Here’s how light pollution is affecting nature’s seasonal patterns

Research conducted across 3,000 sites in U.S. cities indicates that artificial light at night lengthens the growing season by advancing spring bud breaks and delaying autumn leaf changes. These shifts impact urban ecological services, potentially increasing vulnerability to frost and exacerbating respiratory health issues like asthma due to extended pollen seasons. While global urban light increased by approximately 1.8% annually between 2012 and 2016, some regions are mitigating these effects through LED street lighting and light shields.

• Artificial light at night advances the average date of spring leaf bud breaks by approximately nine days compared to sites without such lighting, and delays autumn leaf color changes by nearly six days across the lower 48 U.S. states. The magnitude of these shifts correlates with light intensity.
• The lengthening of the urban growing season has mixed implications: it may benefit urban farms and provide cooling shade earlier and later in the year, but it increases plant vulnerability to spring frost and creates timing mismatches with pollinators.
• Extended plant activity seasons can lead to longer pollen seasons, which are linked to increased health problems; specifically, a Maryland study noted a 17% rise in asthma hospitalizations during years with very early blooming.
• Global urban nighttime light increased by about 1.8% per year from 2012 to 2016, though some cities are countering this by adopting LED street lights and shields to reduce light pollution.

APA

Zhou, Y. (2022). Here’s how light pollution is affecting nature’s seasonal patterns. World Economic Forum. https://www.weforum.org/stories/energy-transition/light-pollution-environmental-climate-change-us-cities/

Chicago

Zhou, Yuyu. Here’s how light pollution is affecting nature’s seasonal patterns. World Economic Forum, 2022. https://www.weforum.org/stories/energy-transition/light-pollution-environmental-climate-change-us-cities/.

Wikipedia

{{cite report |last1=Zhou |first1=Yuyu |title=Here’s how light pollution is affecting nature’s seasonal patterns |publisher=World Economic Forum |date=18 July 2022 |url=https://www.weforum.org/stories/energy-transition/light-pollution-environmental-climate-change-us-cities/ |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{zhou2022heres, author = {Zhou, Yuyu}, title = {{Here’s how light pollution is affecting nature’s seasonal patterns}}, institution = {World Economic Forum}, year = {2022}, month = jul, url = {https://www.weforum.org/stories/energy-transition/light-pollution-environmental-climate-change-us-cities/}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }