How we know if extreme weather is due to climate change: ‘Event Attribution’
- ‘Event attribution’ works out what percentage, if any, climate change is responsible for the frequency and scale of extreme weather and other events such as extreme forest fires, melting glaciers, and rapid phenological shifts (plants and animals moving and/or dying out), drought (Fig. 1), and events such as the June 2021 Pacific Northwest heatwave that killed an estimated billion marine animals and over 500 people (US and Canada).
- If we understand how likely an event occurs because of climate change, versus the internal ‘noise’ of Earth’s climate—natural fluctuations such as El Niño—we can better plan for and help mitigate future climate costs.
- Insurance underwriters use these tools to help calculate how much you will have to pay for insurance, or to decline insurance; for example if you live in an area at risk from rising sea levels.
For too long, weather’s randomness has kept events such as these from being blamed squarely on climate change… Now, we can specify increased chances for specific events. This extends to forecasts: we can identify the places that are more likely to see wildfires, mudslides and fish die-offs. Such calculations dent both climate denial and a false sense of security. They take away the argument that ‘extreme weather happens anyway, so we don’t need to worry about it’. Extreme weather happens—and these metrics pinpoint what is becoming more likely, by how much and why… Such evidence is also useful for legal proceedings when citizens call corporations or governments to account for their role in climate change.“ – Richard A. Betts
As this is such a diverse field, if you would like to know more about specific events see World Weather Attribution.
Carbon Brief also regularly archives ‘science explainer’ event-attribution articles, including research on New Zealand’s vanishing glaciers. and patterns of extreme rainfall and drought (Fig. 3).
“More than 300 peer-reviewed studies have been published since 2000, that examine weather extremes around the world, from wildfires in Alaska (pdf) and hurricanes in the Caribbean to flooding in France and heatwaves in China. The result is mounting evidence that human activity is raising the risk of some types of extreme weather, especially those linked to heat.” – Carbon Brief
References and further reading
- National Science Challenges
- World Weather Attribution
- 2021: Philip et al; Rapid attribution analysis of the extraordinary heatwave on the Pacific Coast of the US and Canada June 2021. World Weather Attribution
- McSweeny; Pacific north-west heatwave shows climate is heading into ‘uncharted territory’ Carbon Brief analysis and interviews with the above researchers.
- 2021: Stone et al; The question of life, the universe and event attribution, Nature Climate Change 11 pp276–78
- 2021: Explaining Extreme Events from a Climate Perspective; Special supplement to the Bulletin of the American Meteorological Association (open access)
- 2020: Frame et al; Climate change attribution and the economic costs of extreme weather events: a study on damages from extreme rainfall and drought, (NZ) Climate Change 162, pp 781-797
- 2020: Betts; Heed blame for extreme weather, Nature article 26 Jan (open access)
- 2020: Raymond et al; Understanding and managing connected extreme events, Nature Climate Change, 10, pp611–621
- NZ Ministry for the Environment: Environmental Reporting – New Zealand Extreme weather events
- Carbon Brief: Extreme weather attribution Nature Climate Change 10 pp726–731
- 2020: Bonfils et al; Human influence on joint changes in temperature, rainfall and continental aridity Nature Climate Change 10 pp726–731
- 2020: Vargo et al; Anthropogenic warming forces extreme annual glacier mass loss Nature Climate Change
- 2020: Ortega; Unusual Arctic warming explained by overlooked greenhouse gases, Science
- 2020: Smith; The unexpected link between the ozone hole and arctic amplification The Conversation