What If We Drained the Pacific Ocean? | Unveiled

VOICE OVER: Noah Baum WRITTEN BY: Caitlin Johnson
The Pacific Ocean is by far the biggest ocean we have! It holds more than half of Earth's total water and covers 63 million square miles. But what would happen if it disappeared? In this video, Unveiled discovers how drastically the world would change were we to drain all of the water out of the Pacific Ocean...

What If We Drained the Pacific Ocean?

Water is the most important resource on our planet, and the oceans contain 97% of all the water we have. The Pacific Ocean is by far the largest of all, boasting more than half of Earth’s total water and covering 63 million square miles. But could this ever change?

This is Unveiled, and today we’re answering the extraordinary question; what if we drained the Pacific Ocean?

If we were to drain water from Earth with any kind of efficiency, it’d make most sense to do it from the Pacific. More specifically, we’d need to insert some sort of colossal plughole into Challenger Deep, at the bottom of the Marianas Trench and the deepest place in the seabed that we know of. Challenger Deep is almost 36,000 feet down, and it’s where we’d most likely build the drain for maximum effect.

Science author Randall Munroe has done an especially in-depth analysis of just what would change in this scenario. Say that this gaping hole, or plug, or portal, or whatever you want to call it was around 10 metres wide... actually draining the water could still take hundreds of thousands of years! The reality is that because most seas and oceans are connected, this hypothetical would really affect the entire planet… and not just the Pacific region. Unless whoever installed this unprecedented draining plug also built gigantic walls to separate one sea from the next - which, for today’s video, let’s say that they haven’t - “draining the Pacific” ultimately means also draining all of water connected to it; including the water from most of Earth’s other oceans.

The most significant effect of draining the ocean would be the creation of new landmasses. Previously submerged sections of the seabed would rise above the surface as the water level sinks. According to Munroe, after 2,000 years sea levels will have dropped by 50 metres; a point at which certain islands would cease to be islands as they’d now be connected to the mainland. Sri Lanka joins India; the UK eventually connects to mainland Europe; and previous clusters of islands reshape into bigger masses, with parts of Indonesia forming new geographical bonds to become one.

At this point, principles for how to determine new national borders would have to be decided. Legislation might simply say that the new border has to be halfway between what the old coastlines were, though determining the “old” coastlines might also be tricky because this monumental change would happen so gradually. As well as pre-existing places changing shape, though, brand-new islands with no nation currently to their name would also emerge - including the freshly exposed Grand Banks, which would eventually arise once more than 100 metres of water was siphoned from the Canadian east coast. Over the course of multiple millennia, and all across the world map, we’d see one-time islands conjoin with other large slabs of land, one-time underwater landscapes brought to the surface, and the coastlines of every major continent lengthened… all from just one hypothetical hole at the bottom of one ocean.

Not all the new landmasses would be made of plain sand and rocks. The Pacific Basin is encircled by what’s known as the “Ring of Fire”, an undulating belt which harbours some intense geological activity. At the edges of the Pacific tectonic plate there are thought to be at least 452 volcanoes and fault lines bordering everywhere from the Americas to East Asia and Australasia. Many of these volcanoes are currently underwater, which makes them a little less dangerous to us; while earthquakes and tremors from their eruptions can be destructive, we don’t get the lava or ash clouds as with eruptions on land. But, were the sea to be drained and the sea levels to dramatically drop, these deadly mountains would be exposed, and the new land uncovered around them could be extremely dangerous. That said, the new volcanoes coupled with the eventual appearance of places like the world’s longest mountain range – the Mid-Atlantic Ridge – would offer an exciting opportunity for mountaineers and hikers, providing all new summits to scale.

While we do already know about features like the Ring of Fire and the Mid-Atlantic Ridge, however, the vast majority of the ocean is currently unknown to us - with the US National Oceanic and Atmospheric Administration citing that around 95 percent of it is still unexplored. So, is it possible that in draining the water we’d discover things we never knew existed?

Not only would ocean drainage mean we could visit and examine shipwrecks that we’ve already mapped, for example, but it would also make it easier to find other lost ships for the first time. Perhaps we’d unearth answers to real-world mysteries like the disappearance of Amelia Earhart somewhere over the Pacific, while the myths and legends of the oceans could all be checked and verified, too - from the fabled lost city of Atlantis, to the supposedly supernatural Bermuda Triangle. By bringing the deepest parts of the ocean closer to us, we’d also be sure to find evidence of marine life we never even knew about… and perhaps even of ancient creatures like the Megalodon, which some argue could still exist. But, herein lies the greatest and most obvious problem with this particular hypothetical - and the reason why it’s a relief that it could never happen… because say we did discover millennia old Megalodon, by the time we’d drained enough water off to find them, they’d probably be dead.

Right now, with rising sea levels being a chief environmental concern, the prospect of purposefully forcing sea levels to drop almost sounds like a good thing; resulting in a lower risk of flooding, and more land than ever to live on. But, in doing so we’d have also inflicted dire consequences onto all marine life. As the volume of ocean decreased, wide-ranging habitats would be destroyed, with Earth’s underwater ecosystems disappearing one by one. It would be a very gradual process, but for everything living in the ocean it’d feel like being trapped in a room while the ceiling is slowly lowered.

Long before the water had been totally drained the millions of aquatic populations would’ve decreased to extinction. Which is not only bad news for them, but also bad news for us. Marine algae is one of the world’s most abundant organisms… and it’s also responsible for producing as much as 80% of Earth’s oxygen through photosynthesis. Sure, we’d still have some large but isolated waters regardless of the Pacific drain, but thanks to the ecological damage it’d cause, we’d be severely slashing the amount of oxygen naturally produced for us to breathe. In the long term, it’d be a situation to shake even the most fundamental aspects of life on Earth by ultimately rewriting the makeup of our atmosphere.

There are even deeper effects to be had on the climate, too. Because the oceans as they are absorb lots of solar radiation and disperse heat around the planet, if the water level dramatically reduced the planet would get significantly hotter. So hot, in fact, that forest fires would be an everyday risk across much of the dried-out map, destroying a lot of the life left to fend for itself on the surface, and adding increased amounts of carbon into air that’s already being choked of oxygen. Because of the temperature increase the ice caps would melt as well, until they were eventually drained away themselves. And, with such little remaining water, not even the water cycle would work as it should do - with less moisture in the air leading to fewer clouds, less rain and more drought.

Despite all this, however, there is a slim possibility that humans could survive this scenario. And that’s because not all of the water would be gone. Even were the plug to be positioned at the bottom of the deepest part of the Marianas Trench, we’d still be left with various land-locked seas, lakes and trenches… so a dwindling human population would still have access to water, if they could travel to any remnant of ocean spared. With the rest of the planet turned into a sprawling desert, most would head to the poles where the temperatures wouldn’t be quite as extreme.

But, again, all of this would play out over an exceptionally vast period of time. So, with thousands of years between the oceans as they are now and total, barren dryness, there’s also the possibility that humans could have in some way evolved and adapted to Earth’s new circumstances by the time they get too out of hand. Failing that, a new, dominant, probably reptilic species may have established itself in the ocean-less world. Or humanity might’ve redistributed all of the water it had drained to somewhere else… Perhaps even to a different planet entirely, like Mars, in an effort to fast-track plans to terraform a Second Earth in space.

Of course, the most sensible option is simply never to build an ocean drain in the first place. Yes, some water would remain, but Earth as we know it would be gone; replaced by a hostile, desert world with far fewer plants and creatures struggling to survive on its almost endless landmasses. And that’s what would happen if we drained the Pacific Ocean.