The recent heat wave in the northwestern United States and Canada was “virtually impossible” without man-made global warming. who is writing an international group of scientists in a first rapid analysis, published on Wednesday. In the current climate, they estimate the probability that such an event will occur there once every thousand years. But it’s hard to quantify exactly, they add, because it was such a rare and disproportionate event. The analysis was initiated by World Weather Attribution, an organization that studies extreme weather events and the role of climate change in them.
The Earth is now on average 1.2 ° C warmer compared to the pre-industrial era. If the climate continues to warm to an average of 2 degrees Celsius, such a heat wave will occur every 5 to 10 years. At the rate at which humans are now releasing additional greenhouse gases into the atmosphere, that point will be reached in the 2040s.
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The heatwave peaked on June 29, when a temperature of 49.6 degrees Celsius was reached in the Canadian city of Lytton. That’s nearly five degrees warmer than the country’s previous heat record. The heat caused a drought, which resulted in numerous forest fires in the affected area. Lytton was almost completely reduced to ashes. At least 721 people have died from the heat and the fires that followed.
Very different future
The researchers focused their analysis on the Seattle-Portland-Vancouver area, which is home to more than 9 million people.
They warn that the rapid warming of the climate is in unexplored territory – in uncharted territory. With “significant impacts on health, well-being and life”. Humans will have to adapt much faster in order to prepare society for “a whole different future”. For example, by setting up heat plans and building houses and offices that are better suited to the heat. Ever increasing greenhouse gas emissions must also be reversed and reduced to zero as soon as possible.
That the heat wave has reached such high temperatures, climatologists totally surprised. That such a thing was possible was not in their predictions. In their analysis, they looked to see if they may have overlooked a factor in the climate system that could explain the extraordinarily high temperatures. Based on current data, they do not believe this to be the case. It appears that, even in the current climate, this is a very low probability event. In other words: a fluke. They write it themselves as the statistical equivalent of really bad luck, really bad luck.
A version of this article also appeared in NRC Handelsblad on July 8, 2021