World Weather Attribution says fossil fuel emissions have rapidly worsened European heatwaves

Scientists with World Weather Attribution say the late-June European heatwave was sharply worsened by fossil-fuel-driven climate change, as official weather agencies confirmed record or near-record temperatures and widespread heat alerts across the region.

The rapid attribution analysis, released June 26, says the event would have been virtually impossible 50 years ago and about 200 times more likely than 20 years ago. Researchers also said the heatwave was the most severe and widespread to hit such a large part of Europe.

AP reported that the study examined observed temperatures and forecasts for a heat event that began on June 18. It found that 45% of 850 cities analyzed across 30 European countries broke or were expected to break heat-stress records.

The comparison years used in the analysis were 1976 and 2003, according to AP. The researchers said the current event would have been cooler in both eras.

How the heatwave unfolded

The event began on June 18 and intensified through the following week as hot weather spread across multiple countries, including France, Italy, Spain and the UK. European weather agencies issued red alerts, and some schools, sports events, public transport and attractions were restricted because of the heat.

The Guardian reported that scientists described the heatwave as the most severe and widespread to hit such a large region of Europe. The reporting also tied the event directly to the fossil-fuel warming that has raised the baseline risk of extreme heat.

AP said Europe is the world’s fastest-warming continent, with temperatures increasing at twice the global average since the 1980s, according to Copernicus. That broader warming trend is helping make events like this heatwave more dangerous and more common.

Record heat and official warnings

National weather agencies have already confirmed major temperature milestones. The UK Met Office said on June 25 that the country provisionally set a new June maximum temperature record for a second consecutive day, reaching 36.7C in Merryfield, Somerset.

The Met Office said that reading exceeded the previous June record of 35.6C set in 1976 and 1957. It also said the heatwave showed how extreme temperatures are becoming increasingly common in the UK as a result of human-induced climate change.

Axios reported that WWA’s statement said overnight temperatures were about 100 times more likely today than in 2003, while daytime peaks were about 10 times more likely. That matters because dangerous heat does not stop when the sun goes down, and overnight relief is limited.

High humidity has added to the risk profile because heat stress depends on both temperature and moisture. In practical terms, that can increase strain on hospitals, emergency services, transport systems and people without effective cooling.

Why it matters now

The immediate stakes are public health and infrastructure. Dangerous daytime heat and hot nights can worsen illness, raise mortality risk and increase demand on hospitals, while also affecting schools, travel networks and public events.

The heatwave has also become another data point in climate attribution science. World Weather Attribution is a rapid attribution collaboration that studies how climate change affects extreme weather events, using established methods to compare present-day conditions with past climate baselines.

AP said the study is not peer reviewed, but it uses peer-reviewed methodology. That means the results are meant to be fast-moving and policy-relevant, while still leaving room for later verification and additional detail.

What comes next

Researchers and officials are still watching for the full WWA statement and any underlying report details on methodology and event definitions. Final confirmation is also still pending on some temperature records and on the total health impact across the region.

Open questions include whether other national agencies will confirm additional records, and how many deaths, hospitalizations and disruptions will ultimately be counted. Follow-up reporting is also likely to clarify how severe this heatwave was relative to previous European extremes.

For now, the basic finding is clear: scientists say fossil-fuel emissions have made Europe’s late-June heatwave far more intense and far more likely, while weather agencies across the continent continue to document the real-world effects.