One study suggests that climate change is causing the extreme temperatures in Canada
The extreme heat wave in western Canada and the USA has set new record temperatures there. Hundreds of premature deaths are attributed to the heat. A new scientific study now shows that the new extreme values are very likely to be due to climate change. Global warming made the heat wave at least 150 times more likely, according to the research team.
In the community of Lytton in British Columbia, Canada, the thermometer had risen to almost 50 degrees Celsius – 49.6 degrees to be precise – last week, a new record for Canada. Then a forest fire raced over Lytton. The entire town center burned down, around 100 people had to flee. Large US cities such as Seattle and Portland also recorded record temperatures.
According to the analysis of the “World Weather Attribution” initiative, the heat wave would have been almost impossible without man-made global warming. The team is an association of international scientists who analyze the role of climate change in extreme weather events. To do this, they compare the observed weather data with a climate model world without increased greenhouse gas concentrations. 27 researchers from Canada, the USA, Germany, the Netherlands, Switzerland, France and Great Britain participated in the current study. In previous studies, the network has already identified links between climate change and extreme weather events, including the 2018 and 2019 European heatwaves, the 2019-20 Australian forest fires, the tropical storm Imelda that struck Texas in 2019, and the 2020 Siberian heatwave.
According to the study, there are two possible explanations for the extreme temperatures during the heatwave in Canada and the USA: First, climate change made the heatwave more likely, but it remains an extremely unusual event. According to this, great drought and special atmospheric circulation conditions – a so-called “heat dome” – together with climate change would have led to the unusually high temperatures.
Second, the climate system has exceeded a threshold at which even a slight further increase in global mean temperature causes a faster rise in extreme temperatures than expected. This would mean that record heatwaves like the most recent one are already more likely than the climate models predict so far. The team describes the heat event in North America as a “clear warning” that extreme temperatures can also occur up to latitude 50 degrees north – this would affect almost the entire USA and France as well as parts of Germany, China and Japan.
The climate researcher Friederike Otto commented: “What we are experiencing here is unprecedented. It is not normal to break temperature records by four or five degrees Celsius. ”The event in Canada and the USA is extraordinary. It can no longer be ruled out that heat extremes will already occur today, “which we would only have expected with further advanced global warming”. Otto is a member of the research group and director of the Environmental Change Institute at Oxford University.
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