Last week, Portugal endured its most intense May heatwave on record, with temperatures soaring to 42.6°C in the Alentejo region. For context, that is 15°C above the seasonal average, a deviation that would be alarming even for high summer. This event is not an anomaly. It is a data point in a relentless trend. The Iberian Peninsula has become a crucible of climate extremes, and the UK, despite its relatively temperate latitude, is not sheltered from the consequences.
As a climate correspondent, I have spent years tracing the physical connections between global warming and local weather. The mechanism is straightforward: atmospheric circulation patterns, such as the jet stream, are becoming wavier due to Arctic amplification. This allows hot air from North Africa to surge northward with increasing frequency and intensity. Portugal’s heatwave is a direct result of a stalled high-pressure system, a pattern we have observed more often in the last decade. The UK’s own heatwaves in July 2022 and June 2023 followed similar dynamics.
But the urgency extends beyond meteorology. Portugal’s heatwave triggered multiple wildfires, strained energy grids, and caused a spike in hospital admissions for heat-related illnesses. These are not abstract impacts. They are fiscal and human costs that will escalate as global temperatures rise. The UK, as a developed nation with significant historical emissions, has both a moral and strategic imperative to lead. Our current trajectory of emissions reductions is insufficient. The Climate Change Committee’s latest progress report underscores that we are off track for meeting our 2030 Nationally Determined Contribution (NDC).
Consider the energy transition. Portugal has invested heavily in renewables, sourcing over 60% of its electricity from renewable sources in 2023. Yet its heatwave exposed vulnerabilities in grid resilience and water availability for hydropower. The UK can learn from this: a rapid buildout of diversified renewable capacity, coupled with grid modernisation and storage, is non-negotiable. We have the technical solutions: offshore wind, solar, tidal, and advanced nuclear. What we lack is the political will to implement them at scale.
The temptation is to view such extreme events as distant tragedies, but climate physics does not respect borders. The same Rossby waves that baked Portugal will bring droughts to the UK’s agricultural regions and exacerbate flooding from stalled rain bands. Our infrastructure, from railways to housing, is not designed for 40°C days. The National Health Service already faces increased strain during heatwaves. Every fraction of a degree of warming worsens these risks.
Leadership means acknowledging the data without despair. It means implementing carbon pricing, banning new gas boilers, and investing in public transport. It means being honest with the public about the scale of behavioural and technological change required. The UK has a unique platform: our scientific expertise, financial markets, and diplomatic influence can drive global action. But this requires a government that treats climate change as the primary threat it is, not a secondary concern.
Portugal’s heatwave is a warning shot. The UK must now demonstrate that it can translate knowledge into action. The cost of failure is not measured in temperature anomalies, but in lives and livelihoods. The moment for calm urgency is now.
