Extreme event attribution, also known as attribution science, is a relatively new field of study in meteorology and climate science that tries to measure how ongoing climate change directly affects recent extreme weather events.
Attribution science was first mentioned in a 2011 "State of the Climate" published by the American Meteorological Society which stated that climate change is linked to six extreme weather events that were studied. While extreme weather events have occurred in the past, attribution science aims to determine which such recent events can be explained by or linked to a warming atmosphere and are not simply due to natural variations. German climatologist Friederike Otto further explained that attribution science aims to answer the question, "did climate change play a role" in specific extreme events "within the news time frame—so within two weeks of the event".
Attribution studies generally proceed in four steps: (1) measuring the magnitude and frequency of a given event based on observed data, (2) running computer models to compare with and verify observation data, (3) running the same models on a baseline "Earth" with no climate change, and (4) using statistics to analyze the differences between the second and third steps, thereby measuring the direct effect of climate change on the studied event.
Heatwaves are the easiest weather events to attribute. Climate change can affect the intensity and frequency of extreme weather differently, for example the 2010 Russia heat wave was made far more likely but not more intense.
Attribution science may affect climate change litigation, perhaps by increasing lawsuits against companies for causing and governments for not addressing climate change.
A review summarized confidence, probabilities and costs-severities – such as economic costs, financial costs and number of early losses of life – of links to climate change and identified potential ways for the improvement of the field such as "improving the recording of extreme weather impacts around the world, improving the coverage of attribution studies across different events and regions, and using attribution studies to explore the contributions of both climate and non-climate drivers of impacts.".