first four involved global insolation reduction by turning down the Sun or injection of SO₂ into the tropical stratosphere. The second set included marine cloud brightening. The third set, global insolation reduction with various goals as well as cirrus thinning, which we call GeoMIP6, to have the same naming convention as CMIP6, are now being carried out by CMIP6 models, but all the past experiments remain open for new participants. There have been nine annual GeoMIP workshops in the U.S., the U.K., France, Germany, Norway, and China to organize experiments, coordinate analysis of the experiments, and plan new simulations, and the tenth one will be in Maine in the summer of 2020. We invite new participants to conduct simulations and join us in analyzing the results.