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Heat waves hitting U.S. and Europe 'virtually impossible' without climate change, researchers say

The findings comes from a consortium of climate scientists who study extreme weather and publish rapid findings about climate change’s role in major events.
A San Bernardino County firefighter wipes his head as the Oak Fire burns near Fontana, Calif.
A San Bernardino County firefighter wipes his head in Fontana, Calif., on July 19. David Swanson / AFP via Getty Images

The heat waves simultaneously broiling the southwest United States and southern Europe would have been “virtually impossible” if not for climate change, according to a group of scientists who study the probability of extreme weather events. A third heat wave, in China, could have been expected about once every 250 years if global warming weren’t a factor.  

“The role of climate change is absolutely overwhelming” in producing all three extremes, said Friederike Otto, a climate scientist at Imperial College London, who contributed to the new research, which was published Tuesday by the World Weather Attribution group. 

The group is a loose consortium of climate scientists who study extreme weather and publish rapid findings about climate change’s role in major events. Their research methods are published and peer-reviewed, but this specific, rapid analysis has not yet undergone a typical academic review process. Previous analyses by this group have held up to scrutiny after their initial release and were ultimately published in major academic journals. 

Global warming has increased the likelihood of extreme temperatures so significantly that heat waves as powerful as the ones setting records in places like Phoenix, Catalonia and in China’s Xinjiang region this July could be expected once every 15 years in the U.S., once every 10 in southern Europe and once every five in China, the research found. 

“This is not a surprise. This is absolutely not a surprise in terms of the temperatures, the weather events that we are seeing,” Otto said at a news conference. “In the past, these events would have been extremely rare.”

The analysis provides another example of how shifts in global average temperatures can create conditions for new, harmful extremes. The scientists warned that the extremes observed this year are expected to worsen as humans continue to emit heat-trapping gasses and rely so heavily on fossil fuels. 

“This is not the new normal, as long as we keep burning fossil fuels. As long as we keep burning fossil fuels, we will see more and more of these extremes,” Otto said. 

Six climate scientists contributed to the recent study. It evaluated an 18-day stretch of high temperatures across the U.S. Southwest and northern Mexico, a seven-day stretch of high temperatures in Europe and a 14-day stretch of maximum measures in China’s lowland regions.  

The heat has been blamed for record-breaking power demand in China and outages in the U.S. and Europe, as well as crop losses or cattle deaths in all three regions, the report found.  

This summer has set records at a staggering pace. 

The Earth saw its hottest June in modern times and also experienced its unofficial hottest days on record in July. Phoenix on Sunday marked its record 24th consecutive day of temperatures at or above 110 degrees Fahrenheit, according to the National Weather Service. A township in Xinjiang, China, hit 126 F and set a national high temperature record. Heat in Europe has shattered records and caused the closure of major tourist attractions.  

The heat wave that’s dogged the southern U.S. for much of July will soon expand to cover much of the country, according to the National Weather Service. 

And it’s not just heat creating hazards across the U.S. The country has experienced a summer of extreme smoke from record-setting Canadian wildfires, extreme precipitation that caused damaging flooding in the Northeast and extreme ocean temperatures along much of its coastline. 

Governments need to better adapt to protect people from heat, Julie Arrighi, of the Red Cross Red Crescent Climate Centre, said at the news conference. 

“They are events that we should be able to manage within our systems,” Arrighi said. “It underscores the need for our systems to adapt much faster, because the risks are rising faster than we are adapting.”