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#What would happen if it rained on Earth for an entire year without stopping?
Not a storm. Not a monsoon season. Three hundred and sixty five days of continuous rainfall over every continent at once, with no break, no sun, and no dry ground anywhere on the planet.
For the first day it would look almost beautiful. By the end of the first week, every drainage system built by humans would have already failed. By the end of the first month, the soil itself would have stopped absorbing water, which is the moment everything changes, because rain that cannot sink has nowhere to go but sideways.
In this documentary we follow all twelve months in order. The flash floods. The rivers abandoning their channels. The landslides that follow saturated hillsides. The dams holding back more water than they were ever designed for. The harvests that fail on every continent in the same season. The slow collapse of a food system that assumed the sun would come back.
And then the part most people never think about: the rain is not the biggest problem. The missing sunlight is. Twelve months of permanent cloud would shut down photosynthesis across most of the planet, cool the surface, and starve the food chain from the bottom up, exactly the way a volcanic winter does.
We also answer the question everyone asks first. Would Earth be completely submerged? No, and the reason is one of the strangest facts in atmospheric science: if you condensed every drop of water currently in the air into rain, it would only cover the planet to about two and a half centimetres. For it to rain for a year, the oceans would have to lift themselves into the sky and fall back down, over and over, hundreds of times.
Then, on day three hundred and sixty six, it stops. What the sun comes back to is not the world it left.
CHAPTERS
00:00​ - Introduction: What If Rain Never Stopped?
01:43​ - Setting the Rules: How Much Rain?
03:31​ - The Atmospheric Physics Problem
05:16​ - Days 1 to 3: The Deceptive Calm & Soil Saturation
06:41​ - Month 1: Global Landslides & Structural Collapse
09:00​ - The Agricultural Catastrophe: Root Suffocation
10:48​ - Month 6: Ocean Desalination & Massive Erosion
12:44​ - Who Survives? (Fungi, Insects, and Humans)
14:17​ - The Carnian Pluvial Episode: Earth’s Real Million-Year Rain
16:16​ - Day 365: The Rain Stops & The Aftermath
17:42​ - Conclusion: The Fragility of Natural Cycles
This is a science based thought experiment built on real atmospheric physics: global precipitable water, evaporation rates, soil infiltration limits, river discharge capacity and the measured effects of reduced sunlight on crop yields.
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Transcript
00:14Somewhere on Earth, right now, it is raining.
00:18That is not a guess.
00:20At any given moment, roughly 5% of the planet's surface has rain falling on it.
00:26Somewhere over the Amazon, over the Pacific, over a street in a city you will never visit, water is falling
00:33out of the sky.
00:35And it has been doing this for about 4 billion years.
00:39Rain is so ordinary that we have built our entire relationship with the sky around it being temporary.
00:46We wait it out. We carry umbrellas.
00:49We say the word forecast and we mean that it will stop.
00:53So here is the question.
00:56What if it did not stop?
00:58Not a flood, not a storm, just rain falling everywhere on Earth, on every continent and every ocean, at the
01:07same time, for 365 days, without a single break.
01:12How deep does the water get?
01:15What happens to the sky?
01:17What happens to the crops, the cities, the ground beneath them?
01:22And here is the part that makes this worth your time.
01:25This is not entirely hypothetical, because the Earth has done something like this before.
01:32The rain lasted considerably longer than a year, and when it finally stopped, the dinosaurs ruled the planet.
01:40Let's find out what happens.
01:43Before anything else, we need a number, because it rains for a year is meaningless without knowing how hard.
01:51So let's set the rules carefully.
01:54Global average rainfall is roughly 1 meter per year, but it is wildly uneven.
02:01Deserts get a few centimeters.
02:03Some tropical regions get 10 meters or more.
02:06Parts of northeast India hold records above 11 meters in a single year.
02:12For our scenario, we are going to assume steady, moderate rain everywhere on Earth continuously.
02:19Not a monsoon downpour, not a drizzle.
02:23Something like a persistent, soaking rain of roughly 5 millimeters per hour.
02:28That is not dramatic.
02:30You would walk through it without panicking.
02:33But run the arithmetic, and it stops being gentle very quickly.
02:385 millimeters an hour is 120 millimeters a day.
02:42That is 12 centimeters of water falling on every square meter of the planet every 24 hours.
02:50Over a year, that comes to roughly 44 meters of rainfall.
02:5644 meters on every part of the Earth's surface simultaneously.
03:03To put that in perspective, the wettest place on Earth receives around 11 meters in an exceptional year.
03:09And we are proposing four times that, delivered to the Sahara, to Antarctica, to Mumbai, and to the open Pacific
03:18at the same time.
03:20So we are not talking about a wet year.
03:23We are talking about the atmosphere behaving in a way it has never behaved in human history.
03:30And immediately, we have a physics problem.
03:34Here is what almost every version of this scenario ignores.
03:38Rain is not created by the sky.
03:41It is recycled from the ground.
03:44Every drop of rain that has ever fallen on this planet was, shortly before, water sitting on a surface somewhere.
03:51The sun heats the oceans and the land, water evaporates, rises, cools, condenses into cloud, and falls again.
04:01It is a closed loop, and the engine driving it is sunlight.
04:06So if we want continuous global rain for a year, something has to lift 44 meters of water into the
04:14atmosphere.
04:15Where does it come from?
04:17The oceans, obviously.
04:19They hold the overwhelming majority of the planet's water.
04:23But to evaporate that much water, you would need an enormous amount of energy, far more than the sun currently
04:30delivers.
04:31And here is the contradiction at the heart of the scenario.
04:35Our permanent rain requires permanent cloud cover.
04:39And permanent cloud cover blocks sunlight, which is the very thing powering the evaporation.
04:45The system would strangle itself.
04:48So for this thought experiment, we are going to do what physicists do, and cheat deliberately.
04:55We will assume the water is supplied, that the hydrological cycle is somehow being fed from outside.
05:02And we will focus on what happens on the surface.
05:06But keep that contradiction in mind, because it comes back at the end, and it is the reason the real
05:12version of this event looked very different.
05:16The first few days are, strangely, not frightening.
05:21Rain falls everywhere.
05:23Deserts that have not seen a proper storm in years turn dark with water.
05:29The Sahara is wet.
05:31Antarctica receives rain instead of snow.
05:35Every new service on Earth leads with the same story.
05:39And the unprecedented rainfall event continues to spread across the region.
05:44The initial effect is almost beautiful.
05:48Dry riverbeds fill.
05:50Dust settles out of the air.
05:53Air quality in polluted cities improves dramatically, because rain scrubs particulates out of the atmosphere.
06:01But by day three, the ground stops cooperating.
06:05Soil can only absorb water at a certain rate, and that rate varies enormously.
06:12Sandy soil drinks quickly, clay does not.
06:16And crucially, once soil is saturated, it stops absorbing altogether.
06:22Everything after that becomes runoff.
06:25In most of the world, saturation happens within the first few days.
06:29From that point on, every drop that falls has to go somewhere.
06:34And the only direction available is sideways and downhill.
06:41By the end of week one, roughly 80 centimeters of rain has fallen worldwide.
06:47Rivers everywhere are rising at once, which is the key difference between this and a normal flood.
06:54Normally, a flooded river can discharge into a calm sea, or a dry region can absorb water from a wet
07:01one.
07:02Now there is nowhere to send it.
07:05Every catchment on earth is filling simultaneously.
07:09By the end of the first month, around three and a half meters of rain has fallen.
07:15Rivers have burst their banks on every continent.
07:19Low-lying regions are underwater.
07:21But the more interesting danger is not the water you can see.
07:26It is what water does to soil.
07:29When soil becomes saturated, the water fills the spaces between the grains.
07:35And that water pushes outward.
07:38It reduces the friction holding the particles together.
07:42Engineers call this poor water pressure.
07:45And it is the reason heavy rain causes landslides.
07:49A hillside that has stood stable for 10,000 years can fail after a few days of saturation,
07:56because the soil is no longer gripping itself.
08:00After a month of continuous global rain, every slope on earth is at or beyond saturation at once.
08:09Landslides begin everywhere there is a gradient.
08:13Mountain roads are cut.
08:14Hillside settlements fail.
08:16Entire slopes slump into valleys.
08:20And the same mechanism attacks everything we have built.
08:25Foundations rely on stable ground.
08:28Saturated ground is not stable.
08:31Buildings begin to settle unevenly.
08:34Retaining walls fail.
08:37Dams, which are engineered to hold a specific maximum load,
08:41face sustained inflow far beyond their design assumptions.
08:45And spillways run continuously.
08:49Some dams overtop.
08:51Some fail entirely.
08:53And there is something else happening by now,
08:56far less dramatic and far more serious.
09:00Agriculture has stopped.
09:03This is the part of the scenario that decides everything.
09:07And it has nothing to do with drowning.
09:10Most people assume plants love rain.
09:13They do, up to a point.
09:16But roots do not only need water, they need oxygen.
09:21Plant roots respire, taking in oxygen from the tiny air pockets within the soil.
09:27And when those pockets are permanently filled with water, the roots suffocate.
09:32The condition is called water logging, and it kills most crops within days to a few weeks.
09:40Rice, which grows in flooded paddies, is a rare exception.
09:45And even rice has limits, because it needs its leaves above the water.
09:50So within the first month, wheat, maize, soy, potatoes, and nearly every staple crop on the planet is dying in
10:00the field.
10:01At the same time, in every growing region.
10:04There is no harvest coming.
10:08Not in this hemisphere.
10:09Not in the other one.
10:11Not anywhere.
10:13And on top of that, there is the light.
10:17Permanent global cloud cover means a dramatic reduction in sunlight reaching the surface.
10:23Photosynthesis slows across the entire planet.
10:27In crops, in forests, and critically, in the phytoplankton at the surface of the ocean,
10:33that produce a large share of the world's oxygen and sit at the base of the marine food chain.
10:40The world does not starve because the water rose over its head.
10:44It starves because nothing grew.
10:48Halfway through, roughly 22 meters of rain has fallen.
10:53Now, a reasonable question.
10:55Does the earth actually flood?
10:58Does the sea level rise 22 meters?
11:02The answer is no.
11:04And the reason is important.
11:07Almost all of that water is being recycled.
11:10It evaporates from the ocean, falls on land, and runs back to the ocean.
11:15The net addition to global sea level is far smaller than the total rainfall,
11:21because the same water is being used over and over.
11:24But that does not mean the sea stays where it is.
11:28Enormous volumes of fresh water are now pouring off the continents into the oceans continuously.
11:35Coastal seas become dramatically less salty, which matters more than it sounds,
11:41because marine organisms are finely tuned to specific salinity ranges.
11:46Coral reefs, shellfish beds, and coastal fisheries suffer badly.
11:51There is also a deeper effect.
11:54Ocean currents are driven partly by differences in salinity and temperature.
11:59Flood the surface of the North Atlantic with fresh water,
12:02and you interfere with the circulation that moves heat around the planet.
12:06On land, the damage is more visible.
12:10Six months of continuous runoff strips topsoil on a scale that is difficult to imagine.
12:17Topsoil takes centuries to form, and can be removed in a season.
12:22Rivers run thick with sediment.
12:25Deltas grow outward.
12:27Lakes fill with silt.
12:29The actual shape of the land is being rewritten.
12:33And inland, in low-lying basins without drainage, standing water does not leave.
12:40Entire regions become permanent, shallow lakes.
12:43So who comes through this?
12:46It helps to invert the question.
12:48Instead of asking, what is strong?
12:51Ask, what does not mind being wet?
12:54Fungi thrive.
12:56Warm, permanently damp conditions are close to ideal for them,
13:00and fungal growth would explode across every surface,
13:04including inside buildings, on crops, and on bodies.
13:09Insects that breed in standing water, mosquitoes above all,
13:13would multiply enormously, and with them, the diseases they carry.
13:19Amphibians do well.
13:21Frogs and salamanders are built for exactly this.
13:25Aquatic life in rivers and lakes expands into territory that used to be dry land.
13:32And humans?
13:33We do not drown, mostly.
13:36We are good at moving uphill, and we are good at building shelter.
13:40What we cannot do is eat.
13:43The limiting factor for human survival in this scenario is not water.
13:48It is calories.
13:50Global food production collapses within the first two months,
13:54and stored reserves worldwide are measured in months, not years.
13:59A year of rain is comfortably long enough to exhaust them.
14:03The survivors would be in highlands with stored food,
14:07with the ability to grow something undercover and far from the landslides,
14:12which is a very specific and very small description.
14:17Now here is the part that should change how you think about all of this.
14:21Around 230 million years ago, in the late Triassic, the Earth experienced something geologists call
14:29the Carnian Pruvial episode.
14:31In rock rows from that period, all over the world, scientists find a distinctive signature.
14:38Sediments that indicate a sudden shift from dry conditions to persistently wet ones,
14:45laid down across widely separated continents at the same time.
14:49The leading explanation involves an enormous episode of volcanic activity,
14:55which pumped vast quantities of carbon dioxide into the atmosphere,
15:00warming the planet, increasing evaporation, and intensifying the global water cycle.
15:06How long it lasted is debated, with estimates generally running into the hundreds of thousands
15:12to roughly a million years or more.
15:15And it was not literally continuous rain everywhere, which is why our thought experiment had that
15:21physics contradiction. It was a long period of dramatically wetter conditions,
15:27with heavy rainfall across regions that had been arid. But the consequences are the part that matters.
15:34That episode is associated with significant turnover in life on Earth. Some groups declined sharply,
15:42and in the aftermath, one group that had been a minor presence expanded dramatically,
15:48the dinosaurs. The wet period is widely linked to the moment dinosaurs stopped being bit players
15:55in the Triassic and began their rise toward dominating the planet for the next 135 million years.
16:04So the honest answer to our question is that a sustained global wet period does not end life on Earth.
16:12It replaces who runs it. On day 365, the rain stops, the clouds break, and sunlight reaches the surface of
16:23the Earth
16:24Earth for the first time in a year. It would be the most emotional moment in human history,
16:30and it would also be the beginning of a second set of problems.
16:35The ground is saturated to depth, and it will take months to drain.
16:41Standing water across entire regions becomes a breeding environment for disease on a scale
16:47modern medicine has never faced. Topsoil across much of the world is gone, washed into the sea,
16:56which means that even with sunlight restored, the first planting season would be poor.
17:03Infrastructure is wrecked, not dramatically, but comprehensively. Roads undermined, foundations
17:10shifted, rail lines buckled, every underground system flooded. And ecologically,
17:17the planet is now running a very different experiment. Species that thrived in the wet year are
17:23abundant. Species that depended on dry habitat are not. Those imbalances take decades to resolve,
17:31and some never do. Recovery would be measured in years for the water, in decades for the ecosystems,
17:39and in centuries for the soil. Here is what I find striking about this scenario.
17:46We think of rain as a mild thing, the weather that cancels a picnic, the reason for an umbrella stand
17:52by the door. Of all the ways the sky could kill you, water falling gently out of it seems like
17:59the
17:59least threatening. But run it long enough, and it dismantles everything. Not by force. Rain does not knock
18:07buildings down. It saturates the ground until the ground stops holding them. It does not kill crops by
18:15violence. It fills the spaces in the soil until the roots cannot breathe. It does not destroy
18:21civilization in an afternoon. It simply refuses to stop. And everything we have built assumes that
18:29eventually it will. That is the real lesson here. Almost nothing we rely on is designed for permanence.
18:37It is designed for cycles. Wet season and dry season. Flood and recede. Grow and harvest. Take away the
18:47water. The rain is stopping, and the system fails. Not because the force is overwhelming, but because the
18:53pause never comes. And somewhere in the rock beneath your feet, there is a layer that records the last
19:00time this happened. Laid down over hundreds of thousands of years of a wetter world. In a period that ended
19:08with a group of small, unremarkable reptiles walking out into an empty landscape and inheriting the earth.
19:16The rain stopped eventually. It just took rather longer than a year.
19:21The rain stopped. The rain stopped. It doesn't seem to be aiana. The rain stopped. It was a fire.
19:23The rain stopped. The rain stopped. The rain stopped. The rain stopped. It turned on in the sea.

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