Marsian Oceans

Palomar · 2002-11-11 12:48:27

Byron saith: "However, the discoveries of the scientists and researchers on Mars are legion...while no evidence of life has been discovered, Mars has found to be an even more dynamic world than we could have ever imagined, and there is enough water under the surface to fill up entire oceans."

*I'm bringing this quote over from Byron's "Fun and Games, 3 hypothetical Martian settlements" post.

If I remember right, Mars' land mass is roughly the size of all of Earth's continents shoved together....?

If the powers that be [whoever they turn out to be, and I'm not interested in speculating on that issue in this thread] decide to go ahead and terraform "to the max," aren't they going to have to be careful with how large bodies of water become? I tend to think land will be considered more of a premium than water, once water becomes permanently available in liquid form. Besides, we touched on the possibility of introducing marine life into oceans/seas months ago here [I can't recall which thread], and that itself would be a Herculean and perhaps nearly impossible feat; thus, there won't [for a long time anyway] be any need for huge expanses of water in which to house whales and the like.

I looked at an online topographic map of Mars; unfortunately it was just one "side" of the planet showing. There are huge mountain ranges of course; on this particular topographic map, the flatter areas look to be toward the south in the photo [if that's south -- directions weren't given either]. So not only will terraformers have to take those huge mountain ranges into consideration, they'll also have to plan for how large oceans/seas/lakes are...IF something like that is "planable." Once the weather intensifies on Mars with further clouds, humidity, and etc., it could develop into a much more daunting task...no doubt a few settlements/colonies could be swept away as the planet changes.

Just some thoughts.

--Cindy

Josh Cryer · 2002-11-11 13:57:41

Yeah, I like that part of Byron's post the best. Mainly because that's what the evidence is pointing to! Mars, in all likelihood, once had a very large ocean, and it's probably still there, either frozen in the regolith, or in subsurface reservoirs. But I don't think we should dispair, as there is enough evidence to suggest that it couldn't really cover the whole planet if it all was melted.

This is a nice, worldwide topographic map of Mars: http://ltpwww.gsfc.nasa.gov/tharsis/Mar … from_MOLA/

I think it's fairly safe to assume that if such an ocean were to be melted, it wouldn't fill more than just the blue, smooth, areas. Remember, as a volume increases, you have to take into consideration surface area. It would take increasing quantities of water to flood the whole planet! It's been speculated that if Mars was a smooth ball, it would be covered in water several meters high.

Those who decide to terraform will obviously have to take into consideration how much water is there. But we can't know exacts until we actually do it and let Mars' nature reach its own little equilibrium. I think we can be close though. Close enough to be able to warn low-land settlers of the impeeding water and so on. I personally don't see land as big deal as others. There's no reason we can't live on the water! Or under the water...

But honestly, I don't think we can start a terraforming process in which only small quantities of liquid water exist (unless they were inside domes- but I wouldn't call that terraforming). Once we start, it'll run away with itself until the planet calms in its own new weather cycles.

I think introducing whales is only necessary if we want the aquatic sea life to be as robust as possible. Aging plants would be eaten as the whale scoops up plankton, making room for newer healither plankton. It would be no feat to introduce plankton, though.

Byron · 2002-11-11 16:19:14

Glad you brought this up, Cindy...

I have a quite colorful topgraphical globe of Mars I ordered from Sky and Telescope a while back...and it show quite clearly the high and low areas of the Red Planet. Of course, the lowest areas are a deep blue, trending towards red for the highest elevations. If one drew an imaginary line at the -2km elevation contour (the point where the blue areas begin), you can quite easily imagine a very large northern ocean covering close to 50% of the entire nothern hemisphere, plus the massive and very deep Hellas basin. Of course no one knows if there is enough water to make an ocean that big, but just casually glancing at the globe, it is not difficult to imagine a Martian ocean being there at one time in the distant past...as smooth and flat as those 'blue' areas are, not to mention the apparent drainage basins leading into those areas, I would have to say there were oceans at one time in the distant past, and if that is indeed the case, there is no reason to think that terraformers couldn't restore Mars to its former, wet state.

Even with the large northern ocean and a flooded Hellas, most of Mars would still be dry land, and any land that is located between zero (mean elevation) and minus two kilometers (likely elevation of a past / future sea level) would surely the most desirable areas to live, as the air would the the thickest and warmest there, especially in the equatorial regions. One thing I would ask of the terraformers, however, is to find some way to preserve the great Valles Marineris..it'd sure be a shame to see that magnificant valley get flooded out! Perhaps a huge dam could be built at the eastern end of Marineris, leaving a nice, wide swath of dry land that extends up to five km below the datum, which would make it one of the first human-habitable areas if a terraforming effort was indeed undertaken.

As for people settling on Mars before any terraforming effort is undertaken, it'd probably be a good idea not to build a permanent settlement in the lower elevations of the northern hemisphere...as we all know, preventive measures tend to work the best in these type of situations!

B

Shaun Barrett · 2002-11-11 19:15:54

Hi everybody!

I have the same globe of Mars as Byron, and it's one of my prize possessions!
Sometimes I just sit and study it and try to imagine the forces that shaped it over the eons. The fact that the northern lowlands are coloured blue is very evocative of an ocean, and it's not at all difficult to visualise how Mars will be when we recreate such a body of water on the surface.
I really recommend that anyone with more than a passing interest in Mars should get this globe. It's colourful, topographically accurate, endlessly useful when you need to visualise a certain area under discussion, makes a nice decorative addition to a shelf or desk, and makes a great talking point when people ask what your interests are! (And no, I don't have shares in 'Sky and Telescope'! I just love this globe.)

As I mentioned in another post a long time ago, huge areas of Mars, as depicted on this globe, look 'smeared'. They almost look like the aftermath of a wave on a child's sand castle. It sounds incredible, but you definitely get an intuitive feel for how much water has existed on Mars and the staggering torrents of it which must have engulfed and reshaped great swathes of the surface.
You simply can't examine this globe without 'knowing' in your gut that Mars was a very watery world.
There's no doubt in my mind that large oceans have existed there in the past, possibly for very long periods of time, and possibly intermittently, I don't know. And great meandering rivers must also have graced the scenery at some stages in Martian history.
The fact that crater counts and the apparent lack of erosion evident in so many areas seem to contradict the concept of a surface hydrological cycle for extended periods (perhaps even including significant precipitation), doesn't deter me. The simple visual evidence that Mars was once warm and wet is, to me, too strong. I'd rather believe that our interpretation of the cratering epochs and rates of erosion is somehow flawed. We're missing something important in that regard which I'm sure, when we discover it, will suddenly resolve the mystery.

I agree that we'll have to be cautious about where we place population centres - a little forward planning will save having to relocate towns when the waters rise.
I've often thought about where on Mars the most popular settlement areas will be. I've always imagined the 'shores' of Ganges and Eos Chasmas, Simud and Tiu Valles, and the southern reaches of Chryse Planitia, will be the 'Mediterranean' of Mars! This region straddles the equator and boasts a whole archipelago of islands (not yet, but soon! ) which will make very desirable real estate!! Many local residents will no doubt have boats and will spend their leisure days cruising the inlets and gorges of Kasei and Ares Valles.
Two other popular spots for settlement might be the coasts of the Isidis and Hellas Seas (currently Isidis and Hellas Planitias, of course). The southern stretches of the Hellas Sea coastline will be better suited to expatriate Canadians and Norwegians, I think ... because of the weather!
There will be so many drop-dead-gorgeous places to build a home and a new life that it's hard to even begin to cover all the possibilities.

My only regret is that I won't live to see it.

Josh Cryer · 2002-11-12 01:01:16

I think the biggest clue to the once great Martian ocean is the area around Olympus Mons! Just check out those drainage troughs!

But yeah, Byron. I agree with you, with regard to the Valles Marineris. It would probably actually prove to be wise to damn it up, since we could create tons of electricity by using hydro generators. We'd never let it fill all the way, of course. Just the bottom a little.

Palomar · 2002-11-12 12:11:35

*Thanks for the interesting responses, maps, etc.

About the Marsian northern and southern poles and ice caps: Those ice caps aren't very thick, are they? Since Earth's polar ice caps are of importance in maintaining our ecological health, what are the chances that terraforming Mars [to the extent of a breathable atmosphere and average tropical temperature of, say, 75 degrees F] would eliminate and/or greatly shrink those ice caps? Would the climate and ecological health of a Mars in the process of being terraformed be HURT by shrinkage of ice cap size, or their disappearing nearly entirely?

--Cindy

Byron · 2002-11-12 14:11:47

Although no one knows for sure, the Martian ice caps are actually pretty thick...anywhere from 1 to 3 kilometers of maximum thickness by some estimates. That's a lot of ice! Also, the caps may actually cover a larger area than is apparently visible from orbiting satellites, as dust and sand have likely covered up huge expanses of ice around the perimeter of the ice caps over the eons.

As for shrinking the ice caps, yes, in the beginning of a terraforming effort, the caps would shrink, especially the southern one, as it consists partly of CO2. However, as the atmosphere begins to thicken up and becomes wet, the average temperature of Mars would still be quite cold by Earth standards. This means that the newly released water would have a tendency to precipitate out at the poles as snow, making them bigger again. In fact, if we're not careful, the poles would turn into giant glaciers and send sheets of ice towards the equator..creating a Martian ice age..! Shaun made mention of that possibility a while back in another thread.

I guess one way to keep the polar ice caps in "check" is to spread some ice-loving black alge on the ice sheets during the summer months, which would melt back the ice accumulated during the previous winter. The biggest thing about keeping Mars ecologically balanced is management of the oceans, as they would essentially regulate the climate of the entire planet.

B

Shaun Barrett · 2002-11-12 19:05:43

Fascinating image, Josh! Thankyou.

And I think Byron is absolutely right in his response to Cindy's questions. I think there's more water in the Martian regolith than we know ... far more than even the most optimistic estimates so far made on the strength of Odyssey data. (I could be totally wrong, I suppose, but I doubt it in this case.)
Terraforming should release much of this water and establish a surface/atmospheric hydrological cycle again. The poles are never likely to be warm enough to melt the caps completely and they should actually be bigger, as Byron suggests, because of extra precipitation. Our greatest problem being controlling just how big they do get!!

As an aside, I don't know that Earth's polar caps are really "of importance in maintaining our ecological health", as Cindy phrased it.
We are in what is called an Ice Epoch at present, which is a series of ice ages separated by brief interglacials. The last ice age ended about 10,000 years ago, and we are currently at the tail end of an interglacial which is well overdue to collapse into the next ice age.
An ice epoch is defined as a period of time during which there is a permanent ice cap at either pole. For most of its history, Earth has been without permanent ice caps. A permanent ice cap at even one pole is unusual for Earth, and to have permanent caps at both poles is a rare event, probably brought about by the present arrangement of continental plates.
Certainly the removal of our polar ice caps would herald enormous climatic and ecological upheavals, which would play havoc with our comfortably predictable lifestyle. In fact, if it happened suddenly enough (which is most unlikely), much of the human population would probably die and we might well be returned to a kind of dark age of economic and scientific stagnation. But that doesn't mean Earth's ecosystem as a whole would necessarily suffer any significant long-term effects. It would simply return to a pattern more familiar to it, without the ice caps!
This is one of the reasons why I don't lose too much sleep over global warming. Earth's present cold climate is an aberration. Earth's average temperature is normally much higher than it is today and there has never been a runaway greenhouse effect. (Or, obviously, we wouldn't be here discussing it!! )
A recent study, reported in New Scientist magazine (a publication which usually toes the line as regards global warming angst), predicts that if warming proceeds according to predictions over the next 50-100 years, it will result in a 16% increase in world agricultural production ... not from higher CO2 levels, but from longer growing seasons.
Remember, we're long overdue to plunge into the next ice age in the series. A little bit of extra CO2 in the atmosphere might help to fend off what would be a far far greater catastrophe for the human race - ice sheets across most of Europe, Asia, and the continental U.S.A.!
???

soph · 2002-11-24 21:50:09

i think its a good idea to plan where we are going to "put" oceans, and launch manned missions accordingly. assuming the Mars Direct blueprint, a "town" 50-200 km within an ocean or large body of water would be ideal.

it would be harder to change things on this scale once people are in permanent, large communities, so the major terraforming should be done in the early stages of manned missions, in my view.

now, i have a question. can we control the purity of the oceans? if we can do that, large scale irrigation would be a HUGE boon to any colonies, among other benefits of pure water.

Shaun Barrett · 2002-11-25 01:18:28

Hi Soph!

I think the Martian regolith is rich in sodium chloride, not to mention other salts and minerals.
I'm no expert by any means, but my understanding is that any future Martian oceans will probably be salty, like Earth's, and no good for direct irrigation.

If there is a high water-table, though, it may be possible to obtain bore-water in some places which might be pure enough for crops. But I'm just guessing.

Bill White · 2002-11-25 14:23:58

Remember, we're long overdue to plunge into the next ice age in the series. A little bit of extra CO2 in the atmosphere might help to fend off what would be a far far greater catastrophe for the human race - ice sheets across most of Europe, Asia, and the continental U.S.A.!

What is your opinion of the salt circulation models, which suggest that warming of Greenland, Iceland and the Arctic ice cap will dump massive amounts of fresh water into the Arctic and Icelandic seas and thereby "shut off" the Gulf Stream - - > which is what stands between Britain and northern Europe and a destiny of being buried underneath gigantic glaciers?

(The Gulf Stream is warmer and less salty and flows north because the northern seas experience evaporation and the more salty and thus heavier water sinks and flows south towards the equator. These currents exist in 3-D loops. A topographical globe showing the ocean bottoms makes it obvious that the sea floor near Iceland is much higher than the sea floor at the equator.)

Uniform global warming - if the northern ice sheets stay frozen - is not really that a big deal - IMHO!

However, if the northern ice sheets melt and the evaporation of the northern seas slows and the Gulf Stream stops flowing, Britain and Europe will glaciate; world-wide CO2 emmissions would plummet once a new ice age got going - a positive feedback loop to even more glaciation; and more sunlight will be reflected back into space another positive feedback loop and thus a global ice age could plausibly arise precisely as a consequence of global warming melting these northern ice sheets.

A bit more CO2 in the atmosphere might well be the precise triggers that starts our next major Ice Age.

Byron · 2002-11-25 16:10:22

Actually, Bill, I'm a bit familiar with the oceanic "conveyor belt" theory...and the fact that the ocean's currents operate in a 3-D fashion has serious implications for the potential of sudden and dramatic climate change.

It is indeed possible that a sudden increase in the meltwater of the Arctic region around Greenland could force the Gulf Stream to "dive" under the sea before it reaches Europe, and yes, without the warming influence of the Gulfstream waters, Europe would be in the deep freeze. England, Demmark and Germany are all at the same latitude as central Canada, so it doesn't take much of an imagination to envision what would happen if the Gulfstream stopped flowing towards Europe...

As for glaciation, that would take hundreds, even thousands of years before glaciers actually rolled over the cities of Europe, but the consequences of a drastically changed climate would still be quite dire for that part of the world...especially "interior" countries such as Germany and Austria, which would have exceedinly long, bitter winters, with short, cool summers. Certainly, the economies of the northern countries would fail, leading to mass migrations away from that area of the world.

As for North America in this scenario, the main problem would be drought, as cooler Atlantic waters would limit the flow of moisture into the interior of the continent, and hardship would likely follow as well, with massive crop failures, etc. I can only imagine that the southern countries would experience a tremendous boom and become economic powerhouses as people and capital make a mad rush to the south...lol...so there would be winners as well as losers if this sort of thing would happen.

B

Shaun Barrett · 2002-11-26 02:25:55

Hi Bill!

It sure sounds paradoxical, doesn't it?! Global warming tipping us into the next ice-age!

I think the most important point is that we really don't know exactly what tips the balance, unless you subscribe to the Milankovich-cycle theory of long-term differences in the tilt of Earth's axis and the eccentricity of our orbit etc.
Atmospheric CO2 levels have gone up and down like a yoyo in the past few million years due to changes in vegetation and volcanic eruptions etc. Global temperatures have gone up and down, too, of course. But the exact mechanisms are still poorly understood, and direct cause-and-effect relationships are hard to establish because of the number of variables.

I think we need to get away from this view that the world's climate has been static and unchanging since the dinosaurs died, and that humans are the only agency that's caused any change in the atmosphere. We're not! Monstrous changes have occurred in Earth's atmosphere and climate over periods of billions of years, and many of those have happened since the end of the Cretaceous. Not one of those changes was manmade!! We weren't even around until yesterday, geologically speaking.
A long period of volcanism could commence next year and last for a million years, during which time the present levels of CO2 in the air could double or triple or quadruple. For a while, at least, global average temperatures could rise by several degrees Celsius and a significant retreat of the polar caps could occur. Whose fault would that be? Nobody's. Would life on Earth be snuffed out? Of course not.
Since reliable records were kept, over the past century or so, we've recorded a rise in the global average temperature of just 0.5 deg.C. I'm reasonably sure that there's no absolutely indisputable proof that this rise is due to manmade additions of CO2 to the atmosphere, although we are the likely culprits. But this is a non-event compared to what nature is capable of!

Regardless of what we do, it is unlikely we can keep the next ice-age from happening. The present configuration of land masses is the overriding factor in gross climate characteristics for this planet, with a virtually landlocked Arctic Ocean (very sensitive to changes in insolation) and a large, isolated, frozen continent sitting right over the south pole. We are far more vulnerable to ice-ages than to global warming, but have been lulled into a false sense of security by these past several thousand years of benign interglacial temperatures.
As I've said, for this reason I don't really lose any sleep worrying about global warming.
And since nobody has a clue how sensitive the Gulf Stream actually is to changes in the amount of fresh water melting off the northern ice cap, I haven't started worrying about that one yet either!! Every year, another scientist comes up with another plausible climate hypothesis which becomes the fashionable thing to worry about.
But the painful truth is we're not as powerful as we think we are in terms of our ability to change the climate, and we really have no idea what's going to happen next!!

Byron · 2002-11-26 06:28:03

Since reliable records were kept, over the past century or so, we've recorded a rise in the global average temperature of just 0.5 deg.C. I'm reasonably sure that there's no absolutely indisputable proof that this rise is due to manmade additions of CO2 to the atmosphere, although we are the likely culprits. But this is a non-event compared to what nature is capable of!
Regardless of what we do, it is unlikely we can keep the next ice-age from happening. The present configuration of land masses is the overriding factor in gross climate characteristics for this planet, with a virtually landlocked Arctic Ocean (very sensitive to changes in insolation) and a large, isolated, frozen continent sitting right over the south pole. We are far more vulnerable to ice-ages than to global warming, but have been lulled into a false sense of security by these past several thousand years of benign interglacial temperatures.
As I've said, for this reason I don't really lose any sleep worrying about global warming.

I find it rather refreshing that you believe the threat of an ice age is greater than global warming...how often in history has the "lone dissenter" have been the one to be right in the end?!?

There's no denying the fact that ice ages have come and gone over the past 3 million years, and one of the theories I've heard is that the ice ages first began when the isthumus formed between North and South America, which prevented the world's ocean currents from mixing and keeping the long-term climate in equilibrium... Does anyone have any opinion about this?

If an ice age does begin, I wonder if we would have centuries of "lead time" before the glaciers started moving south, or would the climate change take place suddenly, like in a decade or two? Obviously the latter scenario would have most dire consequences for mankind, as there wouldn't be enough time for adjustment to the new, colder climate.

Shaun, since you seem pretty knowledgable about this subject, do you know what the climate of Australia was like during the past ice ages?

I have this vision of Australia turning into this lush, green paradise while the glaciers cover a good portion of the northern continents...and certainly, the continent's favorable latitudes would prevent glaciers from forming there, except for perhaps in Tasmania and the Snowy Mtns.

In the past, I've often thought about what really would happen if an ice age were to occur in these times (I'm "hot" on ice ages..can't you tell...LOL)...and what the powerful, wealthy northern countries would be doing to cope with the advance of the cold and glaciers...perhaps they would just move their populations to the tropical regions, and those countries just be dammed, or would there be full-scale global warfare, ending civilization as we know it...or perhaps this would be the catalyst to spur humankind to spread out into space on a very large scale?

The things I come up with..lol...

B

Shaun Barrett · 2002-11-26 19:58:00

Hi Byron!

It's very nice of you to be so complimentary, but I can't classify myself as a "lone dissenter" by any means. It sounds great though! .... A voice in the wilderness trying to persuade the world that it's going the wrong way!!
But the fact, as in most cases, is far more mundane than the fiction. All you have to do is to read stuff from all sides of the story and treat each version with as much critical neutrality as you can muster.
There are usually several different sides to any story because the world is a complicated place. Not very much is in simple black and white. The climate is probably one of the supreme examples of this premise because it's essentially a chaotic system with countless poorly understood inputs. We like to think our complex modelling of climate characteristics on super-computers has given us an accurate insight into the climate and our influence on it. But, time and time again, our climate models, hailed as definitive when they were new, are found not to match the facts! We really aren't as smart as we think we are.
Bearing this in mind, when all the world's press and other media start screaming in unison that the sky is falling, and when hundreds of scientists start agreeing with each other that they've definitely got a handle on how Earth's climate works (for sure this time! ), I just naturally step back and say ... "Hang on a minute. There's something wrong with this picture!"
Call me stubborn, obstinate, and recalcitrant if you will!! But every time I go to the drawer in my head marked 'Experience', the files there tell me that if nearly everyone is running in the same direction, yelling and shouting, they're usually going the wrong way! I'm very wary of mobs, however eminent some of them may be.
So it's nothing heroic, I'm afraid, just down-to-Earth common sense!

In response to your question, the answer is I'm not sure how Australia would change in the event of another ice-age. What I do know is that, during the last one, many of the currently arid parts of inland southern Australia had lakes and relatively lush vegetation, which supported large tribes of aborigines in some comfort. I suppose the best guess is that the same pattern of climate would re-establish itself.

Incidentally, as far as the rate at which a new ice-age might impose itself on the world is concerned, there is at least some evidence that it would be very quick. Although it would take many centuries to build up thick ice sheets across the northern continents, some schools of thought believe the actual change-over to much lower average temperatures could occur in half a human lifetime!
If the human population were, say, 1 billion instead of 6 billion, we might just be able to cope with the enormous changes to agricultural patterns and the human migrations which would follow. But as it is, we're 'on the edge' and overstretched. Even small changes in local micro-climates are enough to disrupt the economies of whole countries. We're too vulnerable because there are too many of us.

O.K. There may be a bit of global warming going on, and maybe we're responsible for it. And it's true that you shouldn't go changing things you don't understand. But Earth isn't normally this cold anyway - it normally runs temperatures considerably higher than today's. So the chances of a runaway greenhouse event are vanishingly small ... we're not likely to turn into Venus Mark II !! And longer warmer growing seasons in most places will not be such a bad thing, even if they do occur. And I'm not at all convinced this will happen.

No. It's the next ice-age that concerns me. That's something really worth worrying about ... and it's overdue!

???

Byron · 2002-11-27 03:36:22

No. It's the next ice-age that concerns me. That's something really worth worrying about ... and it's overdue!
???

And this is why humans need to get established on Mars - NOW. If an ice age really did come along and "extinguish" the light of civilization, people on Mars could continue to carry the torch (provided that they could survive on their own).

I think everyone could rest easier if humanity were on two worlds instead of just one....

B

dicktice · 2002-11-28 13:07:26

Regarding Venus, Shaun: The comparison with Earth and threat might kind-of instructive, but its terribly slow rotation makes it an unconvincing example to use for your commendable purpose.
And Byron: Glaciation might be prevented by our own selves, spreading soot about on persistant snow accumulations to force them to melt entirely each summer. Not original, I admit...but, are we not the first humans on Earth to recognize the threat, with the capability of spreading soot from the sky to prevent the warm sunlight from being reflected back out into space-- and thus break the cycle of recurring ice-ages. We're very good at spreading dirt around, you'll admit.
Asteroid or comet impact: Now there's a real good reason for inhabiting more than one place in the Solar System!

Dorothy · 2003-01-10 05:39:56

Hello Shaun,

you state that most of the human population might die, if global warning happened fast.
There would possibly be many deaths and certainly be much misery in the course of global warming.

You also state that you don't use much sleep over global warming.

I hope you don't mean it like this.

soph · 2003-01-10 05:55:35

I think he meant he doesnt really expect global warming to occur to that degree in our lifetimes.

But I havent seen him on the board for a while, anyone know where shaun is?

Palomar · 2003-01-10 08:15:34

But I havent seen him on the board for a while, anyone know where shaun is?

*Wish I knew. I've been missing his input here! Seems he's not been with us since around the 3rd week of December.

I hope he returns soon!

--Cindy

Josh Cryer · 2003-01-10 12:27:13

Proof of global warming: CO2 insulates. CO2 is increasing in the atmosphere due to the burning of fossil fuel, something which is a man made phenomena and has only recently begun. The end.

Byron, I didn't see your post apparently when it was made, but yes, the Great Ocean Conveyor model is probably more accurate than any other. And anyone who denies that the decreased salt content in the water is some non-man made problem, is denying everything that goes into the scientific process (unless they can provide a reasonable explaination that explains warming, and water ice melting).

http://www.whoi.edu/home/about/whatsnew … imate.html

An interesting scenerio is that all of these past ice ages were caused by global warming. Volcanos which spewed out lots of gas. Oceanic plant life dying off, unable to replace the CO2 in the atmosphere with oxygen. Worldwide forest fires, or diseases. Overpopulation of animals (eating too many plants over the span of thousands of years).

Palomar · 2003-01-10 13:19:31

*Approximately how much consistent humidity, percentage-wise, would Mars have to have/maintain to induce a rain cycle?

--Cindy

Josh Cryer · 2003-01-10 13:27:58

Approximately how much consistent humidity, percentage-wise, would Mars have to have/ maintain to induce a rain cycle?

That's a hard one Cindy. I was learning about gas laws for awhile there, but I gave up after awhile. Basically it depends on how much thermal energy is absorbed, and how much evaporation occurs. Since Mars' ocean would be almost exclusively in the northern hemisphere, it's hard to imagine how it would function. Would water laden clouds even migrate to the southern hemisphere?

Shaun Barrett · 2003-01-26 02:15:47

I've just read Soph's very interesting post over at 'Acheron Labs-Life on Mars' called 'Volcanic activity on Mars'

The article Soph draws attention to, concerns a possible re-evaluation of the current wisdom on estimating the age of various regions of the Martian surface. Apparently, this may result in a complete re-think about the sequence of events in Martian history which shaped the surface over the eons.
The article appears at this site.

The reason I found Soph's post so interesting, is because it may be relevant to my first post here in 'Marsian Oceans'.
Both Byron and I have a 'Sky and Telescope' topographic globe of Mars. And we both agree that the appearance of the surface features on this globe virtually screams WATER!!
In my post, I bemoaned the fact that the currently accepted wisdom about erosional features on Mars seems to indicate that, essentially, erosion all but ceased about 3.5 billion years ago. Yet other evidence seems to show major water flows and sedimentation in more recent times, at odds with the present paradigm.

Anyway, the point is, I'm hoping that a whole new scenario for the history of Martian volatiles may come from this - a scenario which will include much more surface water for much longer periods, and into much more recent times too!!

Shaun Barrett · 2003-01-27 20:37:52

Just a brief comment on a line of reasoning which appeared earlier in this thread regarding the Great Ocean Conveyor:-

The argument was that melting of ice in places like Greenland, ostensibly caused by 'global warming' and therefore the result of manmade atmospheric changes, is altering the salinity of sea-water in the North Atlantic. The potential result of this would be to interfere with the flow of the Gulf Stream and, thus, lower average temperatures in Europe by as much as 18 deg.F.
The point of the argument is that Europe's food production could be dramatically reduced, very quickly, and that starvation and social upheaval would follow. The worst case scenario, of course, would be the progression of this calamity to a full-blown ice-age.
And all because of human-induced global warming. (I honestly don't wish to antagonise anyone, but the 'global warming movement' really does hedge its bets quite neatly. If the world is moving towards a Venus-like runaway greenhouse effect, it's global warming. If we're heading into another ice-age ... well, that's global warming, too! )

Some recent research, click here to view, now suggests that the Gulf Stream's influence on temperatures in north-west Europe has been greatly exaggerated. It looks like the Rocky Mountains in America have more effect!

My position on 'global warming' is no secret. I'm not a paid-up member of any politically motivated group or cult in this matter - I simply look at the big picture in as neutral a frame of mind as I can muster.
There is just too much we don't understand about Earth's climate to be able to formulate coherent views about whether or not human activity is having any effect whatsoever on long-term weather patterns.

This latest research calls into serious question one of our most cherished climatic models - the model which ascribes Europe's climate, unusually mild for the latitudes concerned, to the Gulf Stream. Where does that leave us?

In view of our almost total ignorance of how the climate works, how it changes, and the effect of higher or lower CO2 concentrations on temperatures, it is very obvious to me that the 'global warming movement' is based much more on ideology than it is on science.

"The sky is falling, the sky is falling!!", cried Chicken Little.

It isn't.

P.S. I strongly support any serious and sensible moves to
shift humanity away from reliance on fossil fuels. If safe
nuclear reactors are the way to go, so be it. But, ideally,
better solar energy technology is what I'd like to see
developed as soon as practicable.
I have no shares in oil companies and I'm not in love with
President Bush! But I do object to science being
prostituted for the sake of petty politics.

P.P.S. This has been slightly off-topic but could be related to
Terraforming in as much as we need to understand our
limitations as well as our capabilities when it comes to
climate modification.

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