Portugal has recorded its hottest May day on record, with temperatures soaring to 47.2°C in the Alentejo region, according to the Portuguese Institute for Sea and Atmosphere. The previous record, set in 2020, has been surpassed by nearly two degrees. This event is not merely a statistical anomaly; it is a stark physical manifestation of the global energy imbalance driven by greenhouse gas concentrations. The planet is warming at a rate that demands urgent attention, and the repercussions are now being felt across Europe.
The Iberian Peninsula, like many regions, is experiencing what climate scientists call a “heat dome,” a high-pressure system that traps heat and suppresses cloud formation. Such phenomena are becoming more intense and frequent due to climate change. The jet stream, which typically steers weather patterns, is weakening and becoming more wavy, a direct consequence of the amplified warming in the Arctic. This altered behaviour allows hot air to linger over areas like Portugal, stretching the boundaries of what is physically possible.
For Britain, this event serves as a critical reminder of our own vulnerability. The UK has seen a 1.4°C rise in average temperature since pre-industrial times, and models suggest that by 2050, summers like that of 2018, when temperatures exceeded 35°C for weeks, could become the norm. The infrastructure of this nation, from rail lines to hospitals, is not built for such extremes. The 2022 heatwave, which saw temperatures surpass 40°C for the first time, caused an estimated 3,000 excess deaths. This figure is a measure of our lack of preparedness.
The current British government’s approach to climate resilience is a patchwork of adaptations, but the scale of the challenge requires systemic change. To draw an analogy: we are trying to protect our house with a stronger door while a hurricane approaches. We need to rethink the entire structure. The National Adaptation Programme, while a step forward, does not adequately address the cascading risks from water shortages, crop failures, and health impacts. The Committee on Climate Change has repeatedly warned that the UK is underprepared for a 2°C world, let alone the 3-4°C trajectory we are currently on.
Portugal’s record is a data point in a much larger narrative. The energy transition to renewables is underway, but it is too slow. Global emissions continue to rise, and the inertia of the climate system means that even if we stopped all emissions today, the planet would continue to warm for decades. This is the physical reality we face: the greenhouse gases we have already emitted are locked in. The only leverage we have is to mitigate further warming and adapt to what is now unavoidable.
The biosphere is responding. Coral reefs, which act as the ocean’s rainforests, are bleaching at unprecedented rates. The Amazon, which produces 20% of the world’s oxygen, is turning into a carbon source. These are feedback loops that accelerate warming. The collapse of vital ecosystems is not a distant threat; it is happening now. Portugal’s heat record is a canary in the coal mine, but the mine is our entire planet.
Technological solutions, such as direct air capture and next-generation nuclear fission, are promising but far from scaled. The real solution lies in radical energy efficiency, a massive buildout of solar and wind, and a shift in consumption patterns. This is not a moral stance; it is a physical necessity. The laws of thermodynamics do not care about politics.
As a scientist, I have watched the data for decades. The trend is clear. The urgency is real. The calm must be in our response, not in our denial. Portugal’s record is a signal. We must listen.
