On June 29, 2021, a heat wave swept through western North America, setting a record temperature of 49.6 ℃ for Canada (4.6 ℃ higher than the previous peak), and led to the declaration of a state of emergency in California. According to a new study published in the journal progress of science by researchers from the University of Bristol on the 4th, this heat wave is one of the most extreme heat waves observed anywhere in the world since records. In the future, the heat wave will become stronger with the deterioration of climate.
The map shows the maximum extreme amplitude in each region since 1950, expressed as a deviation from the average temperature. Source: University of Bristol, UK
Heat wave refers to a long period of hot weather that may be accompanied by a climate of high humidity relative to the expected conditions of a certain area at a certain time of year. It is one of the most destructive extreme weather events. For the UK, the UK National heat wave threshold is reached when a site records that the daily maximum temperature for at least three consecutive days reaches or exceeds the heat wave temperature threshold.
Research shows that the heat wave in western North America in June 2021 was the deadliest weather event in Canada's history, killing hundreds of people. Wildfires caused by high temperature weather have caused large-scale infrastructure damage and crop losses.
The study also shows that there is a correlation between extreme heat waves and local temperature. The three hottest temperatures recorded previously were Southeast Asia (32.8 ℃) in April 1998, Brazil (36.5 ℃) in November 1985 and the southern United States (38.4 ℃) in July 1980.
Researchers say the global climate has been warming since the survey began in 1950. The team also used climate models to predict the trend of heat waves in the next century: the possibility of heat waves increases, and their intensity will rise with the rise of global temperatures.
Co participants in the study Professor Dan Mitchell, Professor of climate science at the University of Bristol, said: "climate change is one of the biggest global health problems of our time. However, we have found that many heat waves outside developed countries have attracted little attention. High temperatures cause national burden or thousands of deaths, and extreme high temperatures are most likely to have an impact on some countries that cannot adapt to climate change."
The researchers say that although the highest temperatures do not necessarily have the most serious effects, they are often related. Improving the understanding of extreme climate and its location will help to formulate targeted measures for the most vulnerable areas and effectively solve the negative effects of high temperature.