Overview

• Analysis of satellite data from 2014–2020 across 428 major northern hemisphere cities shows urban vegetation phases start 12.6 days earlier and end 11.2 days later than in rural areas.
• Average urban nighttime light intensity increased by about 10 percent over the past decade, with private window lighting contributing most of the after-midnight glow.
• Researchers found that artificial illumination has a stronger effect on plant phenology than the urban heat island warming.
• Prolonged growth periods may heighten early spring and late autumn frost damage risks and disrupt synchrony between plants and their pollinators.
• Scientists warn that the rise of LED lighting and higher water demands from lengthened growth cycles require sustainable light management in city planning.