With extreme heat becoming an increasingly routine part of weather forecasts, health experts are raising the alarm over the potentially fatal risk of rising temperatures.
But it’s challenging to parse exactly how heat kills, since it can contribute silently to other causes of death, such as heart and immune diseases. I spoke to Joan Ballester, a scientist at IS Global in Barcelona, whose team tackled this question by creating a model to provide the best estimate of how many deaths were linked to the hottest summer on record in 2022 in Europe. They looked at mortality rates in 35 countries, concentrating on short-term periods when temperatures soared. They correlated deaths with temperature fluctuations and even after accounting for other factors that could explain the deaths, found the heat contributed to additional mortality that would not otherwise have occurred. Here’s what the analysis showed: