Exploring extreme heat wave events

The summer of 2022 brought extreme heat over most of the Eurasian continent and North America. This abnormal warming led to extraordinarily long-lasting extreme heat waves.

A research team from the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences has reviewed the extreme heat wave events of this summer as well as the progress in related studies in recent years, and discussed possible future directions for high temperature study.

The commentary article was published in Atmospheric and Oceanic Science Letters on Oct. 17.

The heat waves that occurred during the summer of 2022 had far-reaching impact. The extreme temperatures were accompanied by droughts that severely affected Europe and the Yangtze River basin in China. These droughts affected hydro power and led to power shortages in some areas. The extremely high temperatures and severe drought also contributed to massive wildfires in Europe, North America, and Asia.

Scientists attribute the heat wave and drought in the Yangtze River basin to unusual atmospheric circulations. "However, the reason for the long-lasting extraordinary atmospheric circulations in summer 2022 is an interesting scientific issue and requires investigation," said LU Riyu, a researcher from IAP. In addition to the unusual atmospheric circulations, climate change is also a contributing factor for heat waves.

For humans, prolonged exposure to heat waves can lead to illnesses such as heat cramp, heat exhaustion, and heat stroke. The heat waves also make humans more vulnerable to cardiovascular and respiratory diseases.

The extreme heat also has a negative impact on the environment. High temperatures decrease photosynthesis and increase vegetation respiration, which causes a reduction in the amount of carbon stored in ecosystems. Heat waves increase wildfires, further contributing to carbon emission in ecosystems.

Various issues regarding heat waves remain to be further investigated. These issues include, but are not limited to, the mechanism responsible for formation of heat waves, the impacts of extreme heat on human health and terrestrial ecosystems, and extreme heat in sparsely populated areas of the world.

"Heat waves will occur more and more frequently under global warming, and some of them are expected to be unprecedented like those in summer 2022. Therefore, a better understanding of heat waves and their impacts is urgent and necessary," said LU.