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Artificial Light at Night: State of the Science 2022 Report

by John Barentine
Dark Sky Consulting, LLC


To confront problems effectively, we must understand them. And to tackle the problem of light pollution around the world, we must become familiar with the knowns and the unknowns of the subject.

In support of that goal, today the International Dark-Sky Association (IDA) releases the “Artificial Light at Night: State of the Science 2022” (PDF) report. It’s a high-level overview of the best of our scientific understanding of how artificial light at night affects the nighttime environment. It finds the world transformed by electric light in less than 150 years since its introduction.

Our goal in issuing this report is to empower dark-sky advocates and the public with reliable, factual, understandable information about light pollution. “State Of The Science 2022” condenses the current scientific consensus on how artificial light affects seven key topics:

  1. The night sky
  2. Wildlife and ecology
  3. Human health
  4. Public safety
  5. Energy use and climate change
  6. Social justice
  7. The emerging threat from light pollution caused by objects orbiting the Earth

Where gaps exist in our knowledge, we highlight them as targets of future research.

The report is an outgrowth of the Artificial Light at Night Research Literature Database (ALAN DB). IDA helped establish this resource in 2014, and it now lists over 3,500 scientific papers on the subject. We combed through the contents of the database to find the most important among them, which we cite in a detailed bibliography at the end of the report. The resulting report was externally reviewed by subject matter experts, whom we thank for their comments that helped improve the final product.

We use illustrations from the papers we cite to make certain points clearer. Also, we wrote the report in language that avoids jargon, to make the contents understandable to more readers. The statements within the report, especially the “Headlines” that summarize the seven key topics, can be adapted for use as talking points in letters and presentations. We hope this makes the report accessible so advocates can incorporate more scientific results into their light-pollution messaging. Additionally, the report is free to download and distribute to target audiences and may even be used as a “leave behind” item for elected officials and their staff when considering relevant and prominent science to inform their policies.

For a closer look at how and why IDA created this report, click here to watch the March 2022 Advocates Meeting presented by Dr. John Barentine.

Scientific interest in light pollution is surging, and the number of scientific papers on the subject published each year is now three times higher than it was a decade ago. Researchers make new discoveries and collect data supporting earlier conclusions. The landscape of light pollution research changes often. As such, we consider this report a “living document” that will be updated in the future to account for further developments in the various fields of artificial light at night research.

Download the German translation of the Report, courtesy of Lukas Schuler.