
==== Front
iScience
iScience
iScience
2589-0042
Elsevier

S2589-0042(24)02030-3
10.1016/j.isci.2024.110805
110805
Backstory
Compound events in the coupled climate and socio-ecological system
Zscheischler Jakob jakob.zscheischler@ufz.de
12∗
1 Department of Compound Environmental Risks, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
2 Department of Hydro Sciences, TUD Dresden University of Technology, Dresden, Germany
∗ Corresponding author jakob.zscheischler@ufz.de
05 9 2024
20 9 2024
05 9 2024
27 9 110805© 2024 The Author(s)
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).
The most devastating climate-related impacts are typically a result of multiple compounding drivers among the atmospheric and socio-economic domain. Originally promoted by the climate sciences, compound event research extends to more and more disciplines, thereby turning into a truly interdisciplinary field. This is well reflected in the special issue “compounding effects as drivers of extreme events in socio-ecological systems”.
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pmc Bridging the different fields and finding a common language and analytical tools to study compound events is a great opportunity to learn from each other, develop new concepts and tools, and thereby create synergies.

Developing this new topic into a mature field of research with its own research questions and tools will be the task of this new generation of scientists.

Above image: Large and damaging wildfires are an example of a compound event, where multiple meteorological drivers (drought, high temperatures, and strong winds) frequently interact with socio-economic drivers (human ignition and forest management). Particularly widespread wildfires can challenge the organization of emergency response. This image shows the 2022 wildfire in the Saxon Switzerland National Park in eastern Germany, one of the most severe in history in that region, and a firefighting helicopter trying to contain the fire. Photo: André Künzelmann/UFZ.

Introduction

As part of the 50th anniversary of Cell Press in 2024, we are celebrating “science that inspires” and exploring the real-world impact of our science in meeting society’s greatest challenges. These complex challenges require interdisciplinary solutions and collaborative efforts. At iScience, we aim to promote and highlight this approach to scientific discovery, sharing stories focused on interdisciplinary research that stimulate discussion and celebrate the expanding diversity in scientific research. This backstory is part of a series highlighting exciting researchers working in the fields of life, health, physical, earth, and environmental and social sciences who inspire with their interdisciplinary thinking while they work to meet society’s greatest challenges.

First impressions

What are compound weather events?

Compound events are events where multiple drivers join forces to cause potentially large impacts. Overcoming the dominant focus on univariate climate extremes and their limited relevance for climate impacts,1 the concept has led to a flurry of research primarily in the climate sciences, with the development of new analytical tools and the study of many different event types.2,3 However, “compounding” can also occur between climatic and non-climatic drivers, which is been more and more recognized recently4,5 and is also a focus in the special issue on “compounding effects as drivers of extreme events in socio-ecological systems”.

Motivation

What are the most important and exciting questions in the field, and why do they matter?

Better understanding what drives large climate-related impacts is an exciting research question, as it helps us to make better predictions on climate risks in the future and thereby inform on adaptation options. Quantifying the dependencies between multiple impact drivers is very important in this context, as these dependencies determine how likely such an event is to happen.6 Another relevant question is how well climate models represent high-impact drivers, and whether impact models correctly map from multivariate climate conditions to impacts. This is because, ultimately, these are the models that we use to make predictions about possible future events and impacts.

Interdisciplinary science

What role does interdisciplinarity play in the context of compound weather events?

Compound event research is a truly interdisciplinary field, bringing together climate science, statistics and machine learning, and various impact domains such as hydrology, engineering, agriculture, and ecology. It has been brought far by the European COST Action DAMOCLES, which created a new network of scientists from these different fields (https://www.cost.eu/actions/CA17109/). Different domains might face very similar challenges when it comes to understanding climate impacts, and an exchange of ideas can be extremely fruitful. For instance, considering compounding drivers in the disaster risk reduction cycle may improve risk management in many different domains.7 In this context, iScience is a great venue for compound event research, as traditionally journals are highly disciplinary, which limits the visibility of the interdisciplinary research and the chances to connect with each other across disciplinary boundaries.

Challenges and opportunities

What are the greatest challenges the field is facing?

Identifying compounding drivers of large impacts is a challenging question, because every event is unique. It is thus very difficult to generalize insights from individual events, and pooling events to allow for robust statistical analyses needs to be done carefully. Data on impacts is another challenge, as these data often only exist on very limited domains or regions. Bridging the different fields and finding a common language and analytical tools to study compound events is a great opportunity to learn from each other, develop new concepts and tools, and thereby create synergies.

Compound event research is a very young research area, which is also reflected by the researchers contributing to it, most of whom are early career researchers. Developing this new topic into a mature field of research with its own research questions and tools will be the task of this new generation of scientists.

Where do we go from now?

So far, most compound event research focused on compounding drivers in the climate system. However, drivers can also be linked with societal forces, such as governance, markets, and other decision-making structures, leading to dynamic vulnerability.8 Moreover, feedbacks between physical and socioeconomic drivers may exist. The geographic shifts of climate extremes and hydrological intensification due to climate change will lead to new types of weather events, and the resilience of systems that are typically adapted to past climate to such new event types remains unexplored. The interactions between climatic and non-climatic drivers in the occurrence of high-impact events are an important and highly relevant topic of future research.
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References

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2 Zscheischler J. Martius O. Westra S. Bevacqua E. Raymond C. Horton R.M. van den Hurk B. AghaKouchak A. Jézéquel A. Mahecha M.D. A typology of compound weather and climate events Nat. Rev. Earth Environ. 1 2020 333 347 10.1038/s43017-020-0060-z
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