Do We Need Rain?

[RhenMyster]

I'm writing a story and for it, I want to know if rain (or precipitation rather) is necessary for life. If rain is just the cycle (and forgive me for not knowing the true technical terms for this) is just evaporation of the ground water into clouds that cause precipitation back to the ground, then do we really rely on rain? I know crops dry up if it hasn't rained for a long period of time, but if say today was the last day for the rain due to pollution or something, would we be able to survive? Could we not irrigate? Or is it vital for it to rain?

 

On a further note, what could cause the end of precipitation?

[mezarashi]

Yes, we do need rain. For the world's vegetation relies on rain to redistribute water to where it would not usually occur. And of course, all other living things live off of plants. So if all plants die, so would they. If humans can live off a barren wasteland of a planet (I don't think we're ready yet technologically), then living on Mars wouldn't be a big deal would it. In addition, evaporation helps to maintain humidity in the air.

 

Most importantly I think it may have eluded you. Rivers flow because of rain!!! When it rains, the water collects together at a river and eventually drains out to the ocean where it re-evaporates and the cycle begins. Without rain, all the rivers in the world would dry up. And that would be bad

[Bettina]

I'm writing a story and for it' date=' I want to know if rain (or precipitation rather) is necessary for life. If rain is just the cycle (and forgive me for not knowing the true technical terms for this) is just evaporation of the ground water into clouds that cause precipitation back to the ground, then do we really rely on rain? I know crops dry up if it hasn't rained for a long period of time, but if say today was the last day for the rain due to pollution or something, would we be able to survive? Could we not irrigate? Or is it vital for it to rain?

 

On a further note, what could cause the end of precipitation?[/quote']

 

If the scenario is simply no more clouds or fresh water on land, we could still eat seafood, and heat/condense seawater to drink.

 

I can't imagine the end of precipitation.

 

Bettina

[ed84c]

And you are going to fit 6 bn people comfartabley around the beaches of the world, and there will be enough fish still to eat?

[Dak]

rain isnt the only form of precipitation. id immagine that fog, mist, snow and whatnot, or possibly just a slightly high air-humidity, could perform the function of rain for some life (although mass extinctions would result)

 

the bigger question is about clouds. they block out the suns rays at daytime, and insulate the world at night. so, if your no rain scenario equals no clouds, then that would possibly shaft the temperature in one way or another.

 

as for what could cease rain, either a significant increase or decrease in the temperature of the world. too cold, (ie to the point where the seas freeze over) and there will be no water going up, so no water coming back down (ie rain).

 

too hot, and although the water could go up, it would not condense and fall back down.

[Bettina]

And you are going to fit 6 bn people comfartabley around the beaches of the world, and there will be enough fish still to eat?

 

it's not what he was asking...

 

Bettina

[reverse]

oh good a story.

 

how are you going to get rid of the rain?

 

what is it about the planet earth that you will adjust?

 

where on earth is there already no rain?

 

is there ever rain in the desert?

 

is there rain at the poles?

 

what makes a cloudless day cloudless.....

 

there must be a cool hub to centre this story around...

 

thinking...thinking....

 

evaporation. water changing form...hmmm..... ice.... snow.... rain.... mist.... rivers .... ocean....evaporation.... clouds....hmmmm not an easy cycle to break....

 

introduced self replicating molecule synthesized from a comet causing water molecules to loose their ability to form into drops...

 

new form of air bourn water algae that colours the clouds green and purple...

suck up all the water then fall to earth with a great splash???

[reverse]

Ahh…set it back in the thirties…the Nazis have water collecting blimps which heard the clouds off to the pole to solidify them in order to control the world by controlling the fresh water.

And some idea where the increase in ice cap size has some sort of knock on effect and Tom Cruse and that girl from Dawson’s creek can be in the movie.

[RhenMyster]

Well, actually, I want to set the story in the future (Not flying car future and pill-sized meals). But I need the world in a terrible condition, where only the strongest countries are surviving because of greedy, dictators that only care for their country's success. So, in this thoery, it's okay if third world countries and other not-so-powerful countries die off.

[j_p]

Well, people survive in and around deserts now, so, theoretically, life would continue some how.

 

The US, Russia, China are all too big to survive; too many people and too much land mass with no water.

 

Make Norway the greedy powerful country; they have fjords and glaciers. They can perfect de-salinization [making use of the decreased humidity some how] and OUR HERO can steal their largest glacier, maybe using the last of the world's oil in the process. While OUR other HERO [make this one a female] works on genetically modifying food plants to grow in salted soil.

 

But who'll stop the rain?

Actually, we don't have to stop the rain, we can move it [well, actually, we probably can't]; would it work if rain only fell over the oceans, or at the poles? Or even around the equator? That would mean that, let's see, only South America, including northern Brazil, Indonesia and Africa would be getting rain. It doesn't look like a lot of land mass on my globe, but maybe enough to feed a sharply curtailed population if the entire area was intensively farmed. Brazil and Norway can form an alliance; the Congo can refuse to officially join, but work with them, and Indonesia, et al, can be torn apart by countries fighting to control their rain.

 

Of course, those pesky trade winds and ocean currents would keep trying to move the rain; I don't think we can stop the earth's rotation [the day/night thing is kind of important]...

What would happen to the weather if we got rid of tides? Can you blow up the moon?

 

Ok, stealing the glacier is silly.

[Spyman]

How about if a large body enters the solar system from the darkness of space, with unknown origin inside the Milky Way, and while not hitting Earth it passes by close enough to change Earth's orbit by it's gravitational influense, and then continues out to unknown space again.

 

The Earth ends up in a more loopy elliptical orbit which roasts it a smaller part of the year and then freezes it for a longer part.

 

It won't stop the rain but will surely mess up the world to a "terrible condition", by change of the weather.

 

Fully possible, (but unlikely), in a future time span for say 25 to 100 years from now.

[YT2095]

actualy, more to the point, rather than "Do we need rain" the issue would be How would you avoid it?

 

it`s an inevitable consequence of liquid water

[coquina]

I'm writing a story and for it' date=' I want to know if rain (or precipitation rather) is necessary for life. If rain is just the cycle (and forgive me for not knowing the true technical terms for this) is just evaporation of the ground water into clouds that cause precipitation back to the ground, then do we really rely on rain? I know crops dry up if it hasn't rained for a long period of time, but if say today was the last day for the rain due to pollution or something, would we be able to survive? Could we not irrigate? Or is it vital for it to rain?

 

On a further note, what could cause the end of precipitation?[/quote']

 

Well the first thing you need to do is some research so that you understand the water cycle. Here is a link from USGS.

http://ga.water.usgs.gov/edu/watercycle.html

 

Read this so that you understand the whole process. Then, I suggest that you base your book on what would happen if one part of the water cycle was disrupted.

 

Have you ever heard of "Chaos Theory"? It's the idea that changing one small thing causes changes all down the line that have far reaching and often unpredicatable consequences.

 

Step number one - do the research - learn the water cycle. Your book will be totally unbelievable if it doesn't have a basis in fact.

[RhenMyster]

Yes, I know. Which is why I immediately posted this topic on a lot of these Science Forums, just to see if my story has a possibility. The idea of a world corrupted and torn to shreads because of money is what keeps the men in control dying out without rain. But first, I wanted to know how could rain stop and what would happen if it did. But thanks for all the information. Any other suggestions are well appreciated.

[RhenMyster]

Let me pose another question. Perhaps the evaporation is taking place, but the precipitation is never falling to the ground. Maybe the clouds just are cooling off enough for the rain to form and fall.

[Skye]

That happens sometimes in reality. If you pay attention you can see it happening sometimes, not above you so much as in the distance. Typically happens when there a big difference in temp/pressure with altitude, eg rain falls from cool/dense air into warm/less dense air and evaporates. Doesn't happen alot because warm/low pressure air rises.

[Dak]

if water goes up, it would eventually have to come down lest the entire ocean end up mysteriously suspended above our heads.

 

id guess it could either come down in a place where it is useless to agriculture (centre of the sea as someone sujjested), or possibly something to do with the ozone layer/earths magnetic field being removed and our atmosphere slowly buggering off into space, although i have no idea how plausable the last idea was and it wouldnt be a sustainable situation for very long in planetery terms (although could help the scenario: humans have to simultaniously survive against the lack of rain and also race against time to build a space-ship to reach alpher-centuri or something, although i suspect everything after the red word above is, scientifically speaking, bolox.

 

couldnt humans just build contained biospheres anyway?

[RhenMyster]

Ok, I think I'm making this more difficult than it should be. What I need for my story is a way the rain would stop for at least 20-25 years. Could that be possible? People can die, land can be killed, the world could go crazy, etc.

[Guest Tecnogram888]

Ok, I think I'm making this more difficult than it should be. What I need for my story is a way the rain would stop for at least 20-25 years. Could that be possible? People can die, land can be killed, the world could go crazy, etc.

blow up the sun, lol. or block it out with some huge object that keeps all of earth in a total solar eclisre. not gonna happen though. the world would just simply freeze as an ice age takes over due to lack if solar heat and energy reaching earth and all will die. plants=bottom of trophic level=required for life to exist. but it needs sunlight, and blcoking sunlight would be the only way ur gonna stop rain. so everything but chemoautotrophicc organisms near hydrothermal vents will die.

[j_p]

Ok, I think I'm making this more difficult than it should be. What I need for my story is a way the rain would stop for at least 20-25 years. Could that be possible? People can die, land can be killed, the world could go crazy, etc.

So, you won't blow up the moon?

 

Do you have to have a reason? In The Children of Men, the author just had humans stop reproducing; possible reasons were suggested, but never clearly explicated.

 

Whatever the reason is, use the narrative device of having a non-scientist explain it to a child; then the readers can mentally attribute any factual inaccuracies and over-simplications to the characters, and not to the science.

 

From Coquina's link:

"As air is cooled, the evaporation rate decreases more rapidly than does the condensation rate with the result that there comes a temperature (the dew point temperature) where the evaporation is less than the condensation and a droplet can grow into a cloud drop."

 

You want to create a stable environment where evaporation and condensation are in equilibrium. That should be easy enough.

 

Warm the surface of the earth; increased evaporation will increase the overall cloud mass; as the cloud mass increases and traps radiant energy against the earth, the temperature will increase further, more water will evaporate, increasing the cloud mass, and, subsequently, the earth's surface temperature. Eventually, an equilibrium is reached in which there is a permanent cloud cover over the earth. Water will have to be mined from the clouds.

 

Maybe you could restrict the cloud cover to the temperate zones; then in the tropics, evaporation would occur, warm wet air would rise, hit the significantly cooler upper atmosphere [radiant energy trap by the cloud cover would be unavailable to the upper atmosphere]; I think you'd get primarily nasty hail-storms, so precipitation would be a curse.

 

The warmer air from the tropic would flow over the temperate zone cloud cover, and push down on the poles. That, combines with the sun's energy, would heat the caps, causing them to sublimate; that would dramatically increase the amount of water available for the cloud cover. Push the cooled air back under the cloud cover. You get some hellacious weather.

 

Particulates in the atmosphere encourage the formation of rain droplets, so remove as many sources of particulate air pollution that you can; create a world-wide ban on burning wood and fossil fuels. Combine this with a period of no volcanic activity. [aside]Then, if you want, you can use a massive volcanic eruption [increased particulates, more and larger rain drops, decreased cloud mass and surface temperature] as a deus ex machina.[/aside]

 

The seasons will interfer with all this, so get rid of them. You will need to straighten out the earth on its axis, and change its orbit from elliptical to circular. A massive explosion in space on the side of the earth away from the sun at the Winter Solstice should do the trick.

 

So, blow up the moon.

[RhenMyster]

Wow...that was incredible. A completely interesting look on it, if what all you said is true. (And considering this forum, if you're not, you'll be called on it in no time.) So blow up the moon? Any idea how that could, in someone's naive mind, be beneficial?

[Guest Tecnogram888]

So' date=' you won't blow up the moon?

 

Do you have to have a reason? In [i']The Children of Men[/i], the author just had humans stop reproducing; possible reasons were suggested, but never clearly explicated.

 

Whatever the reason is, use the narrative device of having a non-scientist explain it to a child; then the readers can mentally attribute any factual inaccuracies and over-simplications to the characters, and not to the science.

 

From Coquina's link:

"As air is cooled, the evaporation rate decreases more rapidly than does the condensation rate with the result that there comes a temperature (the dew point temperature) where the evaporation is less than the condensation and a droplet can grow into a cloud drop."

 

You want to create a stable environment where evaporation and condensation are in equilibrium. That should be easy enough.

 

Warm the surface of the earth; increased evaporation will increase the overall cloud mass; as the cloud mass increases and traps radiant energy against the earth, the temperature will increase further, more water will evaporate, increasing the cloud mass, and, subsequently, the earth's surface temperature. Eventually, an equilibrium is reached in which there is a permanent cloud cover over the earth. Water will have to be mined from the clouds.

 

Maybe you could restrict the cloud cover to the temperate zones; then in the tropics, evaporation would occur, warm wet air would rise, hit the significantly cooler upper atmosphere [radiant energy trap by the cloud cover would be unavailable to the upper atmosphere]; I think you'd get primarily nasty hail-storms, so precipitation would be a curse.

 

The warmer air from the tropic would flow over the temperate zone cloud cover, and push down on the poles. That, combines with the sun's energy, would heat the caps, causing them to sublimate; that would dramatically increase the amount of water available for the cloud cover. Push the cooled air back under the cloud cover. You get some hellacious weather.

 

Particulates in the atmosphere encourage the formation of rain droplets, so remove as many sources of particulate air pollution that you can; create a world-wide ban on burning wood and fossil fuels. Combine this with a period of no volcanic activity. [aside]Then, if you want, you can use a massive volcanic eruption [increased particulates, more and larger rain drops, decreased cloud mass and surface temperature] as a deus ex machina.[/aside]

 

The seasons will interfer with all this, so get rid of them. You will need to straighten out the earth on its axis, and change its orbit from elliptical to circular. A massive explosion in space on the side of the earth away from the sun at the Winter Solstice should do the trick.

 

So, blow up the moon.

 

wth, r u not aware of the consequences of global warming? water vapor in air=rising average temperature=more greenhouse gasses in atmosphere, not only water. if all the water is evaporated into the air, temperatures get hot enough to start baking Carbon Dioxide out of rocks. since carbon dioxide is the major factor of global warming, increased concentrations of it skyrockets the temperature to a point where earth's gravity cannot hold in the speeding evaporated water molecules, and they escape out into space. gradually, other stuff i'm too lazy to type up happens and earth becomes an imitation of venus with clouds of carbon dioxide and sulfur, with no traces of water. equilibrium=non-existant

 

restrict cloud movements? wtf, r u going to buld a wall 1km up into the sky to keep clouds from passing the temperate zones.

 

water vapor in the air that looses tons of energy as it moves to the north, itsgoing to hold enough heat to cause ice to subliminate?! WTH, in ur dreams. ice at 0 degrees celcius to vapor at 100 degrees celcius=720 calories of specific heat. this means the water vapor's gona have to be at a temperature of atleast 820 degrees celcius. at that temperature, water molecules would be moving fast enough to escape earth's atmosphere far before it reaches the poles.

 

if u know phys, u'd know its impossible for perfectly circular orbits because of the fact that a planet's mass exerts a gravitational force on the sun, causing it to wobble and move around. Thus, as u measure a planet's orbit relavitve to the sun, it is going to be elliptical with the sun at a foci, or the planet would be spiralling closer or further from the sun. Circular orbits can only exist if the sun is stationary and unaffected by the gravitational pulls of plantes, which it isnt.

[RhenMyster]

Okay...so no rain is basically out of the question without destroying the world. But! I'm flexible, so don't worry. How about a system where rain fall is scarce in many parts of the world, particularly the US? Perhaps it rains about once to twice a year? Would the world survive that? And if so, what would cause that?

[j_p]

Hey, Tecno, work with me here.

We are not creating a functional environment, we are working up an explanation that will take maybe one paragraph and be read primarily by people who don't even remember that the earth's orbit around the sun is elliptical, never mind understand why. This is fiction; the idea comes first, then the underlying details.

 

So, for the sake of fiction, we are going to assume equilibrium is reached, and then tackle the details of how.

 

I came up with a starting point. Thank you for the other issues to address.

 

Greenhouse gasses, especially CO2; how to achieve the restricted cloud cover; sublimation at the poles; impossibility of circular orbit.

 

You have no problem with me blowing up the moon to knock the earth straight on its axis?

 

And don't be snippy.

 

Ok, here goes:

The greenhouse gasses, including CO2.

 

Well, we are going to achieve the new water cycle equilibrium BEFORE the temperature gets hot enough to bake the CO2 out of the rocks.

 

We have already stopped burning fossil fuels and wood; toss in a few more low light, low water plants to suck up the CO2; mosses are out, they need too much water; check out a gardening site, they have databases that suggest plant for any conditions; there is a consequence you might not have thought of, greatly reduced number of plant species.

 

I would really like to grow a layer of moss on the underside of the cloud cover; that would be fun. Any ideas how to do that?

 

Restricting cloud cover to the temperature zone

Well, the weather will be different at the equator and poles from temperate zones. So, the cloud cover will be only at the temperate zones. Now we have to come up with a reason why.

 

I have theorized it is because the greater sun's energy at the equator means that the air gets hotter, rises faster, and rolls over the cloud cover. I think that hellacious storms are going to be necessary.

 

Sublimation at the poles

No problem; water sublimates at the poles. I think. What the hell, we can leave that detail out; even if I am right, too many people will dis-believe it for it too work in the story. The last thing we want is to push at the willing suspension of disbelief.

 

Impossibility of circular orbit

Well, if we can't have a circular orbit, we can't. How close to circular can we get? And while we're at it, what would messing with the orbit to do the period of rotation? Would we end up with a longer or shorter daylength?

 

Additional points

Remember, the earth is a very complicated system; current theories about the consequences of global warming could be wrong; so we CAN create our own scenario of exactly what happens. I think tossing in an abrupt end to the burning for energy is a good idea.

 

If we need to keep up current energy use, I think we should use wind power; that will tie in with the hellacious storms.

 

And our scientists will not know exactly why the earth's environment changed so rapidly to our current configuration; they will theorize and argued and contradict one another, so we don't need to have all the details right.

 

We are NOT evaporating all the water, just enough to create a semi-permanent cloud cover over about half the earth's surface.

Does anyone know how much water that would take? We might have to sublimate, or MELT, the poles after all.

 

I have rethought my plot device about having a non-scientist explain things to a child, way too obvious. Do NOT use it. Here's another idea; have the religious fundamentalist believe that the change in the environment is God preparing the earth for the Great Conflagration by which he will destroy the earth; introduce any scientific 'facts' you want in arguments with the RFs.

Sorry, I'm not the writer; just an idea.

[j_p]

Wow...that was incredible. A completely interesting look on it, if what all you said is true.

 

Um, I really did mix up reality and your fictional environment, didn't I? I was just to lazy to watch my verb tenses and toss in lots of qualifying clauses. That post was the result of abusing perfectly legal substances, i.e., caffeine and nicotine.

 

Don't let Tecno scare you; if you want to stop all rainfall over the US, you can. Just face down a few technical quibbles. Remember, you don't have to be right, you just have to be consistent. [but I think stopping the rain on a single continental mass would be harder than my suggestion.]

 

This thread is not getting enough attention; you need more feed back on details. For example, I did not know planetary obits could not be circular.

 

And I strongly suspect that blowing up the moon will not work, as fond as I am of the idea.

 

Do you mind if I do some research on what happens when the Moon blows up?