The Lancet Planetary Health, March 2025

The mortality and associated economic burden of London’s summer urban heat island effect: a modelling study

Climate change is increasing the frequency and intensity of heatwaves around the world. At the time of writing, the summer of 2018 holds the record for the highest average summer air temperature ever recorded in the UK, and a record-breaking maximum air temperature (since surpassed) of 34·4°C was measured at Greater London Heathrow Airport.

From the UK’s official climate projections, it was reported that observed changes to the climate have already increased the probability of experiencing a summer as hot as 2018 by 12–25%, and that this is projected to increase to 50–60% by mid-century. During periods of heat in 2018, 863 excess deaths of people older than 65 years were recorded by the UK Office for National Statistics (ONS).