Views: 1 Author: Site Editor Publish Time: 2026-04-30 Origin: Site
Satellite observations show that from 2014 to 2022, global nighttime lighting will increase at a rate of approximately 2% per year. Although the nights on Earth are getting brighter, the distribution of this trend is extremely uneven. The related research was published in Nature on April 8th.
Although the overall increase in global lighting has reached 16%, it does not mean that the lighting in all regions is increasing, "explained paper author Christopher Kyba from Ruhr University Bochum in Germany." We found that the global light radiation in areas with enhanced lighting increased by 34%, but was partially offset by an 18% decrease in radiation in other regions.”
These findings indicate that changes in nighttime lighting are more dynamic and regional than previously thought. The rapid urbanization process has made the nights in countries such as India brighter. In contrast, the amount of light radiation in some industrialized countries has decreased, which is usually related to the promotion of LED lighting and the introduction of policies to reduce light pollution.
Not all changes are gradual. After the outbreak of the conflict between Russia-Ukraine conflict, Ukraine's nighttime lighting decreased significantly. France has also experienced a significant decline, with nighttime brightness decreasing by 33%, as many cities turn off street lights after midnight to save energy and reduce light pollution.
Despite regional differences, the overall light radiation in Germany remains almost unchanged, "Kyba said." In areas where the lights become brighter, the light radiation increases by 8.9%, while in areas where the lights become darker, it decreases by 9.2%.”
Satellite monitoring data shows that the overall nighttime light radiation in Europe has decreased by 4%. But this decrease may not match people's actual perception, as satellites detect light in a different way than the human eye.
A major breakthrough in this study is the use of real-time nighttime data at full resolution. Previous analyses relied on monthly or annual averages, making it difficult to capture subtle short-term or local changes. No global analysis has ever used full resolution nighttime data, "Kyba emphasized.
The research team also used a new algorithm to correct the angle of satellite observation of the Earth. For example, when observed from a certain angle, residential areas tend to be brighter, while when observed directly above, densely populated city centers tend to be brighter. Incorporating these factors makes the monitoring of changes in light radiation more accurate.
This study used data provided by the visible light infrared imaging radiometer of the National Oceanic and Atmospheric Administration (NOAA) and NASA's Somi NPP, NOAA-20, and NOAA-21 satellites in the day and night bands. These satellites typically capture images from 1am to 4am in the local area and can cover almost all areas between latitude 70 ° N and latitude 60 ° S every night. Each pixel in the image represents approximately 0.5 square kilometers.
To ensure accuracy, researchers only counted artificial light sources and excluded natural phenomena such as wildfires and auroras detected by satellites.
Mastering the changes in nighttime lighting has practical significance. Light is the main source of electricity consumption at night, and light pollution can damage ecosystems, "Kyba said." Therefore, understanding the changing trends of both is crucial
As part of the European Space Agency's "Earth Explorer 13" mission, Kyba is leading the development of a new satellite specifically designed to monitor nighttime lighting, which can detect fainter light sources and provide higher resolution, thereby reducing the uncertainty of global lighting trends.
