Viewed from a great distance in both space and time, the nighttime glow of inhabited areas on Earth is steadily increasing. However, the hidden variability within in this overall change has been demonstrated by a new analysis of satellite data undertaken by a research team from the University of Connecticut, in collaboration with NASA and researchers in the U.S. and Germany. “For the first time, daily satellite images were used for this purpose on a global scale,” says Professor Christopher Kyba, professor of nighttime light remote sensing at the Ruhr University Bochum, Germany, who participated in the study. The data confirm earlier studies that light emissions are increasing overall. However, the most important new finding is that fluctuations occur frequently, and are not solely attributable to major factors such as the COVID-19 lockdowns or the war in Ukraine. The researchers reported their findings in the April 8, 2026, issue of the journal Nature.