This high-quality study, using data from multiple European countries, provides valuable insights into the impact of non-optimal temperatures on non-accidental mortality.

The analysis is based on a previous Lancet paper which assumes that the effect of temperature on all-cause non-accidental mortality is constant between 2000 and 2019.  Previous studies, including one with overlapping data have reported a decrease in heat-mortality impact over time, due to factors including infrastructural changes and improved health care.  Not accounting for this is expected to overestimate the future impact of heat on mortality.

According to the literature, it is expected that most estimated deaths are likely among individuals with underlying chronic conditions, such as cardiovascular or respiratory diseases, or those with pre-existing mental health challenges.  Moving forward, it will be crucial to differentiate the specific impact of temperature on these conditions and to account for their evolving trends when making projections.

The results are broadly in line with what existing research has shown in multiple contexts around the globe – namely, that temperature extremes do not affect everyone equally, with the elderly and the least well-off being most at risk. What is especially striking is that the authors find clear differences in risk across country boundaries and also regional clusters of mortality risk. Temperature gradients do not respect borders, so as the authors point out, this shows how demographic and socio-economic factors influence the risk we face from temperature extremes. There are countermeasures we can take, which may be particularly effective if they are targeted towards the most vulnerable people and places. For example, the study points to investment in health infrastructure, the presence of heat- and cold preparedness plans, and the quality of the buildings we live and work in as factors that could reduce mortality under a changing climate.