World atlas highlights areas where light pollution can impact marine life, World News


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People who spend their lives in cities like Hong Kong, Shanghai, or Beijing might not be able to see the Milky Way with the naked eye in their lifetime.

Light pollution is simply a fact of modern city life, so much so that some people in China are willing to shell out over 10,000 yuan (2,000 Singapore dollars) to travel to less densely populated areas of the country and see landmarks. clear stars for the first time in their lives.

As our world becomes more populated and urbanized, scientists have started to study the impact of artificial lights on our health and the natural environment.

For example, the US city of Philadelphia was awakened in October 2020 when a major “collision event” resulted in the deaths of hundreds of birds because they were disoriented by the bad weather and drawn to the city by the lights. nocturnes, where they then flew into buildings, killing themselves.

As scientists continue to study the impact of light pollution on the sky, we know remarkably little about the impact of artificial lights on marine life, which is a problematic gap in our knowledge as the cities of today are very likely to be built near large bodies of water.

The only notable exception is sea turtles, where scientists have shown that light pollution disrupts their nesting habits.

In mid-December last year, a team of scientists from the UK and Israel took early corrective action by releasing a “global light pollution atlas” that shows where our lights are entering the oceans.

“Eight of the 10 largest megalopolises in the world are coastal, and they are booming. There is a ribbon development along the coastline which is essential for [the impact of light pollution] because you distribute your light over a large area, ”said Tim Smyth, scientific lead for marine biogeochemistry and observations at the Plymouth Marine Laboratory and co-author of the map.

By building a model around zooplankton, both light sensitive and essential to marine ecosystems, they created a map that allowed them and other scientists to identify hotspots where marine life could be. particularly vulnerable.

David McKee, another study author and physicist from the University of Strathclyde in Scotland, said: ‘What you are seeing is a growing awareness that the light we are emitting is eating away at the environment and that the potential impact is unknown at this time. .

“What we hope is that this atlas is a way to identify where the impact is most likely to be significant.”

The study found that many of the main emitters of artificial light are found in East Asia and Southeast Asia.

As these regions continue to urbanize, one problem has emerged as a major contributor to light pollution: LED lights.

Jason Pun, a senior lecturer in the Department of Physics at the University of Hong Kong, whose work includes monitoring light pollution, explained the reason.

“[The proliferation of LED lights] is a question that got lost in the conversation because this is a one-time global change in a generation. It is growing extremely fast and almost all newly installed lights are LED. “


LED lights emit a pronounced blue color and blue light diffuses more easily into the atmosphere, which is why our daytime skies are blue.

Pun said this was considered bad for two reasons. Firstly, it spreads in all directions so that people and animals outside of direct light cannot escape and are always negatively affected.

Second, evidence suggests that blue light is more harmful to animals, including humans, than other colors on the spectrum. A Harvard University study found that blue light disrupted participants’ circadian rhythm, increasing their blood sugar levels.

LED lights don’t need to be demonized, however. Experts have said that the carbon saving advantages of LED lights certainly outweigh the disadvantages, and with thoughtful implementation, LED lights can be installed in a way that reduces light pollution.

Two lighting-focused, US-based nonprofits, the International Dark-Sky Association (IDA) and the Illuminating Engineering Society, promote five principles of lighting to help fight light pollution.

Ashley Wilson, director of conservation at IDA, said businesses and individuals should consider the following:

  • The usefulness of light and whether it would be needed.
  • Could the light be better targeted to avoid spreading?
  • Use low light levels and watch out for reflections.
  • Can controls be installed such as timers, dimmers or motion detectors?
  • Limit the color, especially blue, that the light emits.

With this kind of forethought, along with government or private business incentives, light pollution does not need to become a form of uncontrollable human impact on the environment.

Pun said, “It’s not that hard to fix. The technology is already there; it has been adopted in some places but not everywhere. The reason [it is not widely adopted] are there any additional costs incurred, but compared to what you would have to do afterwards, the costs are very manageable. “

City governments around the world seem to be aware of the problems caused by light pollution, and while some might argue that the initiatives are insufficient, some changes are occurring.

In America, the city of Asheville in North Carolina passed an ordinance in 2018 requiring restaurants to turn off their exterior lights. A beach town north of Miami, Florida said in 2019 that beachfront businesses that don’t dim their lights at night could be fined US $ 1,000.

In Hong Kong, one of the world’s worst light polluters, the Department of Environmental Protection has launched an outdoor lighting charter that encourages companies to restrict the use of light between 11 p.m. and 7 a.m. in the morning. Participating companies are rewarded with public recognition from the government for their efforts.

Germany took action in 2020 to reduce its own light pollution, fearing it could affect the insect population.

Study authors McKee and Smyth suggest being wiser about how we light our night and be aware of overlighting.

“We just need to be smarter about how much light we’re using and where we’re directing it,” McKee said.

This article first appeared in South China Morning Post.


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