Climate change is no longer a future threat. It is a public health crisis we are already experiencing. Its effects are here, intensifying year after year, and claiming thousands of lives worldwide, in Europe, and also in Spain. In the face of a warming planet, the impacts on human health are undeniable—and in many cases avoidable.
Heat waves have become the lethal climate phenomenon in Europe. Summer 2025 resulted in more than 3,800 deaths in Spain attributable to excess temperature, almost double the previous year. According to the Instituto de Salud Carlos III, 96 % of the deceased were aged over 65. More than half were over 85.
The impact has been felt throughout Europe. A study of 854 cities by the Imperial College London and the London School of Hygiene & Tropical Medicine concludes that climate change was responsible for 68 % of the 24,400 excess deaths recorded this summer from heat. The mean temperature in the analysed cities was 3.6 °C above the long-term average. The study notes that these cities only represent a portion of Europe’s population, so the real figure could be higher.
Breathing is harder too
Rising temperatures also degrade air quality. Heat promotes the formation of tropospheric ozone, which exacerbates respiratory diseases. In addition, pollen seasons are extending and highly allergenic species are increasing. Nearly 40 % of the European population suffers from pollen allergy—and that figure continues to grow.
In 2025, wildfires in Spain burned more than 350,000 hectares by October, with significant occurrences in Castilla-La Mancha, Catalonia, Andalusia and the Valencian, according to data from the Ministerio para la Transición Ecológica.
The episodes of smoke and poor air quality have had consequences for respiratory health, especially among older persons and those with chronic diseases. Multiple studies document a rise increases in medical consultations and hospitalisations due to smoke exposure in similar contexts.
Diseases that cross borders
Warming also enables insects and microbes to expand their geographic range. In 2024, autochthonous dengue cases were confirmed in Catalonia—six in total, all in Tarragona. Italy reported over 200 that same year. The Asian tiger mosquito, which transmits dengue, chikungunya and Zika, is already endemic across much of the Mediterranean basin.
The expansion of ticks is likewise causing a rise in the incidence of diseases such as viral encephalitis and Lyme disease. The West Nile virus infection has become a seasonal threat: in 2024, 1,436 autochthonous cases were reported in Europe, and Spain communicated several local outbreaks, prompting strengthened epidemiological surveillance in 2025.
Mental health is also deteriorating
Protracted exposure to extreme events such as wildfires, floods or forced displacement leaves a mark on mental health. Affected individuals show higher levels of anxiety, depression and post-traumatic stress. These impacts are not always visible, but they can last for years.
On top of that, there is growing concern about the lack of institutional response. Many young people express anguish over the environmental future and frustration at perceived inaction. So-called “eco-anxiety” is not a trend. It is an emotional reaction to a real threat that affects their life plans, their health and their wellbeing.
We need more
Spain has adaptation plans, early-warning systems and epidemiological surveillance. But the data indicate that this is not enough. Heat-related deaths are increasing. Climate-related infectious diseases are expanding. And the impacts on mental health are only beginning to be addressed.
Organisations such as the World Health Organization (WHO) and the European Environment Agency (EEA) have already warned that we face a health emergency. Public health needs resources, planning and justice. Because the effects of climate change are not neutral. They hit hardest those who already live in conditions of heightened vulnerability.
The climate crisis exacerbates pre-existing inequalities. Older persons, those with chronic disease, and those with socioeconomic disadvantages are paying the highest price. So too are those living in areas without shade, ventilation, or with limited access to medical services.
At Salud por Derecho we believe that defending health in the context of the climate crisis is a political responsibility. It is urgent to invest in prevention, adapt urban and rural environments, reinforce primary care and protect those most exposed.
Caring for the planet means caring for life. No health without climate justice.
