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Lower Thermal Radiation Input Needed To Trigger Planetary 'Runaway Greenhouse'

Unknown Lamer posted about a year ago | from the poor-venus dept.

Space 137

vinces99 writes with this excerpt from the UW news service: "It might be easier than previously thought for a planet to overheat into the scorchingly uninhabitable 'runaway greenhouse' stage, according to new research (abstract, article paywalled) by astronomers at the University of Washington and the University of Victoria. In the runaway greenhouse stage, a planet absorbs more solar energy than it can give off to retain equilibrium. As a result, the world overheats, boiling its oceans and filling its atmosphere with steam, which leaves the planet glowing-hot and forever uninhabitable, as Venus is now. One estimate of the inner edge of a star's 'habitable zone' is where the runaway greenhouse process begins. The habitable zone is that ring of space around a star that's just right for water to remain in liquid form on an orbiting rocky planet's surface, thus giving life a chance. Revisiting this classic planetary science scenario with new computer modeling, the astronomers found a lower thermal radiation threshold for the runaway greenhouse process, meaning that stage may be easier to initiate." If correct, the habitable zone shrinks a bit and a few exoplanets might lose their potentially habitable status. And the Earth will leave the habitable zone in a billion and a half or so years as the Sun gets brighter.

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Mars and Venus are warnings (1)

reubenavery (1047008) | about a year ago | (#44418335)

Just think, both of those planets someday could have been very similar to our Earth.

They are our sister planets, each expressing an ultimate degree to which things can go, and with what we've been discovering recently, remarkably little 'input'.

Re:Mars and Venus are warnings (3, Insightful)

Maxo-Texas (864189) | about a year ago | (#44418389)

I think mars was doomed from the beginning but I wonder if Venus could be terraformed with some kind of aerosol cloud to shade it and reduce the thermal input.

Re:Mars and Venus are warnings (2)

mbone (558574) | about a year ago | (#44418471)

I think at sunshade at Sun-Venus Lagrange Point 1 would do the trick.

Re:Mars and Venus are warnings (1)

techno-vampire (666512) | about a year ago | (#44420511)

You do understand, don't you, that except for the L4 and L5 points all of the Lagrange points are very unstable? If nothing else, Mercury would provide enough perturbation to move something like that out of alignment. You'd need lots of reaction mass, and frequent refueling to keep anything that big in place.

Re:Mars and Venus are warnings (1)

sFurbo (1361249) | about a year ago | (#44421101)

Would the manipulating the light pressure be enough?

I assume that the shade cannot simply absorb or reflect the light, as the light pressure would push it towards Venus, so some kind of backwards spreading would be needed. Could changing the angular distribution of this be enough to correct for the pertubations, or is a solar sail far to weak for this to work? What if the pertubations were predictable?

Re:Mars and Venus are warnings (1)

delt0r (999393) | about a year ago | (#44421693)

A light enough shade it really could be enough. In fact it sounds quite doable. If you can make it big enough. Interesting fact, satellites that are orbiting a bit further out than 1000km need to take the solar pressure on solar panels into account for fuel budgets.

Re:Mars and Venus are warnings (1)

Immerman (2627577) | about a year ago | (#44422593)

You can't remain "stationary" at an L1, 2, or 3 point without station keeping, but you can orbit those points with minimal fuel consumption for orbital maintenance. The orbit is just considerably more complicated than the elliptical orbits we're familiar with.

Re:Mars and Venus are warnings (0)

Anonymous Coward | about a year ago | (#44420649)

I'm think I've realized something about the decreasing costs of solar panels reaching profitability so close to the time period when asteroid mining is becoming a thing...

Re:Mars and Venus are warnings (2)

wierd_w (1375923) | about a year ago | (#44418519)

A sufficiently large artificial satellite put at the "Venus - Sun" legrange point would put venus into a state of purpetual eclipse, would/could mechanically shade the planet from solar high velocity particles, and serve as a useful space based power station for the planet. (I am thinking something like a great big sheet of metal impregnated mylar, with a weighted rim, spread open and stabilized using centrepital force. Its orbital relationship with venus stabilized using reaction wheels. For space based power, use thin film PV instead of mylar. For cosmic ray deflection, use the power generated to drive a large electromagnet, and incorporate the ambient plasma from the sun into the design to inflate the field.)

Totally the thing of science fiction though. Even if you eclipsed the whole planet, it would take ages for it to cool off.

Re:Mars and Venus are warnings (2)

pauljlucas (529435) | about a year ago | (#44418549)

Totally the thing of science fiction though. Even if you eclipsed the whole planet, it would take ages for it to cool off.

You'd also have to get rid of all the excess atmosphere somehow so a human on the surface wouldn't be crushed like a grape.

Re:Mars and Venus are warnings (2)

Chrontius (654879) | about a year ago | (#44418565)

Send it to Mars, I hear they're short on air over there.

Re:Mars and Venus are warnings (0)

Anonymous Coward | about a year ago | (#44421939)

Open a portal on venus, take the portal gun and open the other end on mars. Problem solved.

Re:Mars and Venus are warnings (2, Interesting)

Charliemopps (1157495) | about a year ago | (#44418667)

Who says you have to live on the surface?

Re:Mars and Venus are warnings (0)

Anonymous Coward | about a year ago | (#44419581)

if you're going to live in expensive structures why not stick to space stations in space? At least you won't be stuck in a gravity well and you can also maintain a 1 g environment.

Re:Mars and Venus are warnings (2)

KalvinB (205500) | about a year ago | (#44419825)

Gravity

Re:Mars and Venus are warnings (1)

MozeeToby (1163751) | about a year ago | (#44420139)

When the atmosphere is so dense that a pleasant nitrogen oxygen mix at is a lifting gas gravity isn't as much of a problem as you might expect. And since you're airborne you neatly get around the problems associated with Venus's very long day, and you can map/explore most of the planet just by letting the winds take you where they will. Not to mention that there are elevations with approximately 1 atmosphere of pressure and comfortable temperatures too, and if your dirigible springs a leak you have equal pressure inside and out so your lifting gas doesn't escape at more than the diffusion rate.

In fact other than Earth, 50 miles above the surface of Venus is the most pleasant environment in the solar system, you could stroll outside with modified scuba gear.

Re:Mars and Venus are warnings (1)

lxs (131946) | about a year ago | (#44420785)

When the atmosphere is so dense a nitrogen oxygen mix is VERY pleasant [wikipedia.org] but not for long.

Re:Mars and Venus are warnings (2, Interesting)

Anonymous Coward | about a year ago | (#44418719)

You'd also have to get rid of all the excess atmosphere somehow so a human on the surface wouldn't be crushed like a grape.

Why? As temperature drops, you liquify and solidify lots of the atmosphere.

Anyway, the project, if put into effect today, would take thousands of years to accomplish. With our 4-year-election-plans, we can't even handle global warming on our planet, never mind terraforming another!

Re:Mars and Venus are warnings (1)

wierd_w (1375923) | about a year ago | (#44418777)

Depending on how long you are willing to wait, and how aggressively you are eclipsing the planet, the sunshade will eventially do both:

At some point, the mean surface temperature will drop to the freezing temperature of carbon dioxide, and the atmosphere will crystallize, then snow out onto the surface, reducing surface pressure.

Again, if you have a million years or more you can spend servicing the reflector, and twiddling your thumbs. ;)

Re:Mars and Venus are warnings (2)

Shavano (2541114) | about a year ago | (#44418821)

If you could cool the planet, the atmosphere would condense to liquid except for the lighter gases.

Re:Mars and Venus are warnings (2)

wierd_w (1375923) | about a year ago | (#44419175)

The problem is that the venusian atmosphere is mostly CO2, with some anhydrous sulfuric acid thrown in.

At greater than 200psi, and warmer than 70F (metric users can suck it. I live in the US. I don't see you guys helpfully giving imperial units on your posts! Meh! [/silly faux bitching] instead, enjoy this helpful link. [wikipedia.org] ) CO2 becomes a supercritical gas. With no meniscus, the atmosphere will still ascend very high above the surface, and be too hot to condense. Items on the surface will still be "crushed like grapes"

You have to wait for the atmosphere to literally start to freeze for venus.

Re:Mars and Venus are warnings (2)

KingMotley (944240) | about a year ago | (#44419491)

Imperial unit have no business in science, and I live in the US.

Re: Mars and Venus are warnings (0)

Anonymous Coward | about a year ago | (#44419525)

doesn't matter. article dude thinks venus's atmosphere is filled with steam.
there's no metric conversion we can blame on that.

Re: Mars and Venus are warnings (1)

wierd_w (1375923) | about a year ago | (#44419543)

Who what?

I said it was CO2 with anhydrous sulfuric acid mixed in! How do you get "steam" from that!?

(Boggled mind!)

Re:Mars and Venus are warnings (1)

wierd_w (1375923) | about a year ago | (#44419561)

Can you not recognize a joke when you see one?

I knew "off my head" what the imperial transition zone was, since I work in aerospace, and it is useful as an industrial solvent and coolant. Much like many european posters are too lazy to be arsed to look up imperial numbers for things off the tops of their heads, I was too lazy to do the same in the inverse direction. I did however, link to an informative article on wikipedia that gives the metric values for the transition point, assuming you aren't one of those TL;DR types.

I make light of this laziness, and wrapped it in humor.

Your reaction is stilted and humorless.

Re: Mars and Venus are warnings (0)

Anonymous Coward | about a year ago | (#44422429)

I'm sorry, 10 years ago I would have caught it, but there are so many trolls here now that can't read, write, edit or think anymore it is hard to tell.

You said you work in aerospace, that is pretty cool. You didn't happen to work on software for the Mars climate orbiter did you Mr imperial unit science guy?

Re:Mars and Venus are warnings (1)

Rockoon (1252108) | about a year ago | (#44419819)

SI units have no business in science, either, and I live in the US too.

Re:Mars and Venus are warnings (0)

Anonymous Coward | about a year ago | (#44420829)

And for those of us who are still using a real computer, here's the link for real computers. [wikipedia.org]

(Can't they provide one page suitable for both devices? I always thought that was the fucking point of HTML!)

Re:Mars and Venus are warnings (1)

lxs (131946) | about a year ago | (#44420763)

Deep sea divers don't get crushed like a grape. They do get nitrogen in their bloodstream if they breathe regular air and the bends if they decompress too quickly.
So we "only" have to create a helium/oxygen atmosphere and good decompression facilities in the spaceports and life on Venus can be a reality. Everyone there will talk like ducks, but that's a small price to pay for interplanetary colonization!

Re:Mars and Venus are warnings (1)

I'm New Around Here (1154723) | about a year ago | (#44421997)

Wait a second!!

Venutian ducks can talk??

Actually, I didn't even know Venus had ducks.

Re:Mars and Venus are warnings (1)

jcr (53032) | about a year ago | (#44419153)

A sheet big enough to make a difference in Venus' insolation, parked at the LeGrange point, would tend to get pushed away from the sun by the solar wind acting on all that surface area.

-jcr

Re:Mars and Venus are warnings (4, Interesting)

wierd_w (1375923) | about a year ago | (#44419227)

That's why you put it "sunward" of the lagrangian point, so that it wants to fall into the sun, but is pushed out of the well by the solar wind. ;)

(Exactly where that would be depends on the specific impulse of the solar sail effect, and the mass of the reflector. Since both are hypothetical, I can't really give specifics.)

Re:Mars and Venus are warnings (1)

delt0r (999393) | about a year ago | (#44421705)

The solar wind won't push much at all. Light pressure however will be quite substantial.

Re:Mars and Venus are warnings (2)

DrFalkyn (102068) | about a year ago | (#44420039)

Venus already has a really effective 'shade' - the bond albedo (percentage of light from the sun it reflects) is 0.9 (90%). Compared to ~0.3 for Earth

http://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html [nasa.gov]

Venus is so hot at the surface mostly because the atmosphere is incredibly dense at the surface (93 times earth). In geneneral, as pressure increases in a planets troposphere, so does temperature. If you go deep enough into the gas giants (even Neptune), you will find very hot temperatures, at high pressures.

On Venus at 1 bar pressure, the temperature is actually not that far off of Earth http://www.datasync.com/~rsf1/vel/1918vpt.htm [datasync.com] - (about 50 C = 122 F), hot, but not unmanageable if we could somehow put a floating colony there. You would have to seal the habitation anyway because the atmosphere is about 95% CO2.

Re:Mars and Venus are warnings (1)

wierd_w (1375923) | about a year ago | (#44420653)

Another fun fact:

Total quantity of nitrogen gas in the venusian atmosphere is comparable to total quantity of nitrogen gas in the earth's atmosphere. The Venusian atmosphere is simply MUCH denser, and the nitrogen is diluted VERY heavily with CO2.

(Meaning, if you used a compressor and condenser on a "balloon city", you could extract the nitrogen lifting gas by compressing and freezing the CO2, and then dropping it over the side as dry ice. This assumes that the balloon city is floating at 1bar pressure elevations. This is conveniently also above the sulfuric acid cloud tops, meaning sulfuric acid concentrations will be lower.)

That temp is NOT caused by pressure. (0)

Anonymous Coward | about a year ago | (#44421187)

There is nothing to allow the heat that would be radiated from a body at that high a temperature from leaving if it were only air pressure making the heat. Indeed for Venus, at a height where the air pressure is 1 bar, the temperature is still vastly higher than the earth's surface temperature. If it were pressure making it hot, that would NOT be the case,

The air pressure and the gas law give you the lapse rate. THAT IS ALL IT GIVES YOU.

The temperature at "Top of Atmosphere" is made from the radiative balance between incoming radiation and the outgoing flux being in equilibrium.

The gas law then gives you the temperature profile when at that equilibirum.

And if you have a large atmosphere to go through before getting to the ground, you will get high temperature (because that is the temperature at TOA, plus the lapse rate times the distance you had to drop) and high pressure (because pressure is just the weight of all the gas above you).

93bar isn't the cause of the high temperature. The high temperature at TOA is the cause of it.

Re:Mars and Venus are warnings (2)

InfiniteLoopCounter (1355173) | about a year ago | (#44421297)

I think mars was doomed from the beginning but I wonder if Venus could be terraformed with some kind of aerosol cloud to shade it and reduce the thermal input.

I think that an answer to that requires some background. Venus has already lost most of its water to space due to a combination of things. Atmospheric sputtering due to the small magnetic field because of slow rotation rate (thought to be caused by an early collision with a proto planet early on) continues to carry along with the solar wind away lighter molecules like water and helium. Venus being closer to the sun doesn't help it either.

This documentary [youtube.com] shows how the earth was formed and also gives the current leading theory on how the water got here (and on venus and mars) -- that is that as jupiter and saturn were finding a stable orbit around the sun they caused many far out icy asteroids to come in a collision course with the inner planet in a bombardment that carried water to the surface of these planets.

So we would need to speed up the rotation of venus or smack it with big highly magnetic rocks from space to simulate a magnetic field, as well as causing icy asteroids to smash into it to make up for the lost water before we could try fun things like GM bacteria that eat sulphur. Any light compound in the atmosphere would be stripped away from a coronal outburst of solar activity and wouldn't last that long.

Re:Mars and Venus are warnings (1)

sabbede (2678435) | about a year ago | (#44422339)

How about a cloud of nanites? Mars is not practically terraformable, what with it being too small to retain an atmosphere, but Venus clearly can. So, develop nanites. Then develop nanites that can catalyze the atmosphere into something a bit tastier than sulphuric acid, using the ambient temperature to power the process. Two birds, one stone. Make them shiny, and they can also be used to reflect away incoming solar energy, or make them black and they can eat it. Now clearly I don't know if the reactions involved are endo or exo thermic. But hey, we can always have our nanites fire photons off world if we need to dump more heat.

Who the fuck cares ? (-1)

Anonymous Coward | about a year ago | (#44418443)

By the time planet Earth become as dried up as Mars I will be long dead

Who the fuck cares ?

Plus... it's nice to eradicate the human race anyway - there are just too many such vermins on this planet anyway

Re:Who the fuck cares ? (3, Interesting)

Yomers (863527) | about a year ago | (#44420197)

I can try to explain why. So far only known life form is our carbon based, situated exclusively on planet Earth - it includes every living organism on Earth, from amoeba to whale. We do not know it for sure, but it is possible (but unlikely) that it is the only life form existing in the universe. More likely is that life is like a sparkle in time in space - that there were (insert arbitrary large number) of life forms before us, and will be even more after us, but on cosmic time scale life expectancy of average life form is very small, so most of time/space is kinda lifeless and boring, and, most important of all, lacks an observer.

It's easy to think about observer as about god - it's something that everybody have or it lives inside everybody who's alive, it does not include any part of personality, it does not have any properties at all - so everybody have the same observer, or, you can say, it's one for everybody. If you think about it this way - it does not die after your death, so it makes you almost immortal - if you define 'me' such it does not include your personality, which I believe is right - as personality is just a sum of your genes and previous life experience.

So, what can be our purpose in life, and what can be the purpose of a humane race? Based on above I believe it should be protecting and expanding areal of carbon based life form. This runaway greenhouse scenario will end up with earth without liquid water on a surface - it can possible kill all life as we know it, so we should try to prevent it, even if it will happen after our personal deaths. Anyway, on a long enough time line, chances of survival of life on planet Earth drops to zero - so I believe we should do what we can to extend life, not necessary humans - maybe just a seeds from which evolution can begin - to as many planets as we can.

Re:Mars and Venus are warnings (1)

jacekm (895699) | about a year ago | (#44418707)

Actually Venus and Mars temperatures correlate very well with distance from Sun.

Re:Mars and Venus are warnings (0)

superwiz (655733) | about a year ago | (#44418907)

Based on what evidence do you say that they could be in the very narrow habitable range of all the necessary parameters? And what makes you think that they are a warning of any sort? AGW hysteria is premised on lack of understanding of the heat equation. It's biggest skeptics are physicists. It's biggest proponents are Hollywood actors and politicians. If you disagree, do tell why the heat equation doesn't apply all of a sudden. If you can't, then stop spewing bull shit.

Re:Mars and Venus are warnings (1)

reubenavery (1047008) | about a year ago | (#44418931)

"All the necessary parameters"? The "Heat Equation"?

You can't be serious.

Re:Mars and Venus are warnings (0)

superwiz (655733) | about a year ago | (#44418957)

I am serious. Are you? Put up or shut up. Explain why you think the heat equation doesn't apply. Or shut the fuck up.

Re:Mars and Venus are warnings (1)

reubenavery (1047008) | about a year ago | (#44419165)

Despite the straw man you are so desperately clinging to, the "Heat Equation" describes a region far greater than those of we three planets.

Re:Mars and Venus are warnings (0)

superwiz (655733) | about a year ago | (#44419287)

So you admit that you have no idea what you are talking about. Good. Thought so.

Re:Mars and Venus are warnings (1)

Anonymous Coward | about a year ago | (#44420049)

No, they may not be valid "warnings" but that does not affect global warming. Changing the composition of the atmosphere with gasses which have different infra-read absorbance will have an affect on surface temperature, or do you think basic physics does not apply hear? Science is specialised I would trust a quantum physicist, for example, almost as much as my grandfather(who has no such knowledge) to be able to come up with valid understanding of the climate. If you as a physicist wish to look for like-minded group for support you need not just some random physicist but someone that has done the work to study the field in full.
like this guy-
https://en.wikipedia.org/wiki/Richard_A._Muller
who got funding from the notoriously pro oil Koch brothers to study the climate, because he thought the climate moddles where wrong and despite his best efforts just ended up confirming them see -
https://en.wikipedia.org/wiki/Berkeley_Earth_Surface_Temperature
for more details, or google his name....

Re:Mars and Venus are warnings (0, Insightful)

Anonymous Coward | about a year ago | (#44419157)

Well, when the next warmist story appears and another warmist tries to claim "nobody is suggesting the destruction of the planet what is wrong with you people" I will point out you and this story.

Needs more doomsday. (4, Funny)

Anonymous Coward | about a year ago | (#44418345)

I don't know about the rest of you, but I found the last two lines of the summary to be quite anticlimactic. Where's the fear-mongering?

Re:Needs more doomsday. (4, Funny)

VortexCortex (1117377) | about a year ago | (#44418683)

I don't know about the rest of you, but I found the last two lines of the summary to be quite anticlimactic. Where's the fear-mongering?

Well, it seemed pretty terrifying to me. I'm not sure what kind of plans you've been making, but this significantly moves up my time tables. Now we'll probably have to completely abandon Earth instead of preserving any as a museum for the origin of life. Well, at least we can take the gene sequences...

Now it'll be much more of a smash and grab to get as many resources and mechanizations manufactured from the asteroid belt before we bolt for a new star-system. All but the first few percent of the plan will have to be re-calculated! Finding a younger destination star means taking a bigger risk with its instability, or planning an additional interstellar hop to last out the rest of the 4 billion years till the Andromeda Galaxy merges with this one. I mean, of course revisions are planed and there's some uncertainty to iron out as the future nears, but now Everything is Gorked! It might just turn out to be a complete cut and run to drift the nearest nebula and suck up the frigging dust dregs!

Re:Needs more doomsday. (1)

TheLink (130905) | about a year ago | (#44419691)

It would be terrifying if you were actually an "Immortal" who can't die and yet does not have enough power to create universes or do other things to actually enjoy Eternity.

Being stuck on a planet for billions of years till its sun blows up is not going to be pleasant especially if you can't die and you can't escape. After that you'd probably be stuck in space for a long time - which might be even worse.

Might be fine if you have really good Immortal friends to be stuck in the same "boat" with... Not sure how many times you can laugh at the same jokes though ;).

Re:Needs more doomsday. (0)

Anonymous Coward | about a year ago | (#44421375)

So if there were a bored god out there(or even 3), would that make us like The Sims or avatars in an RPG?

I'll read TFA right after I turn up the AC! (0)

Anonymous Coward | about a year ago | (#44418359)

I'll read TFA right after I turn up the AC!

No problem... (2, Insightful)

Black Parrot (19622) | about a year ago | (#44418381)

so long as we aren't responsible for it?

Re:No problem... (1)

phantomfive (622387) | about a year ago | (#44419037)

so long as we aren't responsible for it?

So long as it won't happen in the next million years....

Earth also has the potential (1)

WoOS (28173) | about a year ago | (#44418391)

At least according to the abstract of the research paper (couldn't read the paper itself) if Earth is brought into the hot moist athmosphere state, that state would maintain itself. From the abstract (emphasis mine):

Therefore, a steam atmosphere induced by such a runaway greenhouse may be a stable state for a planet receiving a similar amount of solar radiation as Earth today. Avoiding a runaway greenhouse on Earth requires that the atmosphere is subsaturated with water, and that the albedo effect of clouds exceeds their greenhouse effect. A runaway greenhouse could in theory be triggered by increased greenhouse forcing, but anthropogenic emissions are probably insufficient.

So we will probably not manage to terraform Earth into Venus just by continuing CO2 emissions. But maybe if the Vogons [wikia.com] help a bit ....

Re:Earth also has the potential (-1)

Anonymous Coward | about a year ago | (#44418545)

seriously folks, the much more pressing and immediate problem is that overpopulation. if you insist that 'global warming' is our doom, consider this: if earth's population was reduced by half (gradually), the amount of CO2 emissions would also be cut by half.

now, i'm not saying the earth will be uninhabitable within 100 years. i'm saying it will be a giant shithole in 100 years...unless we reduce our birthrates and resource consumptions.

Re:Earth also has the potential (3, Interesting)

Namarrgon (105036) | about a year ago | (#44418845)

The two are not linked. If we move off fossil fuels, our net CO2 emissions are cut to virtually zero, regardless of population (in fact, increased population acts as a carbon sink) or energy usage. Given enough cheap, carbon-free energy to distill seawater and power hydroponic stacks, we can support a far larger population if required.

Then all we have to worry about is excess waste heat [utexas.edu] , which will be a huge problem in 300-400 years. Though limiting ourselves to solar-derived energy can help a lot here.

Re:Earth also has the potential (1)

shutdown -p now (807394) | about a year ago | (#44418883)

if earth's population was reduced by half (gradually), the amount of CO2 emissions would also be cut by half.

Only if you reduce it evenly throughout all countries.

Re:Earth also has the potential (0)

Anonymous Coward | about a year ago | (#44419461)

At least according to the abstract of the research paper (couldn't read the paper itself) if Earth is brought into the hot moist athmosphere state, that state would maintain itself. From the abstract (emphasis mine):

Therefore, a steam atmosphere induced by such a runaway greenhouse may be a stable state for a planet receiving a similar amount of solar radiation as Earth today. Avoiding a runaway greenhouse on Earth requires that the atmosphere is subsaturated with water, and that the albedo effect of clouds exceeds their greenhouse effect. A runaway greenhouse could in theory be triggered by increased greenhouse forcing, but anthropogenic emissions are probably insufficient.

So we will probably not manage to terraform Earth into Venus just by continuing CO2 emissions. But maybe if the Vogons [wikia.com] help a bit ....

Partial CO2 pressure has been much, much higher in the past and a stable, permanent runaway steam atmosphere has not occurred on earth.

CO2 alarmists pointing to Venus as a warning seem to forget that it is much closer to that big furnace, and that its composition, among other parameters, is widely different.

Fearing that earth could shortly turn into Venus is as silly as fearing that it would become a second Jupiter.

Re:Earth also has the potential (2)

polar red (215081) | about a year ago | (#44420503)

CO2 alarmists pointing to Venus as a warning seem to forget that it is much closer to that big furnace, and that its composition, among other parameters, is widely different.
Fearing that earth could shortly turn into Venus is as silly as fearing that it would become a second Jupiter.

It doesn't have to be that scenario to be a big problem. just the melting of all the ice on earth alone would be a 70 meter problem.

So you believe the sun has no effect???? (0)

Anonymous Coward | about a year ago | (#44421211)

Because in those days where the CO2 content was much higher, the sun's output was 3+% lower.

Even if we don't change the CO2 leves from the holocene optimum of 280ppm, in another billion years, we would see warming too, because the sun's output will be higher.

But you didn't read the article, did you: you read "Global Warming" and then just knee-jerked your way into denying any and all facts and scientific knowledge to protect your tiny, insignificant, pile of worthless trade agreements called "cash".

But your statement insists that the sun has ABSOLUTELY NO EFFECT on the climate and that if the sun changes output the climate of the earth WILL NOT CHANGE.

Fucking stupid is what you are. Fucking stupid.

Re:Earth also has the potential (1)

symbolset (646467) | about a year ago | (#44419931)

We don't have enough carbon to do this.

Forever is a long time (2)

mbone (558574) | about a year ago | (#44418459)

As a result, the world overheats, boiling its oceans and filling its atmosphere with steam, which leaves the planet glowing-hot and forever uninhabitable,

Well, until someone comes along and terraforms it back using a sunshade.

Re:Forever is a long time (0)

Anonymous Coward | about a year ago | (#44418699)

Say I were a mad scientist bent on destroying the world via freezing it to death.. How big of a sun shade would I have to deploy in space? Where would I deploy it?

Then again if i could deploy huge objects in solar orbit I could probably think of an easier way to destroy the world. Not to mention the thing would effectively be a huge solar sail and would get pushed right out of the solar system.

Re:Forever is a long time (1)

wierd_w (1375923) | about a year ago | (#44418963)

For earth? (Rough geometrical computation)

Where: Earth-sun lagrange point 1.

How big: at least 12628.4km in diameter. (Earth is 12756km in diameter.) Roughly the same size as the earth. This would completely shade the earth.

(Given: Earth-Sun distance == 149600000km, earth-L1 distance == 1475000km (roughly), earth diameter == 12756km)

Keeping it homeostatic against solar wind is tricky, but I would do it by putting the reflector slightly sunward of the L1 point, so that solar impulse is balanced by solar gravitation. Without knowing the mass of the reflector, I can't say how far away from L1 that would be though.

Needless to say, creating a mylar sheet "that size" would definately be newsworthy in and of itself. Shooting it into orbit unnoticed would be another amazing feat, and deploying it would be an unparalleled accomplishment.

Re:Forever is a long time (0)

Anonymous Coward | about a year ago | (#44418987)

Use the solar power to keep ion engines fired up keeping it moving as little as possible?

Re:Forever is a long time (1)

wierd_w (1375923) | about a year ago | (#44419057)

Better to put the reflector "sunward" of L1, so that it wants to fall into the sun, but is pushed out by the solar wind, and held static.

Re:Forever is a long time (0)

Anonymous Coward | about a year ago | (#44419541)

Might as well submit it to What If? on xkcd.

Re:Forever is a long time (0)

Anonymous Coward | about a year ago | (#44419693)

The positioning of this would have to be incredibly precise, as it seems that something would want to fall into the sun faster than it's going to be pushed out by solar winds.

Re:Forever is a long time (2)

wierd_w (1375923) | about a year ago | (#44419797)

One possible solution to the "space weather is erratic!" Problem, is to have the reflector positioned so that it is at "nominal" condition, but not fully deployed, and able to retract while in service.

This way if solar impulse is too low, it can deploy a little further without changing mass, and get more active surface.

Likewise, if there is a large influx of solar wind (cme or something), it can constrict itself by pulling in some of the built in tow lines embedded in the fabric to reduce its surface to match. (It would need these anyway to safely unfurl a sheet that size as it spun up with a reaction wheel.)

Add a small canister of emergency stationing propellent and a multidirectional control nozzel setup, and it could perform station keeping.

Being able to regulate its specific impulse in relation to solar intensity would make this much more feasible.

A billion years or so (1)

oldhack (1037484) | about a year ago | (#44418473)

A billion years or so should be enough for everybody.

only 22 pounds to read the actual research! (2, Insightful)

0111 1110 (518466) | about a year ago | (#44418587)

This article is so affordable. Only 22 pounds. We are so privileged to have the opportunity to read this study. Just imagine a world where such study results were just given away for free. Communism!

It really is a much better world where only paying customers have access to scientific research. It is destructive and dangerous to allow poor people access to knowledge. In that way lies anarchy! The horror. Next we'll be arguing not only that information wants to be free, but that it should be free. Cats and dogs living together and all that.

Re:only 22 pounds to read the actual research! (2)

MrEricSir (398214) | about a year ago | (#44418913)

Two of the researchers who wrote this work at NASA. Seems questionable at best to charge for research that was conducted with public funds.

How do you know your money did this? (0)

Anonymous Coward | about a year ago | (#44421269)

Because the funding at NASA is being reduced, they have to get other forms of money coming in.

Just because your taxes went on a tax break and bonus to a private company does NOT mean they should give you, a taxpayer, free and unlimited access to their documents or products. You pay for them, like everyone else.

No, you want to not fund government but still demand any weak excuse not to pay for it if it's associated with the government. But NEVER a "private" company. THEY are sacrosanct. After all, you just "vote with your dollars" whereas "voting with your vote" has no power to change anything, right?

Bah, libertard idiocy makes me want to spit.

Re:only 22 pounds to read the actual research! (0)

Anonymous Coward | about a year ago | (#44419193)

You want to give UW a great big pay cut and end their reselling publicly funded research, I'm all for it. Overpaid gentry liberal academics could use a healthy pay cut.

Re:only 22 pounds to read the actual research! (1)

John Bokma (834313) | about a year ago | (#44419243)

Just email the author(s) and ask for a copy for personal research. Has been working for me, so far.

Re:only 22 pounds to read the actual research! (0)

Anonymous Coward | about a year ago | (#44419251)

You really should have done the whole Bill Murray shtick from Ghostbusters, "and all that" is so anticlimactic :(

Re:only 22 pounds to read the actual research! (1)

afxgrin (208686) | about a year ago | (#44419755)

You can probably walk into any major university, find the library and do a scholar.google.com search for a very large percentage of all peer reviewed published research. Then print it off (or save to USB key), and leave, without paying anything.

The library itself might be worth looking at as well, I'd check out the scientific review collections that people hand picked and placed together to provide a coherent, broad overview on a particular subject. I probably should go more often myself.

Sure it's not convenient but it is there available to the public. If you can't do it yourself maybe getting in contact with someone who has access would help. I can login to an old university account and get journal access still.

Re:only 22 pounds to read the actual research! (1)

ph0rk (118461) | about a year ago | (#44421721)

That is how scientific publishing is structured. Don't blame the authors, they're mostly incapable of fighting the system without sabotaging their careers.

what about weather dynamics? (3, Interesting)

khallow (566160) | about a year ago | (#44418619)

What puzzles me is the absence of discussion of rain storms. These transfer a lot of heat to the upper atmosphere where it is radiated to space. They also pump energy into wind, increasing the circulation of air and increasing the heat loss from those convection effects.

Also, I gather the relative heating depends on the spectrum of the star to some degree. I gather there's some degree of transparency of water to the lower frequency UV so a bluer star with the same energy influx might have a bit more energy penetrate the atmosphere than a redder star.

whoa wait, it's not climate change??? (1, Insightful)

Anonymous Coward | about a year ago | (#44418769)

"And the Earth will leave the habitable zone in a billion and a half or so years as the Sun gets brighter"

There, you said it, has nothing whatsoever to do with "climate change" here on earth, it's all the S-U-N!!! ;)

Re:whoa wait, it's not climate change??? (3, Funny)

I'm New Around Here (1154723) | about a year ago | (#44419179)

Earth says: "I didn't leave the habitable zone. The habitable zone left me!"

Sharks with Lasers (0)

Anonymous Coward | about a year ago | (#44418783)

If I could just make an eye of carbon, like on Jupiter and then just float it around burning all those people.. I meant to say ants. Actually yeah, I'm going outside right now for some carbon terraforming pzzt pzzt pew pew

venus the new las vegas. (0)

Anonymous Coward | about a year ago | (#44418785)

everybody knows that there is alien spaceship hanger below the venusien surface. the ships have been pre-programmed to a destination in the asteroid belt (where a even bigger hanger of alien ships resides) : )

every one wants to drive a hummer (-1, Troll)

Mister Liberty (769145) | about a year ago | (#44418793)

so hum your way to extinction and let the rest of us
alone and just laugh about your small dicks.

Re:every one wants to drive a hummer (0)

Anonymous Coward | about a year ago | (#44419115)

One Thing Computers Already Did: Descend From Apes.

Patwalled (1)

mcgrew (92797) | about a year ago | (#44419097)

I wish I could read the actual studies. Most are paywalled. Can we change this? I want to learn!

Re:Patwalled (1)

symbolset (646467) | about a year ago | (#44419941)

Talk to Aaron. He downloaded a lot of these.

First I've heard... (0)

Anonymous Coward | about a year ago | (#44419185)

...of steam glowing hot...man, science is not like it was when I was young.

Re:First I've heard... (2)

wierd_w (1375923) | about a year ago | (#44419325)

Actually, steam should glow spectacularly in the far IR spectrum.

Clearly, you are unfamiliar with blackbody radiation, and with what the primary absorption/emission bands are for water vapor.

Who cares (1)

p51d007 (656414) | about a year ago | (#44419351)

humans on earth won't be around in 50 billions years anyway. At the rate we're going, humans will die off in about a few thousands years anyway.

Re:Who cares (1)

black3d (1648913) | about a year ago | (#44419743)

To be fair, they said a billion and a half years, not 50 billion years. Although the chance of us being around in a billion years is non-existant. Certainly not in our current form. We'll have either evolved by then (look how far we've come in the last 100,000 years alone) or run ourselves into extinction.

I'd say we have quite a bit longer than 'a few thousand years', though. We've been around as mature homo sapiens for more than a few thousand years already. Oh sure, we may manage to wipe out "most" of us through war or pestilence, but some folks will manage to hang on.

However, if we manage to overcome, then in a billion years there's no expectation we'd still be stuck here on Earth. Also, by then Mars would be right smack-dab in the middle of the habitable zone.

Re:Who cares (0)

Anonymous Coward | about a year ago | (#44421469)

There's always the unknown factors, 100,000 year events like the Earth's magnetic field flipping, Supervolcano eruption, or a large interstellar asteroid strike.
Mass extinctions are likely, and creatures that can hibernate for years are a lot hardier than complex mammals that require specific survival conditions.

If it didn't happen during dinosaur times (0)

Anonymous Coward | about a year ago | (#44419747)

It won't happen five hundred years from now or even longer. We're not adding new carbon to the atmosphere.

Re:If it didn't happen during dinosaur times (0)

Anonymous Coward | about a year ago | (#44420905)

Reading comprehension: Fail.

Actually I guess you didn't even read anything but the trigger word "Greenhouse" in the title.

This is not about AGW. This is about the habitable zone in planetary systems. And no, nobody expects the earth to leave that zone in the next five hundred years.

Pick your poison (1)

WinstonWolfIT (1550079) | about a year ago | (#44421173)

While this may be true, I'll take warding off the next ice age in 10,000 years if global warming is the cost. Between the two, higher sea levels is a no-brainer.

Mars? (0)

Anonymous Coward | about a year ago | (#44421827)

Any chance Mars will be back in the habitable zone by the time Earth leaves it?

might be easier.. (0)

Anonymous Coward | about a year ago | (#44422243)

"might" is linguistic psyop meant to imply more than what is said

"It might be easier than previously thought..." could be equivalently stated as:
"It might Not be easier than previously thought..."

or if you want be more accurate:
"We still dont know how stuff really works but that wont stop us from implying all sorts of things that we cant prove..."

Ruh roh raggy (1)

eyenot (102141) | about a year ago | (#44422383)

I think it's a , it's a , gh-gh-gh-greenhouse gas global warming monster!

Quick you assclowns! Get into the mystery hybrid mobile! *Vrrrrooooomm*

I think it's still chasing us! How could that be? We left the Hubbert peak way behind with our super efficiency!

Uh-oh, if my calculations are correct, the only people our efficiency was helping was the *gulp* big oil companies themselves.

*poof* The monster appeared in the mystery hybrid mobile! The monster tore its own mask off!

"Will you kids shut the **** up? I'm not global warming I'm your planet's inevitable heat death. In, like, a billion years."

GET HIM! *pow* *kbam* *kick* my glasses!

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