Heatwaves pose a new downside risk to European growth, ING's Carsten Brzeski says in a note. Germany, France and the U.K. among others experienced their hottest days on record for June in the last week. A 2021 study of Europe's worst heat years put GDP losses from reduced labor productivity alone at 0.3%-0.5%, exceeding 1% in the most exposed regions, Brzeski says. Add rising healthcare costs, emergency infrastructure repairs and the impact of heatwaves on waterways, transportation or agriculture, the economic hit increases further. For northern European countries like Germany, infrastructure, housing stock and sectors like construction and logistics were built for a cooler climate and haven't adapted to the new reality. "Thermometers, it turns out, have become a leading indicator of economic growth," Brzeski adds. (edward.frankl@wsj.com)