Many devastating extremes in 2023 were amplified by global warming

Destruction after hurricane
Destruction after hurricane
2023 was an extraordinary year for climate: each month from June onward was warmer than the corresponding month in any previous year. In this last half year temperatures exceeded 1.5C above pre-industrial levels (1850-1900), with some days even exceeding 2.0C. Throughout the year, extreme weather hit nations around the world including heatwaves, droughts, floods and wildfires. In the aftermath of those events, many people asked how those extremes related to the record warmth?

Record temperatures increases intensity

Studies from XAIDA, a consortium of leading European climate institutes, show that these record temperatures strongly increased the intensity of heatwaves, droughts and extreme rainfall. New Artificial Intelligence (AI) methods as deep neural networks, together with massive climate datasets, are enabling scientists to study the relationship between climate change and extreme weather in novel ways. "For more than ten years, attribution studies have shown that climate change is making several types of extreme weather events more intense. Now, with these new tools, we can study the underlying processes as well as the societal impacts in new ways’’, says VU Amsterdam Professor in Climate Extremes and Societal Risk, Dim Coumou.

Storms Otis and Daniel

In 2023 hurricane Otis killed more than fifty people and caused more than $US10 billion in damages. This made it one of the costliest tropical cyclones ever recorded in Mexico. Storm Daniel led to the collapse of three dams and the deaths of more than 3400 people. For both storms climate change had an important impact on rainfall. A warmer atmosphere can hold more water vapor, leading to heavier downpours. In addition, climate change can affect the dynamical processes within storm systems, which can further increase the amount of rainfall. A study by World Weather Attribution even found that climate change made the rainfall at storm Daniel up to 50% more intense. Throughout 2023, extreme weather events demonstrated how poorly prepared the world is for the growing risks of climate change.

Heatwaves around the globe

In July 2023, heatwaves hit the United States, southern Europe and China, with temperatures in the US and China exceeding 50C. Such heatwaves can be deadly and are also possible in Europe. The researchers found that heat waves much warmer than presently observed are possible. Heat stress associated with such worst-case heat waves present risks for large public events in cities. For example the upcoming 2024 Olympic Games in Paris, which are organised at the height of the summer season.
The studies have shown that heat waves over Europe are increasing faster than elsewhere due to dynamical changes in the jet stream. It is currently unclear why state-of-the-art climate models fail to accurately capture this trend, raising concerns about future projections of heat waves over Europe.

Drought, crop losses and wildfire

A recent XAIDA study shows that crop losses due to heatwaves and droughts, have been increasing since 1982 throughout important food-producing breadbasket regions in the Northern Hemisphere. It is worrying that there can already be seen in observations of the last 40 years, that crop losses due to hydroclimatic extremes are getting more severe. Agricultural drought also intensifies with climate change as warmer air dries the soils more rapidly. The long-lasting agricultural drought (2020-2023) in West Asia was the second worst on record, but in the current climate it is now a relatively common event expected to occur about once every decade. Warming also increased the risk of hot and dry conditions that fuels wildfire, like the severe wildfires in Canada in 2023.

Loss & Damage fund

The large number of devastating extremes in 2023, and the strong role of human-caused climate change on many of those stresses the need for adaptation of societies around the world. In vulnerable developing countries, climate extremes can result in human catastrophes. At COP28, important steps were made on the establishment of a fund to support vulnerable developing countries in dealing with loss and damage arising from extremes and other climate impacts. The devastating extremes in 2023 highlight the importance of a prompt operation of this Loss & Damage fund.

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