The mercury has shattered records across the continent this week, and so too have the assumptions underpinning our fiscal models. Germany clocked 41.7 degrees Celsius on Wednesday, a figure that would have seemed hypothetical a decade ago. The human toll is now confirmed at 1,300 dead across Europe, a number that will almost certainly rise as the heatwave continues its merciless grip on the continent. For markets, this is not just a weather story. It is a structural shift that demands a repricing of risk, from agricultural yields to energy demand and government balance sheets.
Let’s be clear: extreme heat is a tax on growth. The energy sector is strained to breaking point as air conditioning loads surge, pushing spot electricity prices to levels not seen since the 2022 gas crisis. But unlike that shock, this one is not transitory. Climatologists from the British Met Office are now speaking of a ‘new normal’ where 40C events become routine. If that is the case, then the long-run equilibrium for energy costs needs to be revised upward, and that means higher inflation expectations baked into the yield curve.
The human cost is devastating, but the economic consequences are also significant. Tourism in Southern Europe is taking a hit, with holidaymakers cancelling trips to Spain and Italy. Construction productivity plummets when workers cannot operate safely in the heat. And agriculture? Crop yields for wheat and maize are already being revised downward across France and Germany. That has implications for food price inflation, which central banks can do very little about.
Meanwhile, the British government, facing its own heatwave, is under pressure to accelerate net-zero spending. The fiscal multiplier from green infrastructure is attractive on paper, but the timing could not be worse. With gilt yields already elevated due to persistent core inflation, any additional borrowing risks crowding out private investment. The Chancellor must walk a tightrope between climate adaptation and fiscal credibility. So far, the market is not convinced.
Investors should watch the energy sector closely. Renewables are part of the solution, but they struggle with intermittency. When the wind stops blowing and the sun is at its height, gas-fired plants are called upon to fill the gap. That dynamic is supporting European gas prices, which remain stubbornly high. The net effect is a transfer of wealth from consumers to energy producers, a tax on spending that depresses demand.
Capital flight is also a concern. If extreme weather events become more frequent, countries with weaker fiscal positions and less adaptive capacity will see a risk premium attached to their debt. Look at Italy, where the spread over Bunds is already widening. Climate risk is now a credit risk.
In the City, we pride ourselves on rationality, but the market’s response to this heatwave has been surprisingly muted. Perhaps it is because the tragedy of 1,300 deaths does not fit neatly into a spreadsheet. But make no mistake: the numbers are moving. Insurers are quietly hiking premiums. Farmers are hedging more aggressively. And central bankers are starting to mumble about the supply side effects of climate change.
The real question is whether we will adapt fast enough to prevent this from becoming a persistent drag on growth. Or will we double down on the same old policies, hoping the mercury drops on its own? I wouldn’t bet on it.
Alastair Thorne
