From space, our planet appears to be more ocean than Earth. But despite the water covering 71% of the planet’s surface, more than half the world’s population endures extreme water scarcity for at least one month a year. And current estimates predict that by 2040, up to 20 more countries could be experiencing water shortages. Taken together, these bleak statistics raise a startling question: are we running out of clean water?
從太空來看,我們星球上的 海洋看起來比陸地還多。 但,儘管星球表面 有 71% 被水覆蓋, 世界人口超過一半以上, 一年至少有一個月 要容忍水極度匱乏的狀況。 目前的估計預測是, 到 2040 年, 高達二十個以上的國家 會遇到水短缺。 把這些不妙的統計數字放在一起, 就呈現出一個駭人的問題: 乾淨水要被我們用完了嗎?
Well yes, and no. At a planetary scale, Earth can’t run out of freshwater thanks to the water cycle, a system that continuously produces and recycles water, morphing it from vapour, to liquid, to ice as it circulates around the globe. So this isn’t really a question of how much water there is, but of how much of it is accessible to us. 97% of earth’s liquid is saltwater, too loaded with minerals for humans to drink or use in agriculture. Of the remaining 3% of potentially usable freshwater, more than two-thirds is frozen in ice caps and glaciers. That leaves less than 1% available for sustaining all life on Earth, spread across our planet in rivers, lakes, underground aquifers, ground ice and permafrost. It’s these sources of water that are being rapidly depleted by humans, but slowly replenished by rain and snowfall.
嗯,是,也不是。 在星球的層面上, 因為水循環的緣故, 地球不可能把淡水用光, 水循環是一個能持續 產生水並回收水的系統, 當水在全球循環時,將它從 蒸氣轉變為液體,再轉變為冰。 所以,問題並不是有多少水, 而是我們能夠取得多少水。 地球的液體中有 97% 是鹹水, 其中含有太多礦物,人類無法飲用, 也不能用在農業上。 剩下 3% 可能可以用的淡水中, 超過三分之二在冰帽 和冰河中結成冰。 那就只剩不到 1% 的水可以取用 來維持地球上所有的生命, 這些水散佈在地球各地的 河流、湖泊、地下蓄水層、 底冰,和永久凍土層中。 正在被人類快速 耗盡的是這些水源, 但由降雨和降雪 來補充的速度卻很慢。
And this limited supply isn’t distributed evenly around the globe. Diverse climates and geography provide some regions with more rainfall and natural water sources, while other areas have geographic features that make transporting water much more difficult. And supplying the infrastructure and energy it would take to move water across these regions is extremely expensive.
這有限的供應, 並沒有平均分佈在全球。 多樣化的氣候和地理, 讓一些地區降雨比較豐富, 天然水資源較充沛, 其他地區的地理特徵 則讓水的運輸十分困難。 若要將水從一個地區 移到另一個地區, 所需要的基礎設施 和能源是極昂貴的。
In many of these water-poor areas, as well as some with greater access to water, humanity is guzzling up the local water supply faster than it can be replenished. And when more quickly renewed sources can’t meet the demand, we start pumping it out of our finite underground reserves. Of Earth’s 37 major underground reservoirs, 21 are on track to be irreversibly emptied. So while it’s true that our planet isn’t actually losing water, we are depleting the water sources we rely on at an unsustainable pace.
在許多水貧乏的區域, 以及一些比較能取得水的區域, 人類揮霍當地水供應的速度 比水補充的速度還快。 當更多快速補充的源頭 無法滿足需求時, 我們就開始取用有限的地下水。 在地球的 37 個主要地下水庫中, 有 21 個將會被用盡, 且這是無法復元的。 所以,的確,我們的星球 其實並沒有損失水, 但是我們正在以不永續的步調, 耗盡我們仰賴的水來源。
This might seem surprising – after all, on average, people only drink about two liters of water a day. But water plays a hidden role in our daily lives, and in that same 24 hours, most people will actually consume an estimated 3000 liters of water. In fact, household water – which we use to drink, cook, and clean – accounts for only 3.6% of humanity’s water consumption. Another 4.4% goes to the wide range of factories which make the products we buy each day. But the remaining 92% of our water consumption is all spent on a single industry: agriculture.
這可能聽起來很驚人——畢竟, 平均來說,一個人一天 只會喝大約兩公升的水。 但在我們的日常生活中, 水還有一個隱藏的角色, 且在同樣的 24 小時中, 估計大部分的人其實 會消耗掉三千公升的水。 事實上,家庭用水——我們 飲用、煮菜、清洗用的水—— 只佔了人類水消耗的 3.6%。 另外 4.4% 用在各種不同的工廠, 用來製造我們每天購買的產品。 但剩下 92% 的水 都消耗在單一種產業中:農業。
Our farms drain the equivalent of 3.3 billion Olympic-sized swimming pools every year, all of it swallowed up by crops and livestock to feed Earth’s growing population. Agriculture currently covers 37% of Earth’s land area, posing the biggest threat to our regional water supplies. And yet, it’s also a necessity. So how do we limit agriculture’s thirst while still feeding those who rely on it?
每年,我們的農場用掉的水 等同 33 億個奧運大游泳池的水, 這些水全都被作物和牲畜吞沒了, 再拿來餵食地球上 不斷成長的人口。 目前地球上的土地面積, 有 37% 是用在農業上, 對於我們地區性的水供應 造成最大的威脅。 但,它也是必要的。 所以,我們要如何限制 農業的水需求, 同時仍然要能餵食仰賴農業的人?
Farmers are already finding ingenious ways to reduce their impact, like using special irrigation techniques to grow “more crop per drop”, and breeding new crops that are less thirsty. Other industries are following suit, adopting production processes that reuse and recycle water. On a personal level, reducing food waste is the first step to reducing water use, since one-third of the food that leaves farms is currently wasted or thrown away. You might also want to consider eating less water-intensive foods like shelled nuts and red meat. Adopting a vegetarian lifestyle could reduce up to one third of your water footprint. Our planet may never run out of water, but it doesn’t have to for individuals to go thirsty. Solving this local problem requires a global solution, and small day-to-day decisions can affect reservoirs around the world.
農夫已經在找一些很巧妙的方式 來減少農業對水的衝擊, 比如用特殊的灌溉技巧,來讓 「每滴水能種植的作物」更多, 並培育出比較不需要水的新作物。 其他產業則跟進, 採用能將水再利用和回收的製程。 就個人的層面來說,減少 用水的第一步是減少食物浪費, 因為目前,農場所產出的食物中 有三分之一被浪費掉或丟棄。 你可以考慮選擇購買 耗水較少的食物, 比如帶殼堅果和紅肉。 選擇吃素能夠將你的 水足跡減少三分之一。 地球的水可能不會用完, 但水不需要用完,局部的人 就可能會沒有飲用水了。 要解決這個局部的問題, 需要的是全球性的解決方案, 每天日常的小小決策都可能 會影響到世界的水庫。