Human-caused climate change made the record-breaking heat wave currently scorching Europe possible, scientists concluded in a new study released Friday. The findings came from the World Weather Attribution group, an international team of researchers from Europe, the United States and the United Kingdom.
The study found it would have been virtually impossible for temperatures this extreme to occur in Europe during June fifty years ago. Researchers compared the current heat wave against how similar weather patterns would have behaved in the cooler climates of 2003 and 1976.
The numbers are stark. A comparable heat wave in June 1976 would have been 3.5 degrees Celsius cooler during the day. Even compared to 2003, when tens of thousands of people died in a major European heat wave, the current episode was notably extreme. A similar event in that year would have been about 2 degrees Celsius cooler, the study said.
"This event would not have been possible in June without climate change," said Theodore Keeping, the study's lead author from Imperial College London, speaking to reporters. Keeping also noted that "the chance of a heat wave like this has changed immensely."
Co-founder of World Weather Attribution Friederike Otto, also from Imperial College London, addressed the nature of the event directly. "The weather pattern itself is not particularly unusual, but the temperatures are — or at least they used to be, without human-induced climate change," she told reporters.
The study also addressed a possible natural factor. The El Niño weather pattern had "no role in driving the heat," the authors said. The warming driving these events comes from burning coal, oil, and gas, which has pushed the planet roughly 1.4 degrees Celsius above preindustrial temperatures.
Europe is the world's fastest-warming continent, according to the report on Phys.org. Tens of millions of people have sweltered this week in temperatures that broke records in several countries. Of nearly 850 cities in Europe analyzed in the study, about 45 percent had broken or were expected to break their all-time heat stress records in June.
Heat stress occurs when the body's natural cooling systems are overwhelmed. Symptoms range from dizziness and headaches to organ failure and death. Otto singled out the combination of high temperatures and humidity as a particular threat in this event.
The study's own language left little room for ambiguity. "Our analysis here shows that intense heat is increasing rapidly even in living memory, with such events tens to hundreds of times more likely since only 2003 and virtually impossible just 50 years ago," it stated. "Climate change is unequivocally to blame."
Because the heat wave was still unfolding at the time of publication, scientists used both observed and forecast temperatures in their analysis.
