Climate Change

Heatwaves in Europe, North America ‘virtually impossible’ without anthropogenic emissions: WWA

The heat event in China was made 50 times more likely by human-induced climate change

By Rohini Krishnamurthy
Published: Tuesday 25 July 2023
In US-Mexico & southern Europe, heatwaves in 2022 would not have occurred without humans pumping greenhouse gases into the atmosphere. Photo: iStock__

Heatwaves that hit North America and Europe would have been “virtually impossible” without human-induced climate change, a new report found.

Similarly, climate change made heatwaves in China 50 times more likely, according to the attribution analysis by World Weather Attribution (WWA), a collaboration of scientists involved in quantifying how climate change influences the intensity and likelihood of an extreme weather event.

“The result of this attribution study is not surprising. The world hasn’t stopped burning fossil fuels, the climate continues to warm and heatwaves continue to become more extreme. It is that simple,” Friederike Otto, senior lecturer in climate science at the Grantham Institute for Climate Change and the Environment, Imperial College London said in a statement.

Temperatures in Death Valley in the United States and northwest China crossed 50 degree Celsius on July 16, 2023. Land surface temperatures hit 46°C in Rome, Italy, while that in Madrid and Seville reached 46°C and 47°C, respectively.

“Once again, our study showed the significant impact of the rapid rate of warming on local temperatures in Europe,” Sjoukje Philip, researcher at the Royal Netherlands Meteorological Institute, noted. 

She stressed that Europe needs to continuously take adaptation and mitigation measures.

Many people from North America, including from Texas, California, Arizona, New Mexico and Nevada in the US, as well as Baja California, Sonora, Chihuahua, and Coahuila in Mexico have been affected. Spain, Italy, Greece and the Balkan states neighbouring the Mediterranean and China also suffered.

Using peer-reviewed methods, scientists analysed how human-induced climate change altered the likelihood and intensity of 18-day average maximum temperatures over the most affected regions in the western United States, Texas and northern Mexico.

They also looked at seven-day average maximum temperatures over land over southern Europe and 14-day average maximum temperatures over the lowlands of China.

They found that the event in China would have been about a 1 in 250-year event without anthropogenic climate change. Whereas in the US-Mexico region and southern Europe, the heatwave would not have occurred without humans pumping greenhouse gases into the atmosphere. Scientists said the event was made at least 1,000 times more likely.

The 2022 heatwave in Europe resulted in the death of more than 61,000 people in Europe between May 30 to September 4.

Previously, in July this year, scientists from WWA were not able to pinpoint the role of climate change in the deadly May floods in Rwanda and the Democratic Republic of Congo (DRC), which killed some 135 people in Rwanda and 460 in DRC.

This, they said, was due to a lack of weather station data. Consequently, climate models could not simulate the event. 

The heavy rainfall led to severe flooding and hundreds of landslides around Lake Kivu, on the border between Rwanda and the DRC. Rwanda received 182.6 mm of rainfall, breaking its maximum daily rainfall record. 

“We know the rainfall around Lake Kivu was extreme, in terms of the destructive impacts it triggered. However, due to incomplete and inaccessible meteorological records, we don’t know how to qualify it as an extreme event,” Dieudonne Nsadisa Faka, team leader of the intra-ACP Climate Services Programme of The Organisation of African, Caribbean and Pacific States, Brussels, Belgium, said in a statement.

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