Development Under Scrutiny
The iconic Cologne Cathedral, a UNESCO World Heritage Site, has undergone a significant transformation with the installation of new LED lighting. Surrounded by construction sites, dilapidated museums, and chaotic street furniture, the cathedral now shines brightly at night, attracting tourists and criticism alike.
The LED lighting concept, which took three years to implement, aims for "plastic, precise, and pinpoint accentuation." However, concerns have been raised about its impact on the cathedral's animal inhabitants.
Warm white lighting, such as the 3000 Kelvin used at the cathedral, can interfere with the natural behaviors of nocturnal animals by disrupting their circadian rhythms. This might affect the feeding, breeding, and migratory patterns of birds and other wildlife. The bright light can also cause visual pollution, making it difficult for nocturnal animals to navigate and find food, and habitat disruption, potentially leading to changes in local biodiversity.
To mitigate these effects, several strategies can be employed. These include using wildlife-friendly lighting, timing and dimming, and conservation efforts. Shifting to cooler or warmer light tones that are less disruptive to wildlife, such as 2700 Kelvin or even lower, can help reduce the impact on animals. Directing lights downward or using shielded fixtures to reduce glare and spillage into the sky is another solution.
Timing and dimming strategies include turning off or dimming lights during peak nocturnal activity hours and implementing smart lighting systems that adjust brightness based on the time of day and ambient light levels. Conservation efforts include protecting and restoring natural habitats around the cathedral to maintain biodiversity and educating visitors and local communities about the importance of reducing light pollution and its impact on wildlife.
The cathedral chapter states that it wants to keep light pollution at the cathedral as low as possible and protect it as a habitat and biotope. Despite this, the new LED technology results in a reduction in power consumption and light amount by almost a quarter compared to the previous lighting. The new technology also allows the lighting to be dimmed and the color temperature to be adjusted.
However, critics argue that the current 3000 Kelvin light color attracts insects, causing them to exhaust themselves and die from exhaustion when attracted to the new lighting. Nature conservation associations have criticised the illumination of the Cologne Cathedral due to light pollution.
Cologne has a master plan for light since 2020, but the topic of light pollution and its ecological effects is only touched upon on the side. The new LED lighting sets standards in terms of sustainability, nature conservation, and light emission-friendly design.
In 2014, biologists from Cologne University drew attention to the ecological diversity at the Cologne Cathedral. Many animals, as detailed in "The Ecology of Cologne Cathedral" by Iris Güthner and Bruno Kremer, live at the cathedral. As tourists navigate through these conditions to admire the Cologne Cathedral, it is hoped that the responsible parties will work towards achieving a reduction in light intensity and color temperature to ensure the preservation of this unique ecosystem.
- In an effort to protect the local wildlife, strategies such as using wildlife-friendly lighting, timing and dimming, and conservation efforts should be considered for the Cologne Cathedral's LED lighting.
- Shifting to cooler light tones, like 2700 Kelvin or even lower, and directing lights downward or using shielded fixtures can help minimize disruptions to nocturnal animals caused by the new lighting.
- The new LED technology, while reducing power consumption and light amount by almost a quarter compared to the previous lighting, has been criticized for attracting insects and causing them to exhaust themselves.
- Nature conservation associations have criticized the illumination of the Cologne Cathedral due to light pollution, and it is important for tourists and local communities to be educated about the impact on wildlife and the need for reducing light pollution.
