An eye-opening year of extreme weather and climate

From the persistent droughts of southern Africa and Central America in the early part of the year to the more recent devastating extreme rainfall in Spain and the deadly Hurricane Helene along America’s east coast, 2024 has been a year of climate events that affected the lives of billions of people.

In a recent paper published in Advances in Atmospheric Sciences, an international team of scientists led by Dr Wenxia Zhang at the Institute of Atmospheric Physics, Chinese Academy of Sciences, provide an overview of the characteristics and impacts of the most notable extreme events of the year, including rainfall and flooding, tropical cyclones, and droughts. Moreover, they discuss their causes, the role of global warming, and the challenges we face in the future to be “climate-resilient”. Dr Zhang and her team have been conducting an annual review of the global climate extremes since 2022, and this year they found it to be marked by exceptional rainfall and flooding.

“Most extreme events have a large random element in that they are subject to fluctuations in the weather, and occur when weather patterns set up in just the 'right' way.  Some extremes are more likely when larger-scale drivers such as ENSO influence the weather patterns in a region,” says Dr James Risbey at CSIRO, coauthor of the study.

In particular, many of the extreme rainfall and drought events of 2024 were related to the atmospheric configurations associated with the El Niño in winter 2023/24. However, ENSO does not fully explain individual events. Layered on top of that, according to studies of extreme event attribution, or “attribution science”, we know that human-induced climate change since the pre-industrial era has in many cases exacerbated extreme rainfall, tropical cyclones, and droughts, and therefore their associated socioeconomic impacts.

“The climate change influence can be direct through physical processes causing the extreme, or indirect in influencing the weather, large scale drivers, and key baselines,” adds Dr Risbey.

“This is consistent with basic physical understanding that anthropogenic warming leads to increases in atmospheric moisture and evaporative demand, and hence, potentially enhances extreme rainfall and droughts, respectively”, explains Dr Wenxia Zhang.

Despite our understanding of why the world is experiencing increasingly strong and frequent extreme climate events, the research team behind this study make it clear that key challenges remain in our knowledge and attribution of these phenomena—not least the often seen inconsistencies between observed and modeled extremes (especially for extreme rainfall), which limits our confidence in attribution results.

“Improved extreme event attribution requires better understanding of climate change”, says Dr Micheal Brody of George Mason University (USA) and the International Agricultural University (Uzbekistan), another of the paper’s authors. “More accurate attribution of extreme events is expected to inform decision-making, ranging from post-disaster recovery to future preparedness”.

Another crucial angle to this annually developing story of our climate is our ability to accurately forecast and broadcast the occurrence of extreme events, and then to act appropriately. Doing so could save many of the lives of the people that otherwise fall victim to the floods and hurricanes like those seen in 2024.

“Some of the extreme events witnessed in 2024, such as Hurricane Helene, were well forecasted”, notes Dr Zhuo Wang from the University of Illinois, another member of the team. “The destructive impacts were partly due to the vulnerability of the underprepared community to a changing climate”.

Dr Piotr Wolski, University of Cape Town, adds: “Increasing the quality of forecasts is important, but to reduce the impacts of extreme events, it is more important to achieve proper dissemination of warnings and to act upon them to lessen existing vulnerabilities”.

Dr Wolski's comments refer to the idea of being “climate-resilient”, which is fast becoming a crucial aspect in our holistic approach to climate change and the effects it is having on our society. As we shift to a feeling of almost inevitability that this is our world now, there is a rising sense of what can be done to protect ourselves alongside how to prevent the problem in the first place.

As we saw in Valencia, Spain, following the devastating floods and mudslides there in October, it does not take much for the impacts of extreme climate events to manifest as frustration and anger among the people affected.

Clearly, it is more urgent than ever to not only work towards better understanding the drivers of extreme weather and climate, but also to better predict their occurrence and develop effective systems to rapidly act upon the information at hand.

Only then can we be better prepared  for years like 2024.

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