Scores of scientists around the world study all sorts of phenomena related to climate change. Hurricane behavior, coral bleaching, impacts on human health, and jet stream patterns occupy the time of many climate researchers. Emerging from these specialties is a new field – the study of extreme weather events and why they came to be.
For about 20 years, curious scientists have been posing a specific question about big weather events: Would an extreme event have happened without the influence of human activity?
This filtering for human fingerprints has given rise to “attribution science,” also known as extreme event attribution. The field melds meteorology and climate science, harnessing models and historical observations to determine whether recent events are due to more than just natural variation.
Extreme Weather and the Smoker
Stephanie Herring, a U.S. scientist and strong voice in the field, puts attribution science into perspective:
“One of the most common methods to calculate the change in risk of an event due to human-caused climate change is to employ a statistical approach originally developed in public health called the fraction of attributable risk (FAR). On public health, for example, this would be used to assess how smoking increases your chances of lung cancer. By comparing cancer risk in a cohort of patients who smoke to cancer rates in a control group of nonsmokers, researchers can determine how much smoking increases the risk of lung cancer.”
In translation, did smoking (human activity) set the stage for that cancer (epic flood, heatwave, typhoon, cold spell, etc.)? Had it not been for humans warming the planet, would that extreme event have happened?
Herring and co-editors publish a set of studies each year for the Bulletin of the American Meteorological Society analyzing extreme weather events. Recently, one study found South Korea’s average temperature during October 2021 was almost 7°F higher than the average observed between 1991-2020, which corresponds to a one-in-6,250-year event. The climate model used in the study projected that this kind of heatwave could become commonplace in South Korea by 2060 without ambitious cuts to greenhouse gas emissions.
In 11 editions, more than 80 percent of the 200+ research findings in the publication series have identified a substantial link between an extreme event and climate change. In fact, researchers are concerned that they may be underestimating future risk.
The study of extremes has led to the founding of World Weather Attribution, an academic collaboration and the development of an attribution map of past events hosted by Carbon Brief.
Extreme Weather: The Human and Financial Realities
The toll of extreme events is demonstrated by:
- The human cost: In 2022, 3.4 million Americans were displaced from their homes by extreme weather.
- The financial loss: A cumulative $2.475 trillion in U.S. damages has been sustained between 1980-2022 because of weather disasters.
In April 2023, U.S. scientists presented a federal report on extreme weather risk. Its authors advocate for creating a better measure of risk and a means to produce climate forecasts, along the same lines as weather forecasts. Advances in observations, modeling, and computation now make it possible to create more accurate and operational assessments of risk.
Unfortunately, many regions around the world that are at risk from climate change are also home to many disadvantaged communities. Assessing what has happened and applying it to our future takes on even greater importance.
[1] FAQ 11.2 Figure 1 in IPCC, 2021: Chapter 11. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Seneviratne, S.I., X. Zhang, M. Adnan, W. Badi, C. Dereczynski, A. Di Luca, S. Ghosh, I. Iskandar, J. Kossin, S. Lewis, F. Otto, I. Pinto, M. Satoh, S.M. Vicente-Serrano, M. Wehner, and B. Zhou, 2021: Weather and Climate Extreme Events in a Changing Climate. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1513–1766, doi: 10.1017/9781009157896.013.]
