"I have never ever seen anything
like this, obviously." "We’re having an earthquake, relax!" "There is a magnitude 6.6 earthquake!" In 1994 Los Angeles was hit by a strong earthquake. It caused
chaos on the streets and a blackout. "As you look out [of] your window it’s
probably pitch dark right now." During the blackout many people
called observatories and even 911. Not because the earth was shaking, but because
they saw a "giant silvery cloud" in the sky. That cloud was, in fact, the Milky Way --
countless stars they had never seen before. You maybe haven't heard much about it yet. But light pollution doesn’t merely conceal stars, it seriously affects our health and the environment. When the first light bulb was turned on in the
19th century, it marked a real revolution. Night suddenly became day. It’s great! With electric light we can travel, work, go out or party whatever the time of day. The pioneers might not have expected their
invention to take over the whole world. In fact, in many places electric
light has banished true darkness. "In terms of proportional changes to the
world, the introduction of this light into the night is one of the most dramatic
changes that we've made to the biosphere." This is Christopher Kyba, he researches artificial light emissions from cities and their impact. Today, more than 80 percent of the world’s
population no longer experiences dark skies. For example: nights are so
bright in Singapore that people can't adapt their vision for darkness. Today scientists are warning of the
dangers of artificial light at night. "It did mentally affect me and that's
when I decided to pursue this matter. This is Nilesh Desai, activist in India.
His goal: reduce night brightness. Scientists now consider artificial
light at night a form of pollution. "During the entire development of multicellular
organisms and plants and animals and vertebrates and then mammals and primates and humans -- during that whole time -- there was this constant signal coming from the environment. This is daytime.
This is nighttime. This is the lunar month. And in areas that had experienced
strong light pollution, that signal has been dramatically changed." Industrialization over the past century
has led to a surge in artificial illumination. "We see that most countries in the
world are becoming brighter." This has accelerated in recent
decades, particularly in Asian cities. All violet dots on this map show new light sources
installed in India between 2012 and 2016. There are various components of light pollution. There's glare -- that's when extremely
bright light causes visual discomfort. And clutter -- irritating
groups of bright lights. Light trespass -- when light falls
where it’s not needed or wanted. And skyglow -- when artificial light
brightens the night sky over cities. "It's just horrible. It is horrible.
It's a huge sky glow. You can just see the orange glow across the entire
Mumbai combined with a lot of air pollution." This is the view
from Nileshs’ apartment in Mumbai. He lives on the seventh floor with his
family and is literally in the spotlight. Lights from nearby streets and a stadium
shine directly into their apartment. "Lights used to be on until like 12 am
or sometimes till 3 am in the night and I used to get disturbed by
those lights, you know, bright lights coming into my room, my bedroom. And it definitely
impacted me because I could not sleep." Curtains and sleep masks failed
to improve the situation. So in 2018 he complained to the
authorities, claiming a right to darkness. At first they ignored him,
even though studies link artificial light to eye injuries, sleeplessness,
obesity and maybe even depression. Some studies of shift workers have indicated
that exposure to light at night could increase the risk of breast cancer. But why? "So there's a hormone that our brain makes called melatonin which
in mammals is a signal of darkness. And when we don't get that hormone,
when we don't produce that hormone because we're exposed to so much light
in our apartment or as a shift worker, then the whole working of this whole
biological clock system becomes problematic." Sleep, digestion and blood pressure are
regulated by this biological clock. And here two of the greatest light inventions
of recent decades come into play: LEDs and screens.
They are very bright and very efficient. And that comes at a price.
We may not be able to do anything about bright lights outside, but the lights we have
at home are often literally in our hands. The problem is not only
brightness, but also color. Blue light from phone displays, screens
and LEDs is similar to daylight. While light, in general, can suppress the
production of melatonin, blue light from screens and LEDs can do so more strongly.
That’s why experts at Harvard recommend not using bright screens or LED lights for
two to three hours before going to bed. Or switching to dimmer and
warmer shades of light. Light at night doesn't only threaten our health. "There is a tremendous change because the increase of brightness
at nighttime is new to evolution. This is Sibylle Schroer from the Leibniz Institute of Freshwater Ecology and Inland Fisheries in Berlin. She researches the impact of light on ecosystems. "Light is not neutral. Light has an effect." Corals, birds and many other species
of wildlife struggle when it’s light at night where it used to be dark.
Freshly hatched turtles should make their way into the sea. But lights near the shore
can mislead them. They head inland and die. Artificial light at night contributes
to the decline in insect populations. One study says the decline amounts to
100 billion every summer in Germany alone. Such light also contributes to a decrease
in nocturnal pollination activity. A UK study found that
where there's nighttime lighting trees bud earlier and
lose their leaves later than elsewhere. All these various effects on
different creatures and plants together affect the environment as a whole. "So predators can maybe hunt better
because they can see better. Others will stay in the dark
-- smaller species, for example -- and this disturbs the predator-prey relationships and changes whole ecosystems with this." With cheaper and more efficient light sources,
the world is getting brighter every year. The International Dark Sky Association estimates that one third of all outdoor lighting in the
US is wasted, fulfilling no purpose. As fossil fuels are still the main source
of energy, this contributes quite unnecessarily to air pollution and climate change. So what can we do as individuals? It might sound obvious, but turn on
lights only when and where you need it. And then turn it off again. Or let a
motion sensor turn it on and off for you. Use lampshades, for instance,
to block unwanted stray light. Use lights with a warmer tone – they
can be just as efficient. And lower the intensity when
possible. Dimming is the magic word here. Entire cities, even entire countries
can adopt such solutions. France for example has banned sky beams,
and in some places set times when lights in public spaces have to be dimmed or switched off,
as well as capping the brightness of lamps in ecologically sensitive areas. „I am afraid that people don't realize
this is a serious issue and there need to be rules and regulations as to how
we install lights and where we install lights.“ After protests from citizens like Nilesh Desai, Mumbai politicians have signaled they are
open to reducing light pollution. They have called on the Indian Ministry
of Environment to implement laws. Nilesh Desai hopes it won't take a blackout
for the people of Mumbai to see the Milky Way -- one day, or rather one night.
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