Researchers led by Zhe Zhu analyzed more than a million NASA-processed satellite images from 2014–22 and found global nighttime lights rose 16% but were highly volatile. Sub‑Saharan Africa and Southeast Asia brightened while Europe dimmed 4% and U.S. rose 6%; changes were attributed to urbanization, electrification, efficiency policies, conflict.

Volatile satellite-observed nighttime lights reveal where electrification, urbanization, efficiency policies and conflict are changing energy use and ecological light exposure globally. In the medium term, planners, policymakers and environmental managers can likely use these signals to target infrastructure, conservation and humanitarian responses and to evaluate policy effects on light pollution and energy access.