The summer of 1976 was an extraordinary heatwave for its time. With 15 consecutive days of temperatures over 32°C, it was an unprecedented length for a UK heatwave, coming at the end of a year-long drought. This led to severe water shortages and frequent wildfires, followed by flash floods.
But the climate has substantially changed since 1976. Global temperatures have risen by about 1°C since then and summer 2025 was hotter than 1976 for the UK, with three shorter heatwaves rather than one long one.
When we zoom out to a global perspective, the change becomes even more stark. We are now living in a very different climate compared to just 50 years ago.
In summer 1976, northwest Europe was a lonely hot spot in a sea of cooler temperatures. In summer 2025, the whole world was hot (bright red), with record-shattering heat in many regions.
Warmer world, hotter heatwaves
But what if the weather patterns of 1976 happened again now in today’s warmer climate?
Greenhouse gas emissions, primarily from burning fossil fuels, already make every summer and every heatwave hotter than it would have been in a world without those emissions.
But unfortunately a 1°C rise in global temperatures does not mean that heatwaves only become 1°C hotter. Extreme heat is intensifying much faster than the average temperature, and since the 1960s, heatwaves in southern England have become 3°C or 4°C hotter in urban and rural areas alike.
Peak temperatures in today’s climate, for a comparable event to the 1976 heatwave, would be 38°C or 39°C. Although this probably wouldn’t break the record for the hottest UK day on record – a temperature of 40°C was recorded on 19 July 2022 – it is similar to the peak temperatures currently forecast in late June 2026.
The 15 consecutive days over 32°C in 1976 would become 15 consecutive days over 35°C (three degrees hotter) in today’s climate. The UK has only ever had three consecutive days over 35°C before, and even the current heatwave is forecast to only extend for a few days. 1976 is no longer the hottest heatwave, but it remains notable for being hot for such a long time.
So, the upward shift in temperature from global warming has created more dangerous heatwave conditions. Hot daytime temperatures, coupled with very warm nights making it hard to sleep, would cause huge health issues for vulnerable people, and reduced productivity even for healthy people.
We saw this in May 2026, when temperatures reached a staggering 35.1°C, shattering the May temperature record. Britain’s roads and railways are already disrupted in short heatwaves. Imagine such a heatwave happening in school exam season with teenagers sitting in stifling halls hoping to secure their future careers. How would your parent cope trying to recover after surgery in a hot hospital ward? Could you concentrate and be productive in your non-air-conditioned workplace building? Watching or playing outdoor sports would be much less enjoyable and potentially unsafe.
UK society and the infrastructure on which it depends is built for a climate that no longer exists. It is urgent that it adapts to weather extremes happening already and those anticipated in the next few decades.
Journalists should report that greenhouse gas emissions, primarily from burning fossil fuels, have made all heatwaves hotter and more deadly than they would otherwise have been.
And they should use photographs of the serious consequences of extreme heat instead of those of people fortunate to be enjoying time at the beach.
Future heatwaves depend on choices today
Summers in the UK are notoriously variable and 2024 might have felt relatively cool to most, but to someone who experienced the summers of 1888 or 1922 it would have felt rather hot.
What is “normal” has already changed. The climate of the past no longer exists. Summers in the UK have become hotter, and 2025 was the warmest on record.
For now.
With continued greenhouse gas emissions, UK summers will become hotter, with more frequent, more intense and longer heatwaves. Met Office climate model projections suggest the UK could begin to experience temperatures of 45°C within the next three decades, with plausible heatwaves hitting 40°C for over a week in a world which is 2.5°C warmer than pre-industrial levels.
Britain’s climate and its way of life will become unrecognisable.
To put this into perspective, when a child born today becomes a parent, the average temperatures of summer 1976 will be normal. When they become a grandparent, they will look back and think that the summer of 1976, or even the summer of 2025, were remarkably cold.
But we have a choice. As a global society, we could rapidly reduce our reliance on fossil fuels, reverse deforestation, restore nature, and stabilise greenhouse gases in the atmosphere. This would allow us to live in a world with a stable climate and cleaner air to breathe.
We will still live in a world much hotter than 1976. And until then heatwaves will get longer and hotter so we still need to adapt our way of life. We have no choice about that. But we can still avoid the worst consequences if we act urgently.
Every year we delay in cutting emissions means a hotter and more extreme future climate.
Ed Hawkins receives funding from UKRI and the EU Copernicus Climate Change Service.
Hayley J. Fowler receives funding from UKRI, the Royal Society, the Natural Environment Research Council, the Medical Research Council and the Engineering and Physical Sciences Research Council. She is a member of the UK Climate Change Committee.
