What If All the Sea Water Becomes Fresh Water?

WHAT IF

What if we didn’t have to worry about water consumption?

Transcript

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]

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