What If All the Sea Water Becomes Fresh Water?
What if we didn’t have to worry about water consumption?
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00:00 Where do you go to quench your thirst?
00:07 The kitchen sink?
00:09 The local bar?
00:10 The mineral-rich springs of Bergamo, Italy?
00:13 In the 21st century,
00:15 you don't have to go that far for fresh water.
00:17 But still, supply is running out.
00:20 What if we didn't have to worry about water consumption?
00:24 What if you could drink and shower as much as you wanted?
00:28 What if a trip to the well and a trip to the beach were one and the same?
00:32 You might give a lot for those privileges.
00:35 But how much would it really cost?
00:38 This is WHAT IF,
00:39 and here's what would happen if all seawater became fresh water.
00:44 The first big question we have to ask is,
00:47 why is the ocean so salty to begin with?
00:50 Well, it wasn't always like that.
00:52 About 3.8 billion years ago,
00:54 Earth's surface had finally cooled to the point that water vapor turned to liquid.
00:59 No salt added.
01:01 That's right, a really, really long time ago,
01:03 the oceans were fresh water.
01:05 But that wasn't going to last.
01:07 Whenever it rains,
01:08 carbon dioxide from the air dissolves into the falling water.
01:12 This makes the rain slightly acidic,
01:14 and when it falls, it causes rocks to erode.
01:17 From there, rainwater slides towards nearby rivers and streams,
01:21 taking loose salt and minerals along with it.
01:24 From there, this runoff flows from rivers into the ocean.
01:28 Add to that any additional salt and minerals
01:30 that would be expelled from hydrothermal vents or submarine volcanoes,
01:34 and then consider that this whole process
01:36 has been recurring more or less consistently for 3.8 billion years.
01:40 That's a lot of salt.
01:42 In fact, there's so much salt in the ocean
01:44 that if you spread it evenly across all the land on Earth,
01:48 it would amount to one towering layer of salt that's 40 stories tall.
01:52 97% of all the water on Earth is saline,
01:56 and we've got to assume it's for a reason.
01:58 So what would our world look like if we took the salt out of the sea?
02:02 Freshwater oceans sure do sound like a godsend.
02:05 Right now, it's predicted that a third of the world
02:08 will be facing chronic water shortages by 2025.
02:12 At our current rate of consumption,
02:13 the global demand for fresh water doubles every 20 years.
02:17 So maybe freshwater oceans would actually yield a good outcome this time?
02:21 Nope.
02:22 A sea without salt would decimate marine life
02:25 and dramatically affect our weather and temperatures,
02:28 making human life on Earth very difficult, if not impossible.
02:31 There are roughly 228,450 species in the ocean,
02:36 and as many as 2 million more to be discovered.
02:39 But if the ocean were to become desalinated, we'd never find them.
02:42 Saltwater fish and other ocean creatures
02:45 evolved to be able to drink saltwater to stay hydrated,
02:48 and get rid of excess salt.
02:50 Not all sea creatures do this the same way,
02:51 but being able to pump out excess salt is crucial to surviving in the ocean.
02:56 Some species, like salmon, have adapted to tolerate freshwater and saltwater.
03:01 But for the most part, all saltwater species would perish.
03:05 This includes underwater algae, which, believe it or not,
03:08 accounts for half the photosynthesis that occurs on Earth.
03:11 Photosynthesis plays a vital role in supplying our planet with oxygen,
03:15 since trees and plants convert carbon dioxide from the atmosphere
03:18 into the air we breathe.
03:20 So without algae, not only do we get less oxygen,
03:23 we also have a lot more carbon dioxide in our atmosphere.
03:26 This intensification of the greenhouse effect
03:29 would make some parts of the world unbearably hot.
03:32 You'd definitely notice this intense heat near the equator,
03:35 since our ocean currents wouldn't be circulating warm water and air the way they used to.
03:39 Convection currents help warm water from the equator get farther north,
03:43 while colder water from the north is able to cool hotter areas down south.
03:48 At the equator, warmer water can carry more salt,
03:51 so this denser water sinks lower,
03:53 while cooler water flows over top of it.
03:56 And in the far north, the water gets cold enough to freeze and form sea ice.
04:00 Salt gets left behind as the water freezes,
04:03 and naturally, this makes colder water up north denser,
04:06 allowing it to sink to the bottom,
04:08 to make room for the incoming warmer water that's worked its way up from the south.
04:12 But without salt, the whole process breaks down.
04:15 Earth's extremities would freeze, while weather around the equator would intensify.
04:20 For one thing, hurricanes would be a lot more frequent, and a lot more deadly.
04:25 At this point, our weather and our climate would be totally different from how we know it now.
04:29 How long would we survive to see all these changes?
04:32 Not long at all.
04:34 You'd either freeze, overheat, die in a natural disaster, or starve to death.
04:39 Yeah, with significantly less photosynthesis,
04:41 and climates that are either extremely cold or extremely hot,
04:45 our weather would no longer support the diverse plant life it has now.
04:48 The entire food chain would collapse.
04:51 Most species would die off, including humans,
04:53 since crops we rely on for sustenance would all disappear.
04:56 So when we say ocean salinization is important,
05:00 don't take it with a grain of salt.
05:01 Of course, we respect the scientific method,
05:04 so keep questioning the world and its properties, on land and beyond.
05:08 And come back soon for another WHAT IF.
05:11 [music]