industrial civilization

Caterpillars And Light Pollution | Earth Wise

May 3, 2023 By EarthWise Leave a Comment

Most of us are familiar with air pollution, water pollution, soil pollution, and even noise pollution. But it turns out that light can be a pollutant as well, and it’s a consequence of industrial civilization. In fact, nighttime light pollution now covers approximately 23% of the globe and over 80% of inhabited regions.

Light pollution affects more than just our view of the stars. For example, light pollution can alter our circadian rhythm, disrupting our sleep cycle. In nature, light pollution can kill baby turtles by causing them to head inland instead of into the ocean, can cause birds to migrate during the wrong season, and can deter nighttime pollinators like bats. And those are just a few of the examples.

According to new research from scientists at Cornell University, moderate levels of artificial light at night – like a porch light – attract caterpillar predators and reduce the chance that caterpillars grow up to become moths.

In the study, which was recently published in the journal Proceedings of the Royal Society B: Biological Sciences, the researchers placed 552 lifelike caterpillar replicas made of soft clay in a forest to measure predation rates compared to a control group. They found that predation rates on clay caterpillars and the abundance of arthropod predators were significantly higher on the artificial light at night treatment plots. In fact, of the 552 clay caterpillars deployed and glued to leaves to look authentic, 521 models were recovered and 249 of them- or 47.8% – showed predatory marks from arthropods during the summer-long nighttime study.

In addition to light pollution, caterpillars also face major threats from habitat loss, pollution, invasive species, and climate change.

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Artificial light at night aids caterpillar predators

Photo, posted July 23, 2020, courtesy of Judy Gallagher via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Global Light Pollution

October 14, 2021 By EarthWise 1 Comment

Light pollution is excessive or obtrusive artificial light. It’s a consequence of industrial civilization. Too much artificial light can cause a host of problems, including disrupting ecosystems, causing adverse health effects, and wasting energy.

According to a new study led by researchers from the University of Exeter in the U.K., global light pollution has increased by at least 49% over 25 years. But this figure only includes light visible via satellites. Scientists estimate that the true increase may be significantly higher – up to 270% more globally.

That’s because there is a hidden impact of LED technology that isn’t accounted for in the satellite data. LEDs emit more blue light than previous lighting technologies, but satellite sensors fail to pick up this blue light. This leads to a large underestimate of global light pollution.

The researchers examined light pollution from 1992 to 2017. They found persistently increasing light pollution in Asia, South America, Oceania and Africa. In Europe, detected light increased until around 2010, after which it leveled off. In North America, artificial light appears to be on the decline. However, the researchers point out that the satellites inability to detect blue light of LEDs means that light pollution has likely actually increased in most locations.

Light pollution has widespread impacts on both animals and plants. For example, light pollution can confuse the migratory patterns of animals and change predator-prey relationships. It’s also been shown to cause trees to bud earlier in spring.

While there’s no off switch for the planet, there are ways that we could reduce the amount of light drastically with little impact on our lives.

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Rapid increase in global light pollution

Photo, posted November 2, 2008, courtesy of Timothy Tsui via Flickr.

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Artificial Light And Nature | Earth Wise

December 4, 2020 By EarthWise Leave a Comment

Most of us are familiar with air pollution, water pollution, soil pollution, and noise pollution. But it turns out that light can also be a pollutant as well.

Light pollution is a consequence of industrial civilization. Sources of light pollution include building interior and exterior lighting, advertising billboards, factories, commercial properties, streetlights, and sporting venues.

According to findings in a new report from the University of Exeter, artificial nighttime lighting has a wide range of effects across the natural world and should be limited wherever possible. The research team analyzed more than 100 studies and found that artificial lighting has widespread impacts on both animals and plants.

In the study, which was funded by the Natural Environment Research Council in the U.K., researchers consistently found changes to animals’ bodies and behavior as a result of artificial lighting. In particular, levels of the sleep cycle-regulating hormone melatonin were reduced by exposure to artificial lighting at night in all animal species studied.

Exposure to artificial nighttime lighting also affected the timing of animals’ activities. For rodents, which are largely nocturnal, the duration of activity was often reduced by exposure to nighttime lighting. On the other hand, for diurnal birds, exposure to nighttime lighting led to an extension of the duration of their activities.

Previous studies have found other wide-ranging impacts of nighttime lighting, from reducing pollination by insects to trees budding earlier in spring.

Artificial nighttime lighting is human driven and very disruptive to the natural world. While there’s no off switch for the planet, we could reduce the amount of light pollution drastically with no impact on our lives.

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Artificial night lighting has widespread impacts on nature

Photo, posted July 29, 2017, courtesy of spacedust2019 via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.