Are we running out of clean water? - Balsher Singh Sidhu

944,677 views ・ 2018-12-06

TED-Ed


Please double-click on the English subtitles below to play the video.

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From space, our planet appears to be more ocean than Earth.
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But despite the water covering 71% of the planet’s surface,
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more than half the world’s population endures extreme water scarcity
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for at least one month a year.
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And current estimates predict that by 2040,
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up to 20 more countries could be experiencing water shortages.
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Taken together, these bleak statistics raise a startling question:
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are we running out of clean water?
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Well yes, and no.
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At a planetary scale, Earth can’t run out of freshwater thanks to the water cycle,
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a system that continuously produces and recycles water,
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morphing it from vapour, to liquid, to ice as it circulates around the globe.
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So this isn’t really a question of how much water there is,
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but of how much of it is accessible to us.
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97% of earth’s liquid is saltwater,
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too loaded with minerals for humans to drink or use in agriculture.
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Of the remaining 3% of potentially usable freshwater,
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more than two-thirds is frozen in ice caps and glaciers.
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That leaves less than 1% available for sustaining all life on Earth,
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spread across our planet in rivers, lakes,
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underground aquifers, ground ice and permafrost.
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It’s these sources of water that are being rapidly depleted by humans,
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but slowly replenished by rain and snowfall.
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And this limited supply isn’t distributed evenly around the globe.
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Diverse climates and geography provide some regions
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with more rainfall and natural water sources, while other areas have geographic features
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that make transporting water much more difficult.
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And supplying the infrastructure and energy it would take
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to move water across these regions is extremely expensive.
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In many of these water-poor areas, as well as some with greater access to water,
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humanity is guzzling up the local water supply faster than it can be replenished.
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And when more quickly renewed sources can’t meet the demand,
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we start pumping it out of our finite underground reserves.
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Of Earth’s 37 major underground reservoirs, 21 are on track to be irreversibly emptied.
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So while it’s true that our planet isn’t actually losing water,
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we are depleting the water sources we rely on at an unsustainable pace.
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This might seem surprising –
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after all, on average, people only drink about two liters of water a day.
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But water plays a hidden role in our daily lives, and in that same 24 hours,
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most people will actually consume an estimated 3000 liters of water.
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In fact, household water – which we use to drink, cook, and clean –
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accounts for only 3.6% of humanity’s water consumption.
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Another 4.4% goes to the wide range of factories
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which make the products we buy each day.
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But the remaining 92% of our water consumption is all spent on a single industry:
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agriculture.
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Our farms drain the equivalent of 3.3 billion
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Olympic-sized swimming pools every year,
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all of it swallowed up by crops and livestock
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to feed Earth’s growing population.
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Agriculture currently covers 37% of Earth’s land area,
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posing the biggest threat to our regional water supplies.
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And yet, it’s also a necessity.
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So how do we limit agriculture’s thirst while still feeding those who rely on it?
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Farmers are already finding ingenious ways to reduce their impact,
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like using special irrigation techniques to grow “more crop per drop”,
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and breeding new crops that are less thirsty.
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Other industries are following suit,
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adopting production processes that reuse and recycle water.
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On a personal level, reducing food waste is the first step to reducing water use,
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since one-third of the food that leaves farms is currently wasted or thrown away.
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You might also want to consider eating less water-intensive foods
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like shelled nuts and red meat.
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Adopting a vegetarian lifestyle could reduce
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up to one third of your water footprint.
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Our planet may never run out of water,
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but it doesn’t have to for individuals to go thirsty.
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Solving this local problem requires a global solution,
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and small day-to-day decisions can affect reservoirs around the world.
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