Season 3 – Episode 5: Drowning in light – The hidden costs of light pollution

For our Season 3 finale of Light O’Clock, we dive into a timely and often overlooked issue: light pollution. Artificial light at night has become a constant in modern life — but what are the hidden consequences? Our guests, Barbara Harding, Travis Longcore and Karolina M. Zielińska-Dąbkowska, bring scientific insight into how nighttime light exposure may affect human health, including possible links to cancer, and how it disrupts wildlife, ecosystems, and natural rhythms. We also explore practical solutions: since we can’t simply switch off the lights, how can we use artificial light more responsibly to protect both ourselves and the environment? We explain the five principles for responsible outdoor lighting created by International DarkSky Association (now DarkSky International) and the Illuminating Engineering Society. Links and resources DarkSky International website: https://darksky.org/ Ecological light pollution: https://doi.org/10.1890/1540-9295(2004)002[0191:ELP]2.0.CO;2 Five principles for responsible outdoor lighting: https://darksky.org/resources/guides-and-how-tos/lighting-principles/ Outdoor artificial light and cardiometabolic risk: https://doi.org/10.1093/aje/kwae269 Artificial light at night and cancer risk: https://doi.org/10.1016/j.scitotenv.2024.177059 Timestamps (00:00) What is light pollution? (02:17) Light at night and circadian rhythms (05:18) Light at night and cancer risk (09:35) How light pollution is measured (16:11) What's the link between light at night exposure and disease risk? (19:00) Ecological light pollution (20:50) Effects of light pollution in animals: birds and turtles (26:00) Artificial light and animals' circadian rhythms (28:55) Light pollution changing predators-preys dynamics (32:30) Awareness towards light pollution in different countries (35:20) Why did we start to use artificial light in the first place? (40:30) What are the current lighting standards? (43:00) Different stakeholders involved in outdoor lighting (47:00) Five principles for responsible outdoor lighting (55:20) Wrap up and outro