Dirty sky, less sunlight: How pollution steals our energy

The sunshine we see every day might look the same, but research shows the amount of light hitting our planet can change over long time spans. These changes occur in patterns that can affect climate, energy production, and day-to-day life for many people.

Scientists report that these patterns include periods of less sunlight, or “dimming,” and times of rebound, referred to as “brightening.”

Martin Wild of the Institute for Atmospheric and Climate Science, Swiss Federal Institute of Technology (ETH Zürich) is one of the researchers examining why these phases happen and how they may impact human life.

Sunlight changes over decades

Some of the changes come from aerosols, which are tiny particles in the air that can scatter or block sunlight. When pollution levels get higher, those particles can intercept more sunlight before it reaches the surface. This leads to lower light levels in many regions.

“The amount of sunlight – which is solar radiative energy – we receive at the Earth’s surface is not necessarily stable over the years but can undergo substantial decadal variations,” said Wild.

Cutting pollution has led to increasing sunlight in some places, but the degree of recovery is not the same everywhere.

Sunlight recovery and energy production

Scientists have paid extra attention to China. Reduced pollution can restore past sunshine levels and possibly boost photovoltaic power generation. 

“If China fully recovers from the dimming phase and reverts to the clean atmosphere levels of the 1960s, the country could make substantial gains in solar power production,” said Wild. This matters because more light hitting panels can mean more energy for millions of homes and businesses.

Observations point to shifts in energy coming from the sun over spans of ten years or more, also called decadal cycles. Such findings are drawn from surface-based measurements and satellite data, though each set of data comes with its own challenges.

Sunlight affects weather and energy

Light changes influence crops, temperature levels, and water evaporation. Some regions might see cooler days if pollution shades them, while others may notice shifts in rainfall patterns. A single percentage point dip in solar energy could affect how farmers plan their growing seasons.

“These decadal changes of dimming and brightening in the available solar energy are not only crucial for various aspects of climate and environmental change, but are also of significant importance for resource assessments in the rapidly growing sector of solar power production,” said Wild.

People might also face rising energy costs or lower crop yields when light levels decline.

Urgent need for solutions

Some scientists use advanced computer models to fill gaps in places where sunlight measurements are not recorded. Others monitor chemical emissions that can cut sunlight on its way down.

More collaboration could refine data collection so that researchers can give clearer predictions to policymakers and industries.

Insights from these studies hint that cutting air pollution and tracking how nature itself affects clouds hold promise for stabilizing future light levels. Further sunlight monitoring, paired with data on emissions, is seen as a crucial step for protecting and expanding solar energy options.

Tracking sunlight helps climate planning

Efforts to gather accurate data over many years help us see when light levels drop or rise. That information is especially valuable for people who build large-scale solar plants, since they rely on a steady supply of sunlight.

Industries need reliable expectations of how much power they can produce in any given year, and local communities want to know if weather patterns might shift.

Better measuring equipment, placed in more locations, could build a deeper understanding of how sunlight changes over time. Having these records is key for everyone from electric grid planners to local farmers. It can guide decisions about investing in new technologies or adjusting cropping schedules.

Clean air, sunlight, and energy costs

These shifting light levels do not always make headlines, but they underscore the careful balance between air quality and the sun’s energy at ground level.

Researchers continue refining their data, looking for signals to warn if light dips are around the corner. Work is ongoing to see what happens under different pollution scenarios.

The potential for healthier air and better solar power output is significant. As more nations adopt cleaner energy sources, these sunlight changes carry bigger economic weight. Reducing aerosol emissions could unlock added benefits for power grids and agriculture, which may be vital to thriving cities and rural areas.

The study is published in the journal Advances in Atmospheric Sciences.

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