Jul 28, 2022 - Energy & Environment

Global warming sharply escalated the risk and severity of the UK heat wave: study

Man on London subway fans himself with newspaper during a heat wave.

A man uses a newspaper as a fan whilst travelling on the Bakerloo line in central London during a heat wave on July 18, 2022. (Photo by Yui Mok/PA Images via Getty Images.)

Human-caused climate change tipped the scale dramatically in favor of the record-shattering U.K. heat wave that struck the country last week, a new study concludes.

Why it matters: Extreme weather and climate events are a big part of how society is experiencing global warming, and this study clearly lays out the present-day consequences of greenhouse gas emissions.

The big picture: The extreme event attribution study sought to find out how climate change from the burning of fossil fuels and other factors is altering the odds and severity of extreme heat events in the U.K.

  • It found that the U.K. heat wave, which peaked on July 18 and 19, setting a record for the hottest temperature in the history of the U.K., at 104.54°F (40.3°C), was at least 10 times more likely to occur in today's warmer climate compared to the preindustrial era.
  • It also found that the heat wave's average temperatures were at least 3.6°F (2°C) milder than they would have been in a world without today's high atmospheric concentrations of greenhouse gases.
  • On July 19, an astonishing total of 34 weather stations broke the previous all-time national temperature record, according to the UK Met Office.

Between the lines: To determine the effect of climate change on the high temperatures in the UK, 21 scientists from around the world used historical weather data and computer model simulations to determine the frequency and severity of such events in today's climate, after about 2.16°F (1.2°C) of global warming since the preindustrial era.

  • This was then compared with computer model simulations of such a heat event's occurrence in a climate lacking today's high greenhouse gas concentrations.

Yes, but: The study notes that it likely underestimates global warming's influence on this event, and therefore on the odds and severity of similar events in the future.

  • With the UK heat wave as well as the extreme event in the Pacific Northwest last year, some climate scientists have been asking the question of whether their computer models have been underestimating the dangers of once unthinkable extreme events.

The intrigue: One complication the researchers found when looking at the UK heat is that the frequency and severity of extreme heat in western Europe is already increasing faster than computer models have projected.

  • The models show a 3.6°F (2°C) increase in temperatures during this heat wave, but historical data shows double that.

What they're saying: “In Europe and other parts of the world we are seeing more and more record-breaking heatwaves causing extreme temperatures that have become hotter faster than in most climate models," said Friederike Otto, a researcher at Imperial College London who co-directs the World Weather Attribution group, in a statement.

  • "It’s a worrying finding that suggests that if carbon emissions are not rapidly cut, the consequences of climate change on extreme heat in Europe, which already is extremely deadly, could be even worse than we previously thought,” she said.

The bottom line: This new attribution study adds to the mounting evidence that human-caused global warming, largely from burning fossil fuels to generate energy, is making the planet hotter and more volatile, with cascading risks from extreme events.

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