Following a record hot June, large areas of the US and Mexico, Southern Europe and China experienced extreme heat in July 2023, breaking many local high temperature records.

July 2023 saw extreme heatwaves in several parts of the Northern Hemisphere, including the Southwest of the US and Mexico, Southern Europe and China. Temperatures exceeded 50C on the 16th of July in Death Valley in the US as well as in Northwest China (CNN,2023). Records were also reached in many other weather stations in China and the all-China heat record was broken in Sanbao on the 16th of July. In Europe, the hottest ever day in Catalunya was recorded and highest-ever records of daily minimum temperature were broken in other parts of Spain. In the US, parts of Nevada, Colorado and New Mexico tied their all time high, parts of Arizona, Cayman Islands, highest ever night time temperatures in Phoenix Arizona which also had its record for longest time without falling below 90F/32.2C.

Several heat deaths have been confirmed in the US, including migrants on the US Mexican border. In Mexico alone over 200 people died due to the heat. Spain, Italy, Greece, Cyprus, Algeria, and China also reported heat deaths, as well as a large increase in hospitalisation due to heat related illnesses. Large parts of the population in Italy and Spain and over 100 million people in Southern US are under heat alerts. In all three regions, demand for power spiked and negatively impacted a number of important crops, including olive oil in Spain and cotton in China.

Scientists from the World Weather Attribution initiative collaborated to assess to what extent human-induced climate change altered the likelihood and intensity of the extreme July heat in these three regions.

Hittegolven in Zuid-Europa waren zonder klimaatverandering ‘vrijwel onmogelijk’