光污染：光鮮外衣下的環境殺手

因為有光，都市的夜晚才更具活力和現代氣息。因為有光，人們才不那么畏懼黑暗。然而，人造光的濫用和不合理的照明造成了嚴重的光污染，昔日都市的靚麗風景如今卻成了披著光鮮外衣的環境殺手。盡管不少研究表明，光污染的危害不遜于水污染和空氣污染，但這一問題并沒有得到應有的關注。當你置身于炫目的人造光中時，你是否也曾懷念過那漆黑的夜空呢？

Darkness reigned at night until 200 years ago， when English inventors discovered how to make electrified carbon glow. The invention of the light bulb loosened the grip of darkness， gradually illuminating our world after sundown. Now， bright billboards， stadiums， parking lots， roadways and buildings cast a collective glow into our atmosphere， and offer enough ambient1） light to make land visible from space at night.

But with all of our modern technology allowing us brighter evenings， we pay a price： Artificially lit nights change our environment in many ways， including disrupting ecological dynamics and obscuring the landscape.

Living in around-the-clock2） light can harm our health， too： Scientists are associating artificial illumination at night with breast cancer. Diminishing dark skies also means cultural loss—constellations are a part of our heritage， and astronomers depend on darkened skies to study our universe. In a practical sense， light pollution wastes energy—and fossil fuels—as well as money， including taxpayers’ money.

Like global warming， light pollution extends to the far reaches of the globe and affects us all. And， as with our attempts to slow climate change， uniform efforts to illuminate more wisely are a gargantuan3） undertaking， and one of low priority in many regions. Still， scientists and advocates around the world are wising up4） to light pollution and figuring out how to solve this global quandary5）. With a problem as amorphous6） as light pollution， can our global village find a way to protect dark skies？

黑暗一度統治著夜晚，直到兩百年前，英國發明家才發現了用碳絲通電發光的方法。燈泡的發明打破了黑暗的籠罩，逐漸照亮日落之后的世界。如今，燈光明亮的廣告牌、體育場、停車場、公路和建筑物一齊將光束照向大氣層，這樣的地面照明足以讓人在夜間從太空看到陸地。

雖然種種現代科技賦予了我們更為明亮的夜晚，但我們也付出了代價：人工照亮的夜晚給我們的環境帶來諸多改變，包括生態系統動態受到破壞和景致遭到掩蓋。

生活在日夜不斷的明亮環境中也會損害我們的健康：科學家們正在研究夜間人工照明與乳腺癌之間的關聯。不斷減少的漆黑夜空也是一種文化損失—星座是人類遺產的一部分，而天文學家們要靠漆黑的夜空來研究宇宙。從實用的角度來說，光污染不僅浪費錢，包括納稅人的錢，還消耗能源及礦物燃料。

與全球變暖類似，光污染在全球波及的范圍很廣，影響著我們每一個人。如同我們為了減緩氣候變化所做的努力一樣，為了更明智地照明而齊心協力地付諸行動也是一項艱巨的任務，并且在許多地方都不受重視。盡管如此，世界各地的科學家和倡導者正意識到光污染問題的嚴重性，并努力尋找解決這一世界難題的辦法。對于光污染這種難以界定的問題，我們的地球村能否找到應對之策，留住黑夜？

How Light Is Wasted光是如何浪費的

Satellite maps of the world at night reveal continents outlined in white， with clearly defined， glaring metropolises. Much of Europe， the eastern US and eastern Asia appear thick with lights. “What you’re seeing is light directed upwards， which is foolish because the whole point of light is to help us get around，” says Peter Strasser， technical director at the International Dark-Sky Association （IDA）， the largest international non-profit that keeps tabs on7） light intensity. In contrast， wide swathes8） of Africa and Australia emit nearly no light.

From ground level， city streets are often bright enough for newspapers to be read after midnight. But in regions such as Yellowstone National Park in Wyoming， night brings a rare pitch darkness； lift your eyes and that darkness makes for9） optimal stargazing10）.

地球的夜間衛星圖顯示，陸地呈現出亮白的輪廓，燈光璀璨的大都市清晰可辨。歐洲大部、美國東部和亞洲東部的光亮顯得尤為密集。“你看到的都是向上射的燈光，這樣做很愚蠢，因為燈光的全部意義在于方便我們四處走動。”密切關注燈光強度問題的最大的國際性非營利組織國際黑暗天空協會的技術總監彼得·斯特拉瑟說。而相比之下，非洲和澳大利亞所在的大片地區幾乎不見一絲光亮。

從地面來看，午夜時分城市街道的燈光亮度常常足以用來閱讀報紙。但在美國懷俄明州黃石國家公園這樣的一些地區，夜幕帶來少見的漆黑，你可舉目仰望，這樣的黑夜最適合觀星。

Most Live in Darkness大多數人渾然不覺

Some two-thirds of the global population and 99 percent of the continental US and European Union live in areas where the night sky is considered polluted by light， according to a 2001 study by Italian astronomist Pierantonio Cinzano of the University of Padova. Much like urban river pollution， light pollution’s sources are hard to pinpoint. Millions of light bulbs contribute to a region’s atmospheric aura.

帕多瓦大學的意大利天文學家皮耶蘭托尼奧·沁扎諾于2001年開展的一項研究表明，美國本土和歐盟99%的人口、全球大約2/3的人口所生活地區的夜空都被認為受到了光污染。光污染的源頭難以明確，這一點和城市里的河流污染很像。某一地區上空的光芒是由億萬個燈泡形成的。

We light up roads and walkways at night to make our living spaces safer and to advertise our businesses. But too much light escapes to the sky， say dark-sky advocates. The worst culprits11） are poorly directed and poorly designed streetlights， such as the antique-style acorn lights that direct more light upward than downward. “It makes no sense to light up the undersides of airplanes when you’re trying to light up the street，” says Strasser. Other problem sources are powerful security and stadiums lights， floodlights12） that illuminate historic buildings and the far-reaching lights of shopping centers.

為了營造更安全的生活空間和進行商業廣告宣傳，我們照亮夜間的馬路和人行道。但倡導黑夜的人士表示，有太多的光都跑到了天上。最可惡的元兇是那些指向有問題、設計很糟糕的街燈，比如老式橡果狀街燈，這種燈將更多的光投向天空而非地面。“你的目的是要用燈照亮街道，結果卻照亮了飛機底部，這毫無意義。”斯特拉瑟說。其他污染源還包括高亮度的安全照明和體育場用燈，還有用于歷史建筑照明的泛光燈以及照明范圍很廣的購物中心燈。

The Damage of Artificial Light人造光的危害

Scientists who study light pollution say that in addition to wasting resources， excess artificial light harms wildlife—and us. Living things have evolved to take cues from light. Most famously， beachside lights attract newly hatched sea turtles—which by nature travel towards the moon over the water—to our inland human illuminations. Likewise， bright building lights disorient migrating birds， which then crash into the sides of buildings.

Brighter nights alter ecosystems in ways we’re still learning about， too. Light pollution in urban areas reduces algal13） consumption by zooplankton14） at night， because zooplankton need darkness to move about and consume surface algae， according to a study by Marianne Moore， associate professor at Wellesley College in Massachusetts. This suppression could contribute to algae blooms15）， known to worsen water quality.

研究光污染的科學家表示，除了浪費資源之外，過量的人造光還會危害野生動物以及人類。生物幾經進化，會從光中汲取信號。最廣為人知的是，新孵化出的海龜依照天性本應在水里朝著月亮游，而海邊的燈光卻吸引著它們游向內陸的人工照明設施。同樣，建筑物里明亮的燈光也會使候鳥迷失方向，從而撞到建筑墻面上。

更亮的夜晚也會給生態系統帶來改變，這些改變我們目前仍在研究。美國馬薩諸塞州衛斯理學院副教授瑪麗安·摩爾的一項研究表明，城市的光污染會減少浮游生物在夜間對水藻的捕食，因為浮游生物需要在黑暗中才能四處活動和捕食水面藻類。光污染抑制了浮游生物對水藻的捕食，這可能引發水華，我們都知道，水華會造成水質的惡化。

Breast Cancer Links光污染與乳腺癌

The hazy glow of light pollution harms humans too， by disrupting our circadian16） systems. “That’s how we evolved： by light and dark，” says Dr. Richard Stevens， a professor and cancer epidemiologist17） at the University of Connecticut Health Center. “We are designed for 12 hours of dark and 12 hours of light.” Our ancestors used fire， and then gas lights， which only produced dim light that would be extinguished by bedtime. Now， Stevens says， many of us are living in light throughout the night.

Our bodies produce a hormone in total darkness， melatonin18）， which helps to regulate the immune system and fight disease. In 2009， Stevens led an ecological study in Israel that revealed a strong correlation between nighttime light levels and incidences of breast cancer. Women living in the brightest areas （defined by the ability to read outdoors at midnight） had a 73 percent higher risk of developing breast cancer than those living in the darkest areas. Psychologically， intrusive lighting can cause poor sleep and annoyance. Light pollution also alters our dark-sky heritage on a global scale， to the point that many urban dwellers have never seen the Milky Way. Even suburban and rural areas are losing starry nights.

光污染那耀眼的光芒也會對人類造成危害，擾亂人們的生理節律系統。“我們就是這樣進化的：遵從晝夜節律，”美國康涅狄格大學健康中心的教授兼癌癥流行病學家理查德·史蒂文斯博士說，“我們人體天生就符合12小時黑夜、12小時白晝的節律。”我們的祖先曾經用火照明，后來又用煤氣燈，它們只是帶來些昏暗的光亮，睡前就會熄滅。而如今，史蒂文斯說，我們很多人都生活在徹夜通明的燈火中。

我們的身體會在完全漆黑的環境中產生一種叫做“褪黑素”的荷爾蒙，這種荷爾蒙有助于調節免疫系統，抵御疾病。2009年，史蒂文斯在以色列主持開展了一項生態學研究。研究顯示，夜晚的燈光強度和乳腺癌的發病率之間存在密切聯系。生活在最明亮地區（以午夜能在戶外閱讀為標準）的女性患乳腺癌的可能性要比那些生活在最黑暗地區的女性高出73%。從心理學的角度來說，刺眼的光會導致睡眠不佳、情緒煩躁。光污染還在全球范圍內改變了我們天空黑暗的傳統，以至于很多城市的居民從未見過銀河，甚至連郊區和鄉村也漸漸失去了群星璀璨的夜空。

Rising Crime Fears關于犯罪率上升的擔憂

Talk of dimming our light pollution makes some uneasy， since we rely on artificial light at night. “People are protective of light due to safety concerns and fear of crime，” says Emma Marrington， rural policy campaigner for the Campaign to Protect Rural England， so sometimes the mention of reducing light can raise criticism. However， an improperly lit home can actually aid criminals： Bright lights create sharp， contrasting shadows or glare where intruders can hide. Lighting can also help criminals see what they are doing and spotlight potential targets or escape routes. Illuminated areas can also attract social activity， especially among young people， creating opportunity for crime.

Dark-sky advocates say that smarter lighting practices will diminish light pollution and increase safety： Outdoor security lights should operate on motion sensors at a lower wattage， and only illuminate areas that need to be lit. Streetlights should be shielded to diffuse glare from the bulb and should only cast light downwards. Signs and advertisements should be lit from the top down rather than bottom up. Stadium and sports lights should be directed down， not up or out. For little-used walkways， short lights with red bulbs can shed light on paths； once eyes adjust to the dark， seeing is easy. Says Marrington： “We believe that this problem [light pollution] can be solved with the right amount and type of lighting， where it is needed and when it is needed.”

一說要減少光污染，就會有人惴惴不安，因為我們夜晚要依靠人造燈光。英格蘭鄉村保護運動的鄉村政策倡議人士艾瑪·馬林頓說：“人們愛護燈光是因為擔心安全問題，害怕犯罪行為。”所以，有時關于減少照明的提議會招致非議。但實際上，住宅照明不當反而有助于犯罪分子得逞：明亮的燈光會產生反差強烈的陰影或強光，給闖入者提供藏身之地。燈光還有助于犯罪分子在作案時看清自己的行動，鎖定潛在的作案目標或逃跑路線。燈光明亮的區域也是受人青睞的社交活動場所，對年輕人來說尤其如此，這給犯罪分子提供了可乘之機。

倡導黑夜的人士表示，更合理的照明措施將減少光污染，提高安全性。戶外安全照明應使用配備運動傳感器的低瓦數燈具，并且只照亮需要照明的區域。街燈應加裝防護罩，使燈光漫射并且只向地面投射光亮。標識牌和廣告牌應從頂部往下而非底部往上照明。體育場和運動場的照明方向也應朝下，而非朝上或朝外。對于極少使用的人行道，光線較短的紅色燈泡就能照亮道路。眼睛一旦適應了黑暗，看清物體并不困難。馬林頓說：“我們認為，在需要的時間、需要的地點采取適當強度和類型的照明能夠解決（光污染）這個問題。”

1.ambient [??mbi?nt] adj. （聲音、光線等）四周的，環繞的

2.around-the-clock：日夜不斷的

3.gargantuan [ɡɑ?（r）?ɡ?ntju?n] adj. 巨大的

4.wise up：意識到；想通；看透

5.quandary [?kw?nd?ri] n. 無所適從的窘境；左右為難的境地

6.amorphous [??m??（r）f?s] adj. 無明確方向（或目標）的

7.keep tabs on：密切注意……的動態

8.swathe [swe?e] n. （與兩旁區域有所區別的）長條地帶

9.make for：有利于

10.stargazing [?stɑ?（r）?ɡe?z??] n. 天體觀察

11.culprit [?k?lpr?t] n. 引起問題（或麻煩）的原因

12.floodlight [?fl?d?la?t] n. 泛光燈

13.algal [??lɡ?l] adj. 藻類的

14.zooplankton [?z?????pl??kt?n] n. [總稱]浮游生物

15.algae bloom：水華，是淡水水體中藻類大量繁殖，使得水體呈現藍色或綠色的一種自然生態現象。水華的頻繁出現會大量消耗水中的氧氣，威脅水中生物的生存，同時影響飲用水源和水產品安全。

16.circadian [s??（r）?ke?di?n] adj. [生]晝夜節律的，（24小時）生理節奏的

17.epidemiologist [?ep?di?mi??l?d??st] n. 流行病學家

18.melatonin [?mel??t??n?n] n. [生]褪黑素