Great Lakes Environmental Assessment and Mapping Project

Light pollution

Light pollution, also called photopollution, is excessive or obtrusive artificial light. Due to human activity, light pollution is especially pronounced in near shore areas of high population density. 

Impacts of light pollution

Excessive night lighting can have a number of impacts on aquatic and terrestrial species.

  • Disrupts fish foraging and reproductive behavior
  • Disrupts vertical migration of zooplankton (a phenomenon in which zooplankton migrate to shallow waters by night to feed on algae and retreat to deeper waters during the day to avoid visually feeding fish).
  • Interfere with navigation of bird migration leading to increased avian mortality

Several Great Lakes cities, including Milwaukee, Chicago, Detroit, Cleveland, and Toronto have fatal light awareness programs and are making efforts to extinguish decorative lighting in tall buildings.


Mapping light pollution as a Great Lakes stressor

We extracted the data layer for light pollution (“Lights at Night”) from the National Oceanic and Atmospheric Administration (NOAA) National Geophysical Data Center (NGDC) website. The data file represents a cloud-free composite made with Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) data.

This data source shows a decline in light intensity with increasing distance from light sources and results in near-total light attenuation by about 45 km offshore.