NASA Maps Show Shifting Patterns of Nighttime Artificial Light Worldwide

New maps from NASA, drawn from nearly a decade of data, reveal shifts in the use of artificial light around the world.

NASA researchers created the maps by analyzing data from the Black Marble program. That program uses a specialized sensor to capture low-light imagery of Earth at night. The data came from three satellites between 2014 and 2022.

Researchers had expected a gradual increase in artificial light at night over the years, NASA said in a news release. Instead, they found much more nuanced patterns of light radiance.

"The analysis portrays a world flickering with industrial booms and busts, construction, and blackouts, as well as more gradual shifts, such as policy-driven retrofits," NASA said.

Each location examined by the sensors showed several distinct shifts over the nine years. Radiance increased 34%, while dimming offset it by 18%, the researchers said. Both lighting and dimming markedly intensified over the past decade, they added in a study published in the journal Nature.

"This evidence of increasing volatility in human night-time activity provides an important dynamic dimension for understanding urban evolution, energy transitions, policy impacts and ecological consequences of rapidly changing illuminated nights," the researchers wrote.

In the United States, West Coast cities grew brighter as populations increased. East Coast areas saw more dimming, which researchers linked to energy-efficient lightbulbs and broader economic restructuring.

Nights grew brighter in China and northern India with urban development. Europe showed dimming from energy conservation measures, plus a sharp drop in 2022 after the war in Ukraine triggered a regional energy crisis.

"This global, high-resolution analysis ... refines and expands our understanding of how humanity is altering the night environment," the researchers wrote. "Our findings show that the human light footprint is not a universally expanding entity but a dynamic system, characterized by the pervasive coexistence of brightening and dimming."