World Weather Attribution
World Weather Attribution is an academic collaboration studying extreme event attribution, calculations of the impact of climate change on extreme meteorological events such as heat waves, droughts, and storms. When an extreme event occurs, the project computes the likelihood that the occurrence, intensity, and duration of the event was due to climate change. The project specializes in producing reports rapidly, while news of the event is still fresh. World Weather Attribution was founded in 2014 by climatologists Friederike Otto, who continues as leader, and Geert Jan van Oldenborgh. Participating institutions are Imperial College London, the Royal Netherlands Meteorological Institute, Laboratoire des sciences du climat et de l'environnement, Princeton University, the U.S. National Center for Atmospheric Research, ETH Zurich, IIT Delhi, and climate impact specialists at the Red Cross / Red Crescent Climate Centre. The WWA response to an extreme meteorological event has three parts: Define the event: the geographic region affected, which weather parameters are of interest. Gather historical data: weather data from the region from 1950 to the present. From this historical data statistics on normal and extreme weather patterns for the locale can be computed. Simulate the event many times with computer models, comparing simulations with present-day greenhouse