Saharan dust drifting into Europe has grown by up to 25% over nearly a decade, and it’s starting to cloud the continent’s bet on solar power

Europe has spent years cutting pollution from factories, traffic, and household heating.

Yet one growing source of airborne particles cannot be stopped at a smokestack because it begins thousands of miles away in the deserts of North Africa.

A major international analysis now finds that desert-dust pollution over Europe increased by roughly 10% to 25% between 2012 and 2021.

There is no reason to panic about a continent-wide solar crisis, but the trend is becoming harder to ignore as countries such as Spain depend more heavily on sunshine to run homes, businesses, and air conditioners during that sticky summer heat.

More dust, not necessarily more storms

An international team led by project leader Kaspar Dällenbach at the Paul Scherrer Institute assembled about 18,500 daily measurements from 103 rural and urban monitoring stations.

Working through the pan-European Clouds and Trace Gases Research Infrastructure (ACTRIS) research network, the researchers combined chemical observations, satellite information, land-use data, and a physical dust model with machine learning.

Machine learning is a form of artificial intelligence that learns patterns from large sets of examples.

In this case, it helped reconstruct daily ground-level dust concentrations across Europe, including smaller episodes that conventional models often miss.

Southern Europe averaged 5.3 micrograms of desert dust per cubic meter of air, compared with 2.1 in central and northern Europe.

For U.S. readers, that is about 4.1 micrograms in a cubic yard of air in the south and 1.6 micrograms in the same volume farther north.

Lead author Petros N. Vasilakos said the number of storms had not actually increased, but “they have become more intense,” meaning individual intrusions are carrying more dust into Europe.

Why solar panels lose power

Saharan dust affects photovoltaic panels in two ways.

Photovoltaic means that the modules convert sunlight directly into electricity, but suspended particles can scatter or block part of that sunlight before it reaches the glass.

Then comes “soiling,” the industry term for dirt that settles on a panel and acts like a dusty window until rain or cleaning removes it.

A separate Madrid rooftop study shows why dry weather matters.

Researchers measured losses of around 6% on low-tilt modules after 52 days without rain, while their models indicated that roughly 0.16 to 0.24 inches of rainfall was generally needed for effective natural cleaning.

That does not mean every calima event will cut production by 6%.

Losses depend on dust density, panel angle, wind, humidity, rainfall, and how long the surface remains dirty, so operators need local measurements rather than a single Europe-wide rule.

Spain has more at stake

Spain sits close to North Africa and lies directly in the path of many western Mediterranean dust flows.

The new analysis found that western southern Europe, including Spain, generally experiences its strongest seasonal dust concentrations in July and August, just when solar output and cooling demand can both be high.

That timing matters because solar power is no longer a side player in the Spanish grid.

According to Red Eléctrica’s 2025 electricity review, renewables supplied 56.6% of national generation when self-consumption was included, while solar photovoltaic power accounted for 18.4% of the mix before self-consumption was added.

A dusty forecast can therefore become an energy-planning issue, not merely a question of whether rooftop owners should wash their panels.

When expected solar generation falls, grid operators may need storage, flexible power plants, or other available generation to keep supply and demand balanced.

A small forecasting error spread across thousands of installations can become a much larger system problem.

Forecasts make the risk manageable

Spain already has experience with early warnings.

The Institute of Environmental Assessment and Water Research (IDAEA-CSIC) dust alert system, operated with the Centre for Energy, Environmental and Technological Research (CIEMAT) and the Ministry for the Ecological Transition since 2001, sends forecasts about 24 hours ahead to more than 250 recipients, including air-quality networks, hospitals, and allergy organizations.

The WMO Barcelona Dust Regional Center also publishes forecasts for the next 72 hours across North Africa, the Middle East, and Europe.

Energy companies can use the same advance notice to adjust output estimates, schedule cleaning when it makes economic sense, and prepare replacement generation if a major plume is expected.

Cleaning every time the sky looks hazy would waste labor and water.

Waiting too long can sacrifice electricity, so the useful question is not whether dust is coming, but how much will reach ground level and how much will stay on the modules.

That is where better forecasting earns its keep.

A longer warning from Alpine ice

The decade-long monitoring record was only part of the investigation.

Scientists also analyzed an ice core from Colle Gnifetti on the Swiss-Italian border, where layers of glacier ice preserve particles deposited over many generations.

That record indicated that desert-dust deposition increased by about 110% from preindustrial times through the industrial era, covering roughly the past 150 years.

The researchers linked the long-term rise mainly to increasing dryness and land degradation in North Africa, while recent year-to-year changes were strongly associated with shifting atmospheric circulation and the precise contribution from human-driven climate change remains unsettled.

The message for solar energy is practical, since Europe can keep expanding photovoltaic power if dust forecasts, maintenance plans, and grid models improve along with it.

The main study has been published in Nature.