Clouds are thinning across much of Spain as European summers warm faster than the global average. In many parts of the continent, temperatures have risen more than two degrees Celsius since pre-industrial times. The Iberian Peninsula stands out as one of the regions most affected by heat, where high temperatures and soil drying create a feedback loop that keeps clouds scarce and evaporation lower.
A recent study from Stockholm University ties these shifts to human greenhouse gas emissions. The air over southern Europe has become drier, intensifying heatwaves and boosting fire risk along with other climate hazards.
Data cited by the United Nations Intergovernmental Panel on Climate Change (IPCC) show that land areas warm faster than the oceans, with an average mismatch of about 1.6 degrees Celsius on land versus 0.9 degrees Celsius at sea. This underscores the finite carbon budget and the pressure to curb emissions to keep global warming near 1.5 degrees Celsius above pre-industrial levels.
New findings published in the Journal of Geophysical Research Atmospheres indicate that the emissions budget for Europe during the April-September window is already strained. In fact, measurements reveal that summer warming in much of Europe has surpassed two degrees Celsius over the last forty years.
Paul Glantz, associate professor in the Department of Environmental Sciences at Stockholm University and lead author of the study, notes that climate change is amplifying heatwaves in Europe and, in turn, increasing wildfire risk, as demonstrated by fires in Southern Europe during the summer of 2022 (Stockholm University).
Few clouds in Spain
Across Southern Europe, especially the Iberian Peninsula, feedback loops from drier soils and reduced evaporation are driving warming and diminishing cloud cover. A thinner water vapor content in the air aligns with less cloud formation over much of Europe in recent decades, a trend observed in the study results and data analyses.
The investigation highlights a clear link: drying soils reduce evaporative cooling, which raises surface and lower-atmosphere temperatures. This chain reaction helps explain the observed drop in cloudiness and its regional expression in Spain.
As the study emphasizes, the loss of clouds in Southern Europe mirrors IPCC expectations that human impact on the greenhouse effect will leave drier areas even drier. The research also examines how aerosol particles—emitted during burning of fuels—interact with temperature changes. In Central and Eastern Europe, long-lived greenhouse gases like carbon dioxide are identified as a major driver of warming, while reductions in short-lived aerosol emissions from coal plants have moderated some fragmentary cooling effects. Nonetheless, overall warming continues to accelerate.
Analyses indicate that aerosols once masked a portion of warming caused by greenhouse gases, and as their atmospheric concentrations declined in the 1980s, temperatures rose more quickly. Carbon dioxide remains the principal long-term threat to climate stability, with implications for regions beyond Europe, including rapidly developing areas in Asia and other parts of the world.
The study cites a reference work for further context and emphasizes the need for sustained global action to address emissions and climate resilience. This body of evidence underscores the urgency of policies that cut greenhouse gases while supporting adaptation to changing weather patterns. The broader takeaway is clear: reducing fossil fuel use and transitioning to cleaner energy sources is essential for limiting future warmth and its cascading impacts.
For those following climate science, the findings add nuance to the conversation about regional variability, the role of atmospheric aerosols, and the rapid pace of change in fallible weather systems. The study demonstrates how even localized changes in cloudiness and evaporation can reflect larger global processes and the cumulative effect of human activity on the climate system. It also serves as a reminder that Europe is not insulated from the wider shifts underway in the atmosphere and oceans.
Further reading and data can be found in the study published by the Journal of Geophysical Research Atmospheres, with reviews and methodological details provided by Stockholm University researchers. The implications extend to policy-makers, educators, and communities planning for heat risk, water management, and wildfire preparedness in the coming years.
— End note: the research draws on field measurements, satellite observations, and climate-model simulations to piece together a coherent picture of how aerosols, evaporation, and soil moisture interact to shape regional climate dynamics.