Cities turn streetlights red to protect nocturnal ecosystems

[0:00] Today marks the final day of Dark Sky Week, which is hailed as a global celebration of the night [0:05] and a call for less light pollution. In some cities internationally, local governments are [0:11] trying to find a solution to lighting the night that can better serve critical wildlife ecosystems [0:16] and humans alike. Malcolm Brabant reports from Denmark. [0:22] It's dusk in Gladzaxa, a municipality north of Copenhagen that prides itself [0:27] on combining urban growth with environmental initiatives. [0:31] Gladzaxa was the first Danish local authority to install red street lighting [0:36] that helps reset the balance between human beings and the animal kingdom. [0:41] The council removed conventional white spectrum street lamps from this stretch of road [0:46] next to a large bat colony in the trees. [0:49] Artificial white light is hugely disruptive for a broad range of creatures. [0:53] For example, bees get a form of jet lag, frogs lose their libido, and bats find it difficult to catch food. [1:02] Red light enables bats to see in the dark, unlike white light, which blinds them. [1:07] This simple solution to restoring bats' night vision has been adopted in Metz in eastern France, [1:14] Worcestershire in the British Midlands, Germany, the Netherlands, Belgium, and it's spreading. [1:19] Every light source we put up changes some balances, moves things around, [1:24] makes it easier for some animals to find a mate, get food, and makes it harder for someone else. [1:32] Rune Brandt-Hermansson was one of the designers behind the red light project in Gladzaxa. [1:37] We need to take care and try to change and affect our surroundings as little as possible, [1:44] and a lot of lightning is actually there for no one's sake. [1:47] I'm not an advocate that we should not have lighting for humans. [1:51] I'm an advocate that we should try and have as little lighting as we can, [1:55] so we can offer more darkness for nature. [2:00] Biologists say that people need to recognize the importance of bats in the ecosystem. [2:05] They may resemble rats with wings, but they have a critical role to play in protecting human health. [2:11] We underestimate the importance of bats. [2:14] Mikael Steiner-Muller is a senior biologist with a Danish Sustainable Development Consultancy. [2:20] Bats are predators, and they eat half their weight in insects every night. [2:26] They're kind of a pest control and important part of keeping insects populations in kind of a natural balance and check. [2:33] The consequence of bats failing to feast on insects is that farmers are forced to use chemical pesticides on their crops. [2:41] Studies have shown that the toxins can contribute to cancer and other diseases in humans. [2:48] It's important to regulate how we affect the ecosystem, not only for the ecosystem itself, but for our health. [2:55] Steiner-Muller blends his biological knowledge with the design skills of lighting consultant Lise Dan Trapp [3:01] to create the most efficient illumination for a client's parking lot next to a sensitive wildlife habitat. [3:08] People are actually adapting to this new technology and this new type of light. [3:12] We've been used to having this very bright light during nights, and we have to actually change our mindset. [3:18] And people are, I think, really embracing this a lot. [3:22] People in Denmark really care about the nature. [3:25] If we can do something different, I think that people are really up for it. [3:27] Oense, Denmark's third-largest city, is the latest to install biodiversity lights. [3:34] This version, using orangey-red lamps, becomes softer and warmer as the night darkens, [3:40] aligning with the circadian rhythms, or internal body clocks, of nocturnal wildlife. [3:46] But as runner Michael Gruenbeck explains, some people find the darker pathways intimidating. [3:52] For those who have a fear of darkness, I think that this can feel unsafe. [3:57] Some people prefer more light. [3:58] Some don't. [3:59] It doesn't bother me. [4:02] Gladzakser sees itself as a role model for other cities around the world. [4:06] Switching to red lamps has proved to be a cost-effective way of addressing light pollution. [4:12] The system uses less power and requires less maintenance than conventional street lighting. [4:19] Sedal Benli is Gladzakser's mayor. [4:20] I hope that we can help inspire other municipalities to join the bandwagon here. [4:28] Because it is quite important that we think about sustainability, think about biodiversity [4:32] all the way around. [4:33] Because that is what we owe to future generations. [4:36] We owe it to our planet and to those we share this planet with. [4:40] Namely, to all living beings on this planet. [4:42] And consultant Rune Brand Hermansen predicts that improvements in lighting technology will [4:48] contribute more to the harmonious coexistence of humans and the animal kingdom. [4:54] We are at the brink of a lot of technological advancements that can actually make a difference [4:59] without it having a negative impact on humans. [5:02] Because we shouldn't change society. [5:05] I mean, we need lighting to do what we do. [5:08] There's no reason for us not to have our light and for nature to have the darkness or their light. [5:15] Conventional lighting accounts for approximately 5% of all global carbon dioxide emissions [5:20] and 15% of total global electricity consumption worldwide. [5:25] So, the experts say, switching to red streetlights could contribute to slowing climate change [5:32] as well as helping bats to maintain a healthy insect diet. [5:36] For the PBS NewsHour, I'm Malcolm Brabant in Gladsexer, Denmark.