Why the June heatwave mattered
From 17 to 28 June, Belgium endured its most lethal heat episode on record. Temperatures in Ukkel peaked at 35.5 °C, while night‑time lows never fell below 24.1 °C – a historic nocturnal minimum dating back to 1892. In that twelve‑day stretch, 1,181 deaths were linked to the scorching conditions, representing roughly a quarter of all fatalities during the period.
Scientists isolate the climate fingerprint
Researchers at the Vrije Universiteit Brussel (VUB) employed a two‑step methodology. First, they used climate models to reconstruct what the heatwave would have looked like without anthropogenic warming. By analysing the twelve warmest consecutive days each year since 1954, they estimated that the event would have been about 3.9 °C cooler, with a confidence interval of 2.2 to 5.7 °C. The average maximum temperature would have been 32.1 °C instead of the observed 36 °C.
Second, they matched these temperature scenarios to established mortality risk curves. Prior studies show that the probability of death rises sharply once a critical temperature threshold is crossed. Applying this relationship, the team concluded that 665 of the heat‑related deaths – 56 % of the total – would not have occurred in a world without human‑induced warming.
Who suffered the most?
Age, gender and socioeconomic status shaped the fatality pattern. People aged 85 and older accounted for half of the heat‑related deaths, reflecting both their vulnerability and the baseline mortality in that cohort. Women died in greater numbers than men, a disparity partly explained by the higher proportion of elderly women. Residents of poorer neighbourhoods were also hit harder, likely because of inadequate housing insulation and limited access to cooling resources.
Regional disparities
The Walloon province of Liège stood out, with an excess mortality rate of 9 to 11 deaths per 100,000 inhabitants. Similar spikes appeared in Hainaut and Namur. In some southern locales, temperatures exceeded the long‑term average by more than 9.5 °C, amplifying health risks.
What the findings imply
Wim Thiery, a climate scientist at VUB and co‑author of the report, emphasised three drivers behind the deadly outcome: Europe is warming twice as fast as the global average, extreme heat events are intensifying even more rapidly, and mortality risk escalates steeply once temperatures breach a critical limit. The study underscores that a seemingly modest rise of a few degrees can push a heatwave over the fatality threshold, especially for older, socially vulnerable groups.
Although the analysis is preliminary and has yet to undergo external peer review, the methodology builds on previously published work and involved collaboration with KU Leuven, UCLouvain and the Royal Meteorological Institute of Belgium. The results add a stark, human‑focused dimension to the broader climate debate.
