Light pollution disrupts carbon cycle balance across continents

by Sophie Jenkins
London, UK (SPX) Nov 13, 2025

Artificial light at night (ALAN) is changing how ecosystems store and release carbon across large areas, research from Cranfield University shows. The study, published in Nature Climate Change, analyzes data from 86 carbon flux monitoring sites and satellite observations across North America and Europe.

The researchers found that increased nighttime lighting boosts ecosystem respiration, leading to higher atmospheric carbon dioxide output. However, this process does not result in an equivalent increase in photosynthesis, the mechanism by which plants absorb carbon. As a result, the carbon storage capacity of these systems declines.

Lead author Dr Alice Johnston explained, "Light pollution is one of humanity's most visible environmental changes, but its impacts are often hidden. This is a widespread issue that's changing how ecosystems function, disrupting energy flows, animal behaviour, habitats and natural patterns. Put simply, brighter nights lead to greater carbon release, which is bad news for our planet."

Co-author Professor Jim Harris added, "Around a quarter of Earth's land surface now experiences some level of artificial illumination at night. Our findings suggest that this growing footprint could subtly but significantly shift the global carbon balance if left unaddressed."

The team recommends that climate models should include the effects of ALAN. While artificial night lighting increases by about 2 percent each year globally, it still remains unaccounted for in many climate change projections. The researchers note that ALAN is easier to resolve than many environmental problems, with improved lighting design able to reduce the problem quickly.

Dr Johnston commented, "Unlike climate change, we could reduce light pollution almost overnight with better lighting design. Adopting dimmable, directional, and spectrally sensitive lighting technologies is an immediate and achievable improvement."

She also noted that since lighting accounts for about 15 percent of global electricity use and has documented impacts on human health, reducing light pollution would benefit the environment, energy use, and public health simultaneously.

The research used data from the FLUXNET2015 network and global night light datasets. The study was supported by the UK Natural Environment Research Council (NERC) grant NE/W003031/1.

Research Report:Widespread influence of artificial light at night on ecosystem metabolism