Meteorologists and experts warned us in good time. That the mercury would rise, that even more temperature records would fall, that conditions would become increasingly unbearable. Those warnings went unheeded, and the steps taken to tackle climate change proved far too few.
The course we’re now living through, then, was already set. Summers have stopped being a season of leisure and holidays, as the extremely high temperatures being recorded turn everyday life into a gruelling ordeal. We’re no longer simply talking about hot days and nights, but about conditions that are difficult to manage, with hundreds if not thousands of deaths, energy systems being pushed to their limits, and infrastructure literally breaking down.
You often hear the argument that summers have always been tough and hot. The truth, however, is that it isn’t just summers that have changed, but every season, since the planet’s average temperature has risen by around 1.4°C since humans began burning fossil fuels, releasing gases into the atmosphere that intensify the greenhouse effect.
As a result, extreme heatwaves that used to be recorded once every several years are now occurring annually, and in fact two or three times a year. At the same time, they are more intense and more prolonged. We’re now seeing temperatures that would have been unthinkable just a few decades ago.
Data shows that this June was among the hottest months ever recorded in Europe, with temperatures reaching unprecedented levels in many countries. And this is only the beginning. The World Health Organisation (WHO) warns that summers ahead will be even harder. “This heatwave is a rehearsal,” said Dr Hans Henri Kluge, WHO Regional Director for Europe. Europe is warming at more than twice the global average rate, and heatwaves are no longer isolated, extreme events. They are recurring crises, becoming ever more frequent, intense and prolonged.
At the same time, extreme heatwaves represent a very serious economic challenge, with knock-on effects across numerous sectors. For years we measured heatwaves in degrees Celsius. It’s time we started measuring them in euros too. Every extra degree now writes a new line of cost — on electricity bills, on insurance premiums, on compensation payouts, on lost working hours, on agricultural output, on tourism, on public spending. The real question, then, isn’t whether the temperature will hit 42 or 44 degrees in the near future. It’s how much each additional degree costs.
For now, what we know for certain is just how severe the consequences are. Reduced productivity caused by heatwaves — particularly in outdoor work such as construction, agriculture and tourism — translates into significant economic losses. At the same time, electricity consumption rises sharply due to widespread use of air conditioning, placing further strain on energy networks and driving up costs for households, businesses and states alike. Heatwaves also drive up spending on healthcare, civil protection and firefighting, while damage to infrastructure and crops places an even greater burden on national economies.
The International Labour Organisation estimates that by 2030, heat stress will lead to the loss of 2.2% of total working hours worldwide — equivalent to around 80 million full-time jobs — while a study by the European Commission’s Joint Research Centre found that by the middle of the century, many European regions will be losing more than 1% of annual labour productivity to heat. In the hottest areas, losses could exceed 2%–6%.
Meanwhile, a study by the University of Mannheim and the European Central Bank calculated that extreme weather events in the summer of 2025 — heatwaves, droughts and floods — cost EU economies around €43 billion, or roughly 0.26% of gross value added, and that without meaningful adaptation, this cost could climb to €126 billion in the coming years.
Allianz Trade estimates that recurring extreme heatwaves could shave up to 0.5 percentage points off Europe’s annual growth rate, with southern European countries — Spain, Italy, Cyprus and Greece among them — ranking among the most vulnerable.
At the same time, heatwaves are widening social inequalities, as those who are economically disadvantaged often lack access to adequate cooling or live in areas with limited green space and pronounced urban heat island effects. Prolonged exposure to heat also affects mental health, quality of life and social cohesion, making it one of the most significant public health and social policy challenges of the coming decades.
Stavros Dafis: We haven’t seen the worst of the heatwaves yet
Europe is the fastest-warming continent in the world, and the trend in the frequency and intensity of extreme episodes is steadily rising
Extreme heatwaves are no longer a rare summer occurrence — they are becoming one of the greatest challenges of the climate crisis. Temperatures shattering every previous record, prolonged spells of unbearable heat and nights offering no meaningful relief are testing the limits of human endurance, straining healthcare systems, raising the risk of wildfires and causing significant economic losses. Scientists warn that Europe is warming faster than any other continent, and that the Mediterranean is among the regions set to be hit hardest in the decades ahead.
How closely linked are increasingly extreme heatwaves to climate change? What do the scientific models show for Cyprus and the Eastern Mediterranean? How prepared are European cities for temperatures that, until recently, seemed unthinkable — and how might a potential strong El Niño affect the situation? Physicist and meteorologist Dr Stavros Dafis, a member of the research teams at the National Observatory of Athens/meteo.gr and climatebook.gr, speaks to Phileleftheros about the causes and outlook for the phenomenon, explains why this year’s heatwaves are a warning for the future, and describes what needs to happen now if we are to avoid facing an even more extreme climate reality.
Why do such extreme heatwaves occur, and how are they linked to climate change?
They occur when a stable high-pressure system — often an “omega block” — traps warm air over a region for days on end. Climate change doesn’t create the phenomenon itself, but it amplifies it thermodynamically: in the attribution analysis we carried out for this year’s heatwave, the same atmospheric conditions now produce temperatures up to 2.5°C higher than they would have decades ago. It’s the combination of natural variability — a warmer Atlantic, for instance — and human-driven warming that makes the difference.
What are the characteristics that make a heatwave extreme?
Three factors: intensity — how far above normal the temperature climbs; duration and persistence; and the absence of night-time cooling. An ordinary heatwave breaks records by tenths of a degree and eases off within a few days. This year’s latest heatwave broke records by 2-3 degrees, with tropical nights that gave the body no chance to recover. That statistical deviation is the real signal of an unusual event. In the past, high temperatures mainly appeared in July and August, for shorter periods and over a more limited geographical area of Europe — this year they had already begun by May. As climatologist Erich Fischer of ETH Zurich has also explained, what’s unusual isn’t just that records are broken, but by how much: if a record falls after 100–150 years of measurements, you’d expect it to be exceeded by a tenth of a degree, not suddenly by two or three degrees.
Can safe predictions be made for the coming years regarding rising temperatures?
Europe is the fastest-warming continent in the world, and the trend in the frequency and intensity of extreme episodes is steadily rising. At 2°C of warming, deaths from heat stress are expected to triple compared with 1.5°C. We’re not talking about the distant future — the effects are already measurable. The Mediterranean is warming at a rate roughly 20% faster than the rest of the planet, so the trend remains upward regardless of what happens specifically in Cyprus this year.
What do the models show for the Eastern Mediterranean and Cyprus?
The region is classed by the IPCC as one of the most vulnerable climate hotspots, warming faster than the global average. Under the adverse scenario, models show a 2°C rise by the 2050s, which could reach 3°C by the end of the century compared with 1986–2005 levels. At the same time, rainfall is projected to fall by up to 20% by the end of the century.
What do you believe will be the consequences of prolonged heatwaves and rising temperatures more broadly?
We’ll see consequences for public health, such as cardiovascular strain and increased mortality, particularly among vulnerable groups. On health specifically, the leading cause of death is cardiovascular. As the body works to shed heat, it goes into overdrive, and beyond a certain point vital functions — mainly the heart — are affected. This can lead to cardiac collapse. Tropical nights play a decisive role here. When the temperature doesn’t drop even at night, the body doesn’t get the chance to recover, and heat stress becomes cumulative day after day instead of resetting. For infrastructure, there’s pressure on energy networks, transport and hospitals. For agriculture, reduced output in crops and livestock farming. And at ecosystem level, heightened risk of wildfires and water shortages.
Can extreme temperatures affect even countries accustomed to heat, such as Cyprus or Greece?
Yes, because “being used to it” has its limits. Greece’s and Cyprus’s records sit at around 46-48°C, but when we see records elsewhere being broken by 2-3 degrees instead of tenths, that same scale of deviation applied to Greek or Cypriot values brings us close to 50 degrees. Familiarity with heat helps with acclimatisation, but it doesn’t override the body’s physiological limits when faced with unprecedented intensity.
How prepared are European cities, and what steps are needed to protect them against extreme heatwaves?
They’re inadequately prepared, especially in the north. Only around 20% of European homes have air conditioning, and much of the housing stock was built to retain heat, not release it. What’s needed are early warning systems, urban greenery, district cooling — as is being trialled in Paris — and action plans for the most vulnerable groups.
There have recently been forecasts of a particularly strong El Niño that will push temperatures up further. What is this phenomenon, and how is it expected to affect us?
It’s the warm phase of a natural cycle (ENSO) in the tropical Pacific, which alternates with La Niña every few years. El Niño is currently developing, with scenarios pointing to it strengthening towards the winter of 2026-27. In Europe, its direct impact is more indirect than in the Americas or Asia, but it does contribute to global temperature records, with the most significant effects expected during 2027.
Could a strong El Niño worsen water shortages and wildfires this autumn in Cyprus and Greece, particularly during a period of economic downturn?
A strong El Niño on top of an already warmer planet could intensify drought and extend the high wildfire-risk period in Cyprus and Greece. The timing is doubly burdensome, as it would follow a summer that has already depleted water resources and forest reserves. That said, the greatest impacts of El Niño are expected later, from the winter of 2027 onwards.
A final, hypothetical question. Let’s imagine it’s 2040. Based on what we are or aren’t doing today, how do you picture the climate situation, temperatures, and the frequency or intensity of heatwaves will have developed?
If the emissions trajectory doesn’t change substantially, by 2040 this year’s heatwaves will look ordinary. The Mediterranean will have warmed noticeably above the global average, with more frequent, more intense and more prolonged episodes. The difference between a better and a worse 2040 won’t be decided in the future — it’s being decided now, in the energy policy and resilience decisions being made today.
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