Study estimates summer heat killed more than 50,000 in Europe's cities

The modeling study estimated 50,391 excess heat-related deaths in 854 cities across 30 European countries this summer and attributed 32,619 of them to human-caused warming. The cities hold about 40% of those countries' population, so the figure does not cover all of Europe.

The researchers note the numbers are modeled estimates rather than counted deaths. They say the toll may be understated because the study leaves out heat in May and relies on coarse temperature data.

Why it matters: The estimate covers hundreds of cities and links most of this summer's heat deaths there to human-caused warming rather than natural variation.