Dear EarthTalk:

What is so-called attribution science and how does it relate to climate change?

William C., New York, NY

Attribution science is a rapidly evolving field that aims to understand the link between human activities and extreme weather. By discerning the extent to which climate change affects the frequency and intensity of these events, attribution science plays a crucial role in climate research. Understanding this relationship is essential for developing effective climate policies and enhancing global resilience to climate impacts.

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Attribution science seeks to quantify the influence of climate change on specific weather events. It involves the use of sophisticated computer models and extensive data analysis to compare current climatic conditions with hypothetical scenarios devoid of human-induced changes. The primary objective is to determine how climate change alters the probability and severity of extreme weather events. Key terms in this field include: climate, which refers to long-term atmospheric conditions; climate change, indicating significant changes in these conditions over time; computer models, which simulate climate behavior under various scenarios; and data, which provide the empirical basis for these simulations.

There are two main types of attribution science: event attribution and source attribution. Event attribution focuses on how climate change affects specific extreme weather events. For instance, human-caused climate change significantly increased the likelihood of the 2019 European heatwave and made the 2018 South African drought three times more likely. Moreover, climate change increased the rainfall during Hurricane Harvey by at least 15 percent and nearly doubled the area burned by wildfires in Western US forests. Meanwhile, source attribution identifies the pollutants and activities contributing to climate change. It involves measuring atmospheric concentrations, analyzing emissions data, and conducting modeling studies to pinpoint specific sources of greenhouse gasses.

Attribution science has roots in the 1990s and has advanced considerably with the development of more sophisticated computer models and statistical methods. These advancements have enhanced its accuracy and reliability, allowing for more precise connections between human activity and climate-related events.

The methodology involves comparing real-world data with counterfactual models—simulations of the world withouthuman-induced climate change. High-quality observational data is crucial for these comparisons, but there are challenges, particularly in data-scarce regions like developing countries. Future research aims to develop new methods suitable for such regions with limited data, examine regional impacts, and quantify slow-onset phenomena like sea level rise. These advancements will enhance our understanding of climate impacts and inform more effective adaptation strategies. Attribution science is crucial for shaping climate policies and strategies. Communicating the links between specific weather events and climate change raises public awareness and influences real-time decisions. Insights from attribution studies help communities build resilience against future climate risks.

CONTACTS

• From Research to Action: The Growing Impact of Attribution Science, https://blog.ucsusa.org/delta-merner/from-research-to-action-the-growing-impact-of-attribution-science/
• How do scientists know how much climate change affects a hurricane, a heat wave, a drought, and more? https://yaleclimateconnections.org/2024/05/how-do-scientists-know-how-much-climate-change-affects-a-hurricane-a-heat-wave-a-drought-and-more/

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