Chinese and foreign scientists: new characteristics of global extreme weather and climate events, such as the early occurrence time and compounding

The frequent occurrence of weather and climate events such as extreme heat waves around the world in 2023 is still fresh in the memory and has attracted the attention of atmospheric scientists. Based on the continuous research and analysis, Chinese and foreign scientists jointly wrote an article in the professional academic journal Advances in Atmospheric Science published on April 17, reminding that new characteristics such as advanced time and compounding of extreme weather and climate events are emerging around the world.

Led by the Institute of Atmospheric Physics (Institute of Atmospheric Sciences) of the Chinese Academy of Sciences and jointly with the British Meteorological Office, the Sorbonne University of France, the Max Planck Institute of Meteorology in Germany, the Argentine Institute of Glaciology and Environmental Sciences, and the Shanghai Typhoon Research Institute of the China Meteorological Administration, the Institute of Atmospheric Sciences published an article in the latest issue of "Advances in Atmospheric Science" in the "News and Opinions" column, on the basic facts of the world's major extreme events in 2023. Impacts and key physical processes are reviewed and summarized, and the role of internal climate variability and anthropogenic climate change is further understood through a complete perspective of past to future changes.

According to the World Meteorological Organization, 2023 was the hottest year since 1850, with the observed global average temperature being 1.45°C ± 0.12°C warmer than pre-industrial (1850-1900). Along with record-breaking high temperatures, 2023 has seen frequent extreme weather and climate events around the world, including heat waves, extreme precipitation, sudden changes in drought and floods, wildfires, sandstorms, etc. The latest publication focuses on the many new features that are emerging from these extreme events:

First, extreme heat events occur earlier. Second, the simultaneous occurrence of heat events in multiple places is increasing, and such spatial compound heat waves may occur in multiple food producing areas at the same time, thus posing a threat to global food security. Third, for extreme precipitation, the intensity of extreme precipitation is greatly exacerbated by the strong water vapor transport brought by strong cyclones. Fourth, with regard to drought, some areas are still experiencing multi-year drought, while others are experiencing a transition from multi-year drought to flooding. Fifth, the outbreak of large-scale wildfires and sandstorms has increased the interaction between extreme events and ecosystems.

Zhang Wenxia, the first author of the article and an associate researcher at the Institute of Atmospheric Sciences of the Chinese Academy of Sciences, said that these increasingly increasing and intensifying extreme weather and climate events have been listed as the world's top risks in the next decade by the World Economic Forum's latest Global Risks Report. In order to deal with extreme climate change more effectively, it is necessary to pay attention not only to its intensifying trend, but also to the emerging new characteristics of extreme events, which pose new challenges to the study of extreme events.

Co-author Robin Clark, a senior researcher at the UK Met Office, points out that one of the new features of extreme events is the seasonal variation of extreme events, which are now likely to occur in seasons that are unlikely to occur in the past.

Chinese and foreign scientists also pointed out that the compound characteristics of extreme events, including the rapid turn of drought and flood, also need to be paid attention to, and they often have a greater impact than the occurrence of extreme events alone. In addition, the interaction between extreme weather and ecosystems is increasing through large-scale wildfires and other events in warm and dry climates, and the carbon emissions generated by wildfires and their damage to natural carbon sinks are issues that cannot be ignored in achieving the global carbon neutrality goal, which pose new challenges to the study of extreme events.

They stressed that in addition to raising scientific awareness, an effective response to extreme events requires early warning, which is the goal of the United Nations' Early Warning for All Initiative, launched in 2022, to achieve universal access to early weather warning systems for all by the end of 2027 in response to increasingly extreme weather and climate change.

"This will require the joint efforts of the international community, in particular to strengthen collaboration in the Global North and the Global South. Dr. Li Chao, co-author of the article and the Max Planck Institute for Meteorology in Germany, said.