• Uneven changes in nighttime light levels emerge between urban and industrial regions
• Satellite data shows global expansion of artificial lighting with clear regional disparities

New satellite observations show that artificial light at night is steadily increasing worldwide, but the trend is far from uniform, with sharp contrasts emerging between countries and regions.

According to analysis of data from NASA’s VIIRS nighttime monitoring system, global artificial lighting has risen by around 2% annually, reflecting ongoing urban expansion and industrial development in many parts of the world.

However, researchers note that the overall picture masks significant divergence between regions. Areas experiencing growth in night-time brightness recorded a 34% increase in emissions, while others saw consumption fall by about 18%, partially offsetting the global total.

The study highlights rapid urban growth in countries such as China and India as key drivers behind rising light levels, while several industrialized nations have recorded noticeable declines, largely due to the transition to energy-efficient LED lighting and policies aimed at reducing light pollution.

France saw a sharp 33% drop in nighttime brightness after many cities began switching off public lighting after midnight in an effort to cut energy use and limit light pollution.

In Germany, light emissions remained broadly stable overall, though regional differences persisted, with some areas recording increases of 8.9% while others fell by around 9.2%.

Across Europe, satellite measurements show an overall decline of 4% in nighttime lighting. However, researchers caution that this does not necessarily match human perception on the ground, due to differences between satellite sensitivity and the human eye.

The study is the first of its kind to use high-resolution daily global night-time data, offering a more detailed view than previous research based on monthly or annual averages.

Researchers also applied correction algorithms to account for satellite viewing angles, which can distort brightness readings in dense urban areas.

They warn that artificial lighting remains one of the largest sources of nighttime electricity consumption and contributes significantly to light pollution, which can disrupt ecosystems and human environments.

The findings come as scientists continue to develop new satellite tools dedicated specifically to monitoring nighttime light. A proposed European mission aims to improve detection of faint light sources and provide more precise global coverage.

Researchers note that while the United States and China already operate multiple monitoring satellites, Europe currently lacks a dedicated system for tracking artificial light at night.