Thread: If Ice Caps Vanished...

Polar regions today are sparsely populated, ice being lousy place to build anything and long commute to anything, location, location, location.

If ice were to melt, over 1.75 million kilometers squared would become available for mineral extraction, habitation, etc.(okay, maybe not so much agriculture) in Greenland alone, to say nothing of Antarctica, the lonely continent.

Ice has vanished from poles before in history of planet and so can be expected to do so again, so what are consequences bad and good?

The main bad consequence is an 80 metres rise in sea level. (Assuming all ice melted, including Antarctica, which is unlikely any time within the next thousand years). This would flood about 5% of all land surfaces, which does not sound much, until you realise that a very large percentage of the world's cities are within that 5%.

It is actually, far more likely that the sea level rise up to the year 2100 will be less than one metre. This will require massive expenditure on sea dykes around major cities on the coast, or inside tidal river systems, but could be done. That level of sea level rise is something humanity can adapt to. 80 metres would be more difficult, but is unlikely any time in the foreseeable future.

so what are consequences bad and good?

Higher and unequally distributed raised sea level, loss of arctic habitats and its menagerie of plants of animals or at least their withdrawal to Arctic and Antarctic mountains chains. Short of some unforeseen cause, this would take thousands of years.

Originally Posted by skeptic

The main bad consequence is an 80 metres rise in sea level. (Assuming all ice melted, including Antarctica, which is unlikely any time within the next thousand years). This would flood about 5% of all land surfaces, which does not sound much, until you realise that a very large percentage of the world's cities are within that 5%.

It is actually, far more likely that the sea level rise up to the year 2100 will be less than one metre. This will require massive expenditure on sea dykes around major cities on the coast, or inside tidal river systems, but could be done. That level of sea level rise is something humanity can adapt to. 80 metres would be more difficult, but is unlikely any time in the foreseeable future.

Yes, even in Greenland population is concentrated near coasts, for multiple reasons. Still, coastlines many places even today are subject to periodic inundation from storms, tsunamis, etc. Netherlands has long standing national battle with sea and much valuable experience acquired at great cost. Thanks for contributions so far, gentlemen.

Originally Posted by Lynx_Fox

so what are consequences bad and good?

Higher and unequally distributed raised sea level, loss of arctic habitats and its menagerie of plants of animals or at least their withdrawal to Arctic and Antarctic mountains chains. Short of some unforeseen cause, this would take thousands of years.

Majority of animal species in Antarctica are marine birds like penguins, tough to see them in mountain environment. Weird to even visualize, and Prince has some experience visualizing weirdness...

Ya....that would be the "loss" part.

Originally Posted by Lynx_Fox

Ya....that would be the "loss" part.

But penguins do live in more moderate climates as well, do they not? Unfortunately must wait to read your reply, esteemed moderator, be well.

Not sure what's confusing for you. I laid out two possibilities....loss (as in death) or retreat to high latitude mountains. You seem to want to argue against one or the other for no apparent reason. What was unclear? Or are you: Quibbling? Not enough coffee? Something else? (shrugs).

Penguins DO live in places other than the Antarctic, certain South Atlantic islands, if Prince recalls correctly. Did you mean to imply that the continent would be inundated? This seems unlikely- in fact it may well become a more salubrious place for life of many different kinds. Simple observation of a given volume of water vs an equal volume of ice will reveal which contains more and various living things.

Furthermore, with modern technology, is extinction "forever" if we wish it not to be so?

Will start new thread accordingly.

there's even penguins in the Galapagos - however, during El Nino years the Humboldt current doesn't reach as far north as usual, which leads to starving penguins
so in a warming world i can see how penguins could be squeezed out of much of their current geographical distribution

True, and rising sea levels would in fact inundate some islands, however, ice free Antarctica would still have many beaches and perhaps a more salubrious climate, given that penguins, whose economic value is nil, incidentally, can live in less hostile climates.

Which is better for humanity, a whole continent of untapped mineral resources or a few species of birds? Prince does not miss the passenger pigeon personally, nor yet the dodo. He IS affected by high commodity prices, as are all dotcomrades.

The Galapagos penguins aren't part the discussion of loss in Antarctica because that particular species lives only there.

Originally Posted by Lynx_Fox

The Galapagos penguins aren't part the discussion of loss in Antarctica because that particular species lives only there.

Shame on marnixR for dragging them into it then. Also are no ice caps there, naughty, naughty marnixR!

Prince makes joke.

Anyway, loss of environment is balanced with restoration of more hospitable environment, warmer, probably more abundant food, still dark and relatively cold half of year, no getting around that.

Originally Posted by Lynx_Fox

The Galapagos penguins aren't part the discussion of loss in Antarctica because that particular species lives only there.

it is, however, relevant to see the effect of environmental changes on penguins when their food supply is affected - surely the abundance of food around Antarctica would be affected if that continent became free of ice

Originally Posted by The Finger Prince

Prince makes joke.

I was you that got me going though, because you stated " Penguins DO live in places other than the Antarctic, certain South Atlantic islands, if Prince recalls correctly." as if there were only one species of Penguins, instead of they being an entire group of specialized birds.

Also warmer isn't "more hospitable environment" to species adapted to the cold. Warmer can be less hospitable.

Re penguins.

Here in New Zealand, we have more native species of penguin than the whole of Antarctica. So penguins as a whole will not disappear.

As to harm, it depends on your view point. There is harm to humanity and/or harm to the natural environment. In the long term, with time for evolution, we would end up with more biodiversity than before, since we already know that warm environments spawn more species than cold. In the short term, some biodiversity loss would be inevitable.

Harm to humans?
One of the things much debated by climatologists is weather variation. The suggestion is that weather extremes, like cold and heat snaps will become more common. On the other hand, the view regarding hurricanes is changing, with climatologists now seeing an increase in hurricanes as unlikely. Temperate to arctic storms will become fewer and less damaging, since they are driven by thermal gradients, and the greater warming of higher latitudes leads to reduced thermal gradients.

Some areas will become wetter, and some will become drier. Droughts and floods are both supposed to become more common. With arctic tundra becoming habitable, but some tropical regions becoming desert, it is suggested that climate refugees will become a major problem, and the need to move to better regions has been suggested as a possible cause of war.

My own feeling is that this will be countered by increasing prosperity. If people living in arid areas can trade for food, there will be less need to invade someone else's territory.

In the end , only time will tell.

Hooray for penguins everywhere and enough already.

If ice melted seawater would be more diluted making it theoretically less energy intensive to desalinate to the point of agricultural benefit, or does Prince mistake himself yet again?

Not by enough to really matter.


Do the math--this is a simple one.

Originally Posted by The Finger Prince

Hooray for penguins everywhere and enough already.

If ice melted seawater would be more diluted making it theoretically less energy intensive to desalinate to the point of agricultural benefit, or does Prince mistake himself yet again?

You must be joking. Desal is a terribly expensive way to get water just to supply cities with drinking water. Agriculture needs orders of magnitude more water.

If we were that desperate for water we'd be spending all our money on dams and/or pipelines because that much drought implies a lot of flooding elsewhere. (In case you didn't know, for every degree C it warms - and causes regional droughts - we expect 6% more water vapour in the air, so more regions flooding from downpours. We're already up to 4% more water vapour.)

Originally Posted by adelady

Originally Posted by The Finger Prince

Hooray for penguins everywhere and enough already.

If ice melted seawater would be more diluted making it theoretically less energy intensive to desalinate to the point of agricultural benefit, or does Prince mistake himself yet again?

You must be joking. Desal is a terribly expensive way to get water just to supply cities with drinking water. Agriculture needs orders of magnitude more water.

If we were that desperate for water we'd be spending all our money on dams and/or pipelines because that much drought implies a lot of flooding elsewhere. (In case you didn't know, for every degree C it warms - and causes regional droughts - we expect 6% more water vapour in the air, so more regions flooding from downpours. We're already up to 4% more water vapour.)

This is why more dilute seawater is of benefit, dear lady. So regional droughts provide their own remedy, downpours. Is this a problem? And if so, how is it related to icecaps melting?

"This is why more dilute seawater is of benefit, dear lady. So regional droughts provide their own remedy, downpours. Is this a problem? And if so, how is it related to icecaps melting?" " "

If you look at East Africa and Bangkok, you might notice that the droughts and the floods are in regions poorly placed to be each other's remedy. Just as Texas and Oklahoma's horrible drought were not in the least alleviated by the floods further north and east.

The relationship to icecaps melting is simply the underlying cause of all of these things. It's getting warmer. It melts ice. It makes hot or dry regions hotter or drier. It makes monsoons more dangerous. It melts snow faster so more rivers flood in spring .

My own view of the possible dilution of seawater? If anyone wants to advance the notion that the earth has a natural balance (magical thinking in my view), then this is one possible mechanism. More acidification can be countered by more melting to get pH a bit better balanced. More uneven geographical distribution of freshwater on land countered by marginal dilution of brine in the sea.

All much along the line of criticising statistics - that with your head in the fridge and your feet in the oven, you are definitely not more comfortable 'on average'.

Prince strives always to keep a cool head but is compelled to agree with you. It is getting warmer, better this than cooler. Events will be as they will be and with modern technology we are better equipped to ride them out than we would be otherwise. Fortunately storms and other meteorological events are not getting worse as predicted.

http://www.csccc.info/reports/report_23.pdf

So regional droughts provide their own remedy, downpours.

A flood over dessicated crops doesn't remedy anything.

Or dessicated earth.

I've said it before, looks like I must say it again.

If it were to ever get warm enough to melt all the ice, we will likely be dead long before that.

Really now. To use the ice melting threat and 70-80 meter rise...

Just how much warmer would the earth need to be for that to happen?

The polar caps don't really get a lot of direct sunlight anyway, do they? So, between that and the likely lack of top soil, all that new land would be next to useless for growing food. The land we lost wouldn't be useless, though.

Originally Posted by Wild Cobra

I've said it before, looks like I must say it again.

If it were to ever get warm enough to melt all the ice, we will likely be dead long before that.

Really now. To use the ice melting threat and 70-80 meter rise...

Just how much warmer would the earth need to be for that to happen?

It would have to be a lot hotter, probably 20C or more to counter the geological reasons it got colder during the early Eocene, and remains so--namely a large land mass for snow to form onto on the South pole and isolation by the Antarctic ocean. It would take probably over a thousand years. Even worse case being we burn all the coal, petro, and gas--we'd be a long ways from that point. Not sure about methane hydrates.

Originally Posted by Wild Cobra

I've said it before, looks like I must say it again.

If it were to ever get warm enough to melt all the ice, we will likely be dead long before that.

Really now. To use the ice melting threat and 70-80 meter rise...

Just how much warmer would the earth need to be for that to happen?

Well, history from the last major glaciation tells us that the difference between New York now and New York under 2 miles of ice is about 5 degrees centigrade.

New York above sea level and New York below sea level? No numbers. But if we don't get our act together we will find out - or our grandchildren's grandchildren will.

Originally Posted by Lynx_Fox

Originally Posted by Wild Cobra

I've said it before, looks like I must say it again.

If it were to ever get warm enough to melt all the ice, we will likely be dead long before that.

Really now. To use the ice melting threat and 70-80 meter rise...

Just how much warmer would the earth need to be for that to happen?

It would have to be a lot hotter, probably 20C or more to counter the geological reasons it got colder during the early Eocene, and remains so--namely a large land mass for snow to form onto on the South pole and isolation by the Antarctic ocean. It would take probably over a thousand years. Even worse case being we burn all the coal, petro, and gas--we'd be a long ways from that point. Not sure about methane hydrates.

Well, there's no reason to link sea level rise and "all the ice" melting.

All you need for large (and probably sudden) sea level rise is for land based ice to slide into the sea. That needs only melting, or at least weakening, shorefast sea ice or grounded floating shelves that slow down the movement of glaciers, and enough melting of glaciers themselves to allow faster movement downwards.

And then you get sea level rise from displacement of water when much more than the routine calving of glaciers drops into the ocean, rather than warming to melt that ice or expand existing liquid water. Expansion is the reason for observed sea level rise so far.

Originally Posted by Lynx_Fox

Not by enough to really matter.


Do the math--this is a simple one.

Perhaps so, yet might this have adverse effect, or even salubrious effect upon thermohaline circulation? Probably a matter of where meltwater is concentrated, and there is also local effect freshwater being less dense than salt, degree of admixture due to rate of melting, action of storms, etc. Thank you for comment.

Originally Posted by adelady

Originally Posted by Lynx_Fox

Originally Posted by Wild Cobra

I've said it before, looks like I must say it again.

If it were to ever get warm enough to melt all the ice, we will likely be dead long before that.

Really now. To use the ice melting threat and 70-80 meter rise...

Just how much warmer would the earth need to be for that to happen?

It would have to be a lot hotter, probably 20C or more to counter the geological reasons it got colder during the early Eocene, and remains so--namely a large land mass for snow to form onto on the South pole and isolation by the Antarctic ocean. It would take probably over a thousand years. Even worse case being we burn all the coal, petro, and gas--we'd be a long ways from that point. Not sure about methane hydrates.

Well, there's no reason to link sea level rise and "all the ice" melting.

All you need for large (and probably sudden) sea level rise is for land based ice to slide into the sea. That needs only melting, or at least weakening, shorefast sea ice or grounded floating shelves that slow down the movement of glaciers, and enough melting of glaciers themselves to allow faster movement downwards.

And then you get sea level rise from displacement of water when much more than the routine calving of glaciers drops into the ocean, rather than warming to melt that ice or expand existing liquid water. Expansion is the reason for observed sea level rise so far.

Excellent observations. An increase in volcanic activity could conceivably have such an effect.

http://www.bbc.co.uk/news/world-europe-15995845

And it is established geological fact that poles have been ice-free before, when was the last time?

Look it up since nobody seems inclined to believe Prince.

The last time they were ice free it was due to completely different continent and current placements more than anything else.

Originally Posted by adelady

"This is why more dilute seawater is of benefit, dear lady. So regional droughts provide their own remedy, downpours. Is this a problem? And if so, how is it related to icecaps melting?" " "

If you look at East Africa and Bangkok, you might notice that the droughts and the floods are in regions poorly placed to be each other's remedy. Just as Texas and Oklahoma's horrible drought were not in the least alleviated by the floods further north and east.

The relationship to icecaps melting is simply the underlying cause of all of these things. It's getting warmer. It melts ice. It makes hot or dry regions hotter or drier. It makes monsoons more dangerous. It melts snow faster so more rivers flood in spring .

My own view of the possible dilution of seawater? If anyone wants to advance the notion that the earth has a natural balance (magical thinking in my view), then this is one possible mechanism. More acidification can be countered by more melting to get pH a bit better balanced. More uneven geographical distribution of freshwater on land countered by marginal dilution of brine in the sea.

All much along the line of criticising statistics - that with your head in the fridge and your feet in the oven, you are definitely not more comfortable 'on average'.

As for acidification, this too is potentially a self-correcting situation, as warm water holds less CO2 in solution. Therefore less carbonic acid. If one accepts the so-called "Gaia hypothesis" of Lovelock, the biosphere is indeed comparable to a self-regulating organism with power to maintain homeostasis by means of assorted feedback mechanisms. Prince reserves judgement on this issue.

James Lovelock - Wikipedia, the free encyclopedia

Originally Posted by Lynx_Fox

So regional droughts provide their own remedy, downpours.

A flood over dessicated crops doesn't remedy anything.

Yes, but it is easier to irrigate parched fields than to grow crops in ice or permafrost as well.

Originally Posted by kojax

The polar caps don't really get a lot of direct sunlight anyway, do they? So, between that and the likely lack of top soil, all that new land would be next to useless for growing food. The land we lost wouldn't be useless, though.

You might be surprised, Prince has eaten tasty blueberries off of tundra, growing wild as they must have when first persons crossed from Siberia. Poles receive abundant sunlight in season, is matter of picking or adapting suitable crops.

Originally Posted by The Finger Prince

Originally Posted by adelady

"This is why more dilute seawater is of benefit, dear lady. So regional droughts provide their own remedy, downpours. Is this a problem? And if so, how is it related to icecaps melting?" " "

If you look at East Africa and Bangkok, you might notice that the droughts and the floods are in regions poorly placed to be each other's remedy. Just as Texas and Oklahoma's horrible drought were not in the least alleviated by the floods further north and east.

The relationship to icecaps melting is simply the underlying cause of all of these things. It's getting warmer. It melts ice. It makes hot or dry regions hotter or drier. It makes monsoons more dangerous. It melts snow faster so more rivers flood in spring .

My own view of the possible dilution of seawater? If anyone wants to advance the notion that the earth has a natural balance (magical thinking in my view), then this is one possible mechanism. More acidification can be countered by more melting to get pH a bit better balanced. More uneven geographical distribution of freshwater on land countered by marginal dilution of brine in the sea.

All much along the line of criticising statistics - that with your head in the fridge and your feet in the oven, you are definitely not more comfortable 'on average'.

As for acidification, this too is potentially a self-correcting situation, as warm water holds less CO2 in solution. Therefore less carbonic acid. If one accepts the so-called "Gaia hypothesis" of Lovelock, the biosphere is indeed comparable to a self-regulating organism with power to maintain homeostasis by means of assorted feedback mechanisms. Prince reserves judgement on this issue.

James Lovelock - Wikipedia, the free encyclopedia

Most of the ocean's volume will remain about about 4C regardless of climate. In addition to temperature, Co2 saturation at any particular temperature is also dependent on atmospheric Co2 tension. Within the narrow range of expected changes even above the thermalcline, the pressure of atmospheric co2 will be the dominant term. If the atmosphere was entirely co2, the ocean's ph would be about 4. At pre-industrial Co2 level the Ph was about 8.2--it's now about 8.1. At doubled Co2 from pre-industrial levels it will be about Ph 7.8 or so.

Should I split this discussion of early 20th century chemistry research about co2 and ocean water ph levels...or can we stay on one topic within a thread for a change?

OK, back on topic.

"...poles have been ice-free before, when was the last time?"

Doesn't matter for us. How many billions of primates needing food, water and shelter were around when that happened?

Originally Posted by adelady

OK, back on topic.

"...poles have been ice-free before, when was the last time?"

Doesn't matter for us. How many billions of primates needing food, water and shelter were around when that happened?

The ABC news special "earth 2100" presents a far more grim pictiure of conditions after the melting of the ice caps than anything mentioned here. Weather scientists are mostly in agreement that it is irreversable because as melting ice exposes land it absorbs more sunlight and increases the warming. So probably in most of our own lifetimes we will see dramatic changes.

During the Cretaceous, forests grew in Antarctica, and dinosaurs roamed through those forests. We know from fossils collected. Yet paleoclimatologists have shown that, even back then, winter in Antarctica would have involved months with no sun. It must still have been cold, but not as cold as the present. Average global temperatures were about 6 C more than the present. I assume that meant that high latitude temperatures, such as Antarctica or Greenland, were up to 20 C warmer than what we see today?

I sometimes wonder if this means a form of negative feed-back on world climate to counter the warming. If forests can grow in high latitudes, then a lot more CO2 will be absorbed, leading to a cooling influence?

Originally Posted by ecopoet

The ABC news special "earth 2100" presents a far more grim pictiure of conditions after the melting of the ice caps than anything mentioned here.

Just in sticking to NARROW topic of "melting poles," in what way? I watched the last 15 minute chunk and it seems stupidly alarmist. A bit about Manhattan skyline being flooded and abandoned, when in reality no one expects those Skyscrapers to last the next 90 years, and being among the richest parts of the world, would have many strategies to dike, dam, pump or completely rebuild if they had to. By 2100 the high end of what considered most likely estimates is about 2 meters of sea level rise, the middle estimate is about 1.5 meters (the IPCC IV estimate of +0.9 m is now considered too low)...3 meters if you take the most extreme cases. Something like 2/3 of that rise will be by thermal expansion, the rest from melting ice. Don't take a long term lease on land in Southern Florida.

Originally Posted by Lynx_Fox

Originally Posted by ecopoet

The ABC news special "earth 2100" presents a far more grim pictiure of conditions after the melting of the ice caps than anything mentioned here.

Just in sticking to NARROW topic of "melting poles," in what way? I watched the last 15 minute chunk and it seems stupidly alarmist. A bit about Manhattan skyline being flooded and abandoned, when in reality no one expects those Skyscrapers to last the next 90 years, and being among the richest parts of the world, would have many strategies to dike, dam, pump or completely rebuild if they had to. By 2100 the high end of what considered most likely estimates is about 2 meters of sea level rise, the middle estimate is about 1.5 meters (the IPCC IV estimate of +0.9 m is now considered too low)...3 meters if you take the most extreme cases. Something like 2/3 of that rise will be by thermal expansion, the rest from melting ice. Don't take a long term lease on land in Southern Florida.

Your lack of concern is shared by the great majority of human beings and by most of those in positions of influence, so apparently the human population will go right on growing and expanding its economy and dumping its pollution beyond the limits of the biosphere, at which time Nature will solve the problem in the dramatic ways for which it is so famous, and we humans will be unlucky is any of us survive. I'm unsubscribing from Science Forum

What lack of concern? I asked about what effect in that film relating to melting concerned you. Are you refuting that the skyscrapers probably won't last 100 years? Are you refuting that Manhattan won't have the money to protect itself?

I'm unsubscribing from Science Forum

Sorry to hear that.

Originally Posted by Lynx_Fox

What lack of concern? I asked about what effect in that film relating to melting concerned you. Are you refuting that the skyscrapers probably won't last 100 years? Are you refuting that Manhattan won't have the money to protect itself?

I'm unsubscribing from Science Forum

Sorry to hear that.

So far Science Forum has not noticed my request to unsubscribe.

You appear to have no concept of the Earth as a living biosphere that reacts like all living things to go on existing. That doesn't require a brain, but is ingrained in our living cells that orders our brain to instantly impel the body to run away from danger or to confront and destroy it. So the Earth without a brain, reacts to our massive and growing pollution the only way it can with more violent storms and floods and longer droughts, struggling to return to its naturally evolving balance. There is no intervening limit to that increasing violence beyond the Earth itself, which means we humans could be swept away in a series of mega hurricanes and tornados, or starve to death from extended drought. It has happened before in recorded and unrecorded history and it can and will happen again to us today and tomorrow regardless of our modern technology. But I despair of any hope enough people can understand this in time to safely recycle all our human-generated waste products, and peacefully reduce our human population with family planning education. Our fate appears to be sealed by our human instinct to grow forever.

Originally Posted by ecopoet

You appear to have no concept of the Earth as a living biosphere that reacts like all living things to go on existing.

You are pushing the extreme and non scientific version of the Gaea hypothesis. This is woo. Even the more basic version is unproven, and probably only partially correct.

This is the science forum, and correct science is important to us. Unlike Lynx Fox, I have no problem with you unsubscribing. I get tired of arguing with people who do not understand or follow real science.

Originally Posted by skeptic

Originally Posted by ecopoet

You appear to have no concept of the Earth as a living biosphere that reacts like all living things to go on existing.

You are pushing the extreme and non scientific version of the Gaea hypothesis. This is woo. Even the more basic version is unproven, and probably only partially correct.

This is the science forum, and correct science is important to us. Unlike Lynx Fox, I have no problem with you unsubscribing. I get tired of arguing with people who do not understand or follow real science.

My hope is they all take really good care of themselves and live to see all or most of the dramatic events their polluted economy is precipitating.

The Gaea hypothesis is useful, much like idea of the "selfish gene", if careful applied around empirical science with limitations. Literal definitions badly distort its use and promote them to pseudoscience or even worse--almost a pseudo religious icons. This case is a clear example. We have references to Gaea connected with a film that uses unrealistic events to foster fear. To make it worse, it's unwitting film writer, should have known better. Manhattan flooding is about the worst example I can imagine--it been one of the richest parts of the US for nearly 300 years, and of the world for at least a 100 years. It's got the money to do almost unlimited amount of engineering to make sure the sea-level rise doesn't effect it. Aren't they aware of the sharp criticism that Vice President Gore received for using almost the same example? I guess they don't learn. Sea-level rise of 2 meters will be an enormous problem but only in places where it can't be defended against due to geography or cost. Hundreds of square mile of Southern Florida will be part of the sea scape--Perhaps looking like a network of bridges connecting pockets of walled cities surrounded by shallow sea. Southern Louisiana coastline will recede by many miles--but probably without preserving the dozens of fishing towns. Bangladesh will shrink by a large percent, the wholesale displacement of it's peoples--usually displacement is messy. Almost every port in the world will be need to be rebuilt or abandoned along with the water system for it's people.

I am a strong environmental advocate with a rather bleak view of the future--but I think fear tactics that dream up unlikely scenarios only hurt the case for change. There's plenty of realistic possible and scary events in the future to drum up the needed emotional response without resorting to pseudoscience.
--
Ecopoet I suggest you start a separate thread if you want a broader "earth as a system" discussion.

Originally Posted by Lynx_Fox

The Gaea hypothesis is useful, much like idea of the "selfish gene", if careful applied around empirical science with limitations. Literal definitions badly distort its use and promote them to pseudoscience or even worse--almost a pseudo religious icons. This case is a clear example. We have references to Gaea connected with a film that uses unrealistic events to foster fear. To make it worse, it's unwitting film writer, should have known better. Manhattan flooding is about the worst example I can imagine--it been one of the richest parts of the US for nearly 300 years, and of the world for at least a 100 years. It's got the money to do almost unlimited amount of engineering to make sure the sea-level rise doesn't effect it. Aren't they aware of the sharp criticism that Vice President Gore received for using almost the same example? I guess they don't learn. Sea-level rise of 2 meters will be an enormous problem but only in places where it can't be defended against due to geography or cost. Hundreds of square mile of Southern Florida will be part of the sea scape--Perhaps looking like a network of bridges connecting pockets of walled cities surrounded by shallow sea. Southern Louisiana coastline will recede by many miles--but probably without preserving the dozens of fishing towns. Bangladesh will shrink by a large percent, the wholesale displacement of it's peoples--usually displacement is messy. Almost every port in the world will be need to be rebuilt or abandoned along with the water system for it's people.

I am a strong environmental advocate with a rather bleak view of the future--but I think fear tactics that dream up unlikely scenarios only hurt the case for change. There's plenty of realistic possible and scary events in the future to drum up the needed emotional response without resorting to pseudoscience.
--
Ecopoet I suggest you start a separate thread if you want a broader "earth as a system" discussion.

Now that I understand the weather scientists have calculated the ice cap melting to be "irreversible" I see all such consequences are equally irreversible, especially since it is obvious corporate-dominated humanity has no intention of safely recycling its waste products or peacefully reducing the human population. So, Nature will soon prove itself to be a living system without any more persuasive posting from me. I do hope all the mechanistic thinkers take very good care of themselves so they don't miss the dramatic events.

Originally Posted by ecopoet

--

Now that I understand the weather scientists have calculated the ice cap melting to be "irreversible" I see all such consequences are equally irreversible, ... So, Nature will soon prove itself to be a living system without any more persuasive posting from me. I do hope all the mechanistic thinkers take very good care of themselves so they don't miss the dramatic events.

Irreversible? Only if we fail to think carefully.

And that failure includes the propensity to view 'the planet' as a living entity. It's much more accurate to look at it as a geological / astronomical entity - with the amazing capacity to support life. And not just any life. Mammalian life including us. The Goldilocks place in the universe, just right for life generally and for agriculture sufficient to support a large population of one particular organism specifically. The biological and ecological processes are inexorably linked to the geology and astronomical features of this planet. But we should always be aware that they are a mere fraction of the planet's fundamental structure. (If you want an analogy, think of eyes, ears or nose on a human body. Their correct function is intimately linked with the whole structure, but we can do without one or more of them if we had to. And the planet can do without trees or fish or people if that happens.)

If we're looking at 'reversing' what we've done, we have to stop talking quite so much about forests and the like. That 'carbon cycle' is not the problem - though making things worse than they already are is a bad idea. We've disrupted the multi-million year geologic and atmospheric processes of the planet. We can fix it. There are options. But I don't think speeding up tectonic plate movement to push the Himalayas and its rocks higher, further, faster to speed up weathering processes is one of them.

We'll have to do something that's probably as crude and clumsy as the processes we've used to dig, blast and burn fossils out of their rightful time and place in geological cycles. If we can blast huge holes in the ground or remove mountain tops to get at fossils, we can do the same thing to expose the maximum possible surfaces of rocks that would otherwise take millions of years to extract CO2 from the air and ocean by natural weathering processes. We've accelerated one side of the geological sequester/release equation. We'll have to do something about the other side as well. Eventually.

It won't be pretty. But what our grandchildren's grandchildren are facing is fairly unappealing in the first place.

adelady

I hate to say it, but that is a panic response. We are not at that stage yet. The best response is careful changes and with good management. We need to stop mining coal, and stop deforestation, plus a bunch of other more minor adjustments. Major planetary engineering projects are last resort only, and we are a long way short of that.

Originally Posted by skeptic

adelady

I hate to say it, but that is a panic response. We are not at that stage yet. The best response is careful changes and with good management. We need to stop mining coal, and stop deforestation, plus a bunch of other more minor adjustments. Major planetary engineering projects are last resort only, and we are a long way short of that.

I know that. But I'm afraid the time for careful changes and good management of emissions reduction was 30 years ago. We need to go to zero emissions far, far faster than seems possible in the next 5 or 10 years. And if it ever comes time to 'panic' then that will be far too late.

We're already involved in a major reengineering of the atmosphere and the oceans. One day, people are going to realise that annually knocking off 93 million years' worth of carbon sequestration (in oil alone) needs something a bit more substantial and equally un-gradual to counteract the consequences. Just not doing it any more won't cut the mustard, we have to do something about the damage we've already done that has longer term, accelerating impacts. (Think ocean acidification, sea level rise, coral reef collapse.)

When it comes to careful and gradual implementation, I think something needs to get started on geological reparation. Far more sensible to do some advanced weathering that actually has an effect on ocean acidification as well as atmospheric temperatures. Start sequestration smallish and steadily expand (or rapidly if circumstances change). Don't wait until it's obvious we should have started decades before.

A bit like we should have done with emissions.

Originally Posted by adelady

Originally Posted by ecopoet

--

Now that I understand the weather scientists have calculated the ice cap melting to be "irreversible" I see all such consequences are equally irreversible, ... So, Nature will soon prove itself to be a living system without any more persuasive posting from me. I do hope all the mechanistic thinkers take very good care of themselves so they don't miss the dramatic events.

Irreversible? Only if we fail to think carefully.

And that failure includes the propensity to view 'the planet' as a living entity. It's much more accurate to look at it as a geological / astronomical entity - with the amazing capacity to support life. And not just any life. Mammalian life including us. The Goldilocks place in the universe, just right for life generally and for agriculture sufficient to support a large population of one particular organism specifically. The biological and ecological processes are inexorably linked to the geology and astronomical features of this planet. But we should always be aware that they are a mere fraction of the planet's fundamental structure. (If you want an analogy, think of eyes, ears or nose on a human body. Their correct function is intimately linked with the whole structure, but we can do without one or more of them if we had to. And the planet can do without trees or fish or people if that happens.)

If we're looking at 'reversing' what we've done, we have to stop talking quite so much about forests and the like. That 'carbon cycle' is not the problem - though making things worse than they already are is a bad idea. We've disrupted the multi-million year geologic and atmospheric processes of the planet. We can fix it. There are options. But I don't think speeding up tectonic plate movement to push the Himalayas and its rocks higher, further, faster to speed up weathering processes is one of them.

We'll have to do something that's probably as crude and clumsy as the processes we've used to dig, blast and burn fossils out of their rightful time and place in geological cycles. If we can blast huge holes in the ground or remove mountain tops to get at fossils, we can do the same thing to expose the maximum possible surfaces of rocks that would otherwise take millions of years to extract CO2 from the air and ocean by natural weathering processes. We've accelerated one side of the geological sequester/release equation. We'll have to do something about the other side as well. Eventually.

It won't be pretty. But what our grandchildren's grandchildren are facing is fairly unappealing in the first place.

Three changes could stop global warming and return planet Earth to its natural order:

1. Safely recycle 100% of human-generated waste products.
2. Peacefully reduce the human population with family planning education.
3. Replant and protect the great forests and clean up and protect the global ocean.

But the corporate-dominated governments have no intention of doing anything like that, and the melting ice caps will go on melting as exposed land absorbs sunlight, leading to more weather chaos than our fragile mass society can survive. Stay tuned for dramatic events in the near future.

Originally Posted by ecopoet

[
Three changes could stop global warming and return planet Earth to its natural order:

1. Safely recycle 100% of human-generated waste products.
2. Peacefully reduce the human population with family planning education.
3. Replant and protect the great forests and clean up and protect the global ocean.

But the corporate-dominated governments have no intention of doing anything like that, and the melting ice caps will go on melting as exposed land absorbs sunlight, leading to more weather chaos than our fragile mass society can survive. Stay tuned for dramatic events in the near future.

I'm afraid I don't believe that those three projects could return the planet to "its natural order" in anything like the time required to avoid substantial impacts on sea level rise, agriculture, ocean health. CO2 persists in the atmosphere for centuries
CO2 has a short residence time or Why it's urgent we act now on climate change
and the effects persist for millennia RealClimate: Irreversible Does Not Mean Unstoppable
If greenhouse gas emissions stopped now, Earth would still likely get warmer, new research shows

The planet's 'natural order' is to respond to physical forcings in time-frames well outside puny human perceptions of time. We'd like to see responses to our deliberately thought-out activities (as against our thoughtless destructive careening around) within our own lifetimes or that of one or two further generations. That won't happen. We're going to see things continue to worsen in all sorts of surprising (or not) ways long after we've begun doing the 'right' thing.

What we will need is the mind-set of those European cathedral builders (and their communities) of a few centuries ago. Just keep plugging away at the project even though we know full well we'll never see the final result.

If we really want to 'get back to' the climate regime that has allowed our agriculture and its associated civilisations to flourish, we have to do a lot more than stop our current destructive habits. We need new ones.

Originally Posted by adelady

Originally Posted by ecopoet

[
Three changes could stop global warming and return planet Earth to its natural order:

1. Safely recycle 100% of human-generated waste products.
2. Peacefully reduce the human population with family planning education.
3. Replant and protect the great forests and clean up and protect the global ocean.

But the corporate-dominated governments have no intention of doing anything like that, and the melting ice caps will go on melting as exposed land absorbs sunlight, leading to more weather chaos than our fragile mass society can survive. Stay tuned for dramatic events in the near future.

I'm afraid I don't believe that those three projects could return the planet to "its natural order" in anything like the time required to avoid substantial impacts on sea level rise, agriculture, ocean health. CO2 persists in the atmosphere for centuries
CO2 has a short residence time or Why it's urgent we act now on climate change
and the effects persist for millennia RealClimate: Irreversible Does Not Mean Unstoppable
If greenhouse gas emissions stopped now, Earth would still likely get warmer, new research shows

The planet's 'natural order' is to respond to physical forcings in time-frames well outside puny human perceptions of time. We'd like to see responses to our deliberately thought-out activities (as against our thoughtless destructive careening around) within our own lifetimes or that of one or two further generations. That won't happen. We're going to see things continue to worsen in all sorts of surprising (or not) ways long after we've begun doing the 'right' thing.

What we will need is the mind-set of those European cathedral builders (and their communities) of a few centuries ago. Just keep plugging away at the project even though we know full well we'll never see the final result.

If we really want to 'get back to' the climate regime that has allowed our agriculture and its associated civilisations to flourish, we have to do a lot more than stop our current destructive habits. We need new ones.

I agree. Among those new habits must be 1. Peaceful family planning education to return the human population to a number the biosphere can live with. 2. Safely recycle 100% of all human-generated waste products. 3. Protect the great forests from industrial exploitation, and the global ocean from any human-generated pollution. A smaller human population could then proceed to cautiously use Nature and create a healthy and prosperous lifestyle, no problem. But unfortunately there is a problem. The corporate-dominated governments have no intention of launching any such reforms. Instead, every day they talk about ways to "grow the economy" as though that could go on forever on this planet that is NOT growing to accomodate them. This makes some sort of environmental catastrophe inevitable in our lifetimes as the biosphere reacts to the enormous and growing masses of pollution spewed out into the environment every day. I am so sorry, but all I can do is try to warn everyone, but obviously with very little effect.

Eco,
This is a formal warning and a day off for 1) not staying related to the thread which was about the poles melting and 2) preaching the same thing almost word for word over and over.

You even got invited to start a broader thread.
--

I am so sorry, but all I can do is try to warn everyone, but obviously with very little effect.

You aren't having an effect because you aren't making any kind of scientific arguments.

"I am so sorry, but all I can do is try to warn everyone, but obviously with very little effect."

I know all of that. I know that my soon to be grandchildren will grow up in a world that horrifies me, even terrifies me. But. Those grandchildren are part of a generation that will also have grandchildren. Warning people first, and 'I told you so' second isn't enough.

Telling people they've made a horrible mess is one thing - remember they will have no personal memories of better times - but encouraging them to make the world a better place for their own families, or at least their descendants, is really, really important. Things can be improved. It's just that we've made it more difficult than it should be, and we've made some things impossible .... like preventing a couple of metres of sea level rise.

If we don't give that positive message, we are adding insult to injury.

It's also been demonstrated in some social science experiments that people are much more willing to accept the message of danger and urgency if it's couched in terms that they _can_ do something about it. We can. They can. If we believe we can't, or if we believe we have to wait until people in power decide to do it for us, then we won't get it done. It would be better if governments and corporations behaved better, a few of them already do good things. But we should never let the perfect become the enemy of the good. Support good companies, vote for good politicians - even if 'good' looks like least worst in some cases, do your best in your local community. It will never be enough to prevent some bad things happening, but we can prevent worse things and we can reduce the number and severity of the unavoidable impacts.

But only if we do something about it.

Lynx Fox. Sorry. I should have refreshed before I posted this. Do you want it deleted?

No problem.

I like this point:

remember they will have no personal memories of better times

I reminded me of my dad bringing me to a beach one day to look for lobsters stranded in pools during an extreme low tide along the Maine coast. Off shore on a rock outcropping few hundred feet away from where we explored there was the remains of a poured concrete foundation bent and twisted with rebar sticking out. He explained when he was a boy a house stood there built on a sandy point precariously overlooking the ocean. A winter storm swept away the sand, taking the beach and destroying the house. It was a powerful message only because how dad was telling it to me--and even at that it was rather abstract. I hadn't known the smiling people who owned that summer home, never accepted a refreshing lemon aid from them, never seen the house, never flown a kite off that beach nor known similar experiences that my dad might have known. It's hard to lament the lose of things we didn't experience directly. I think there will be many similar stories to tell over the next few generations.

On the other hand, there is no point getting our knickers in a twist simply about change. The world is changing. The world has always changed. Underwater archaeologists have found the remains of cities on the bottom of the Mediterranean, and off north east India under the Indian Ocean, due to sea level rise over the past 3,000 years. Other archaeologists are dredging for Stone Age settlements under the North Sea.

We cannot stop change, and we should not get paranoid about change. The world is changing, and will continue to. The trend over thousands of years has been for slow sea level rise and loss of coastline. This will continue, and accelerate to a degree. Major human made change is what we need to worry about, and it is sometimes difficult to tell which is human generated, and which is 'natural'.

We know that, by 2100, we can expect 0.5 to 1 metres of sea level rise. That is mostly something humanity can adapt to. With a little proper and targetted development, we can counter warming to the point where sea levels will not rise much more than that. I am optimistic enough to believe that is the likely outcome, since we see so many developments already under way, which will bear fruit some time in the next 50 odd years. Some much sooner.

Originally Posted by skeptic

The main bad consequence is an 80 metres rise in sea level. (Assuming all ice melted, including Antarctica, which is unlikely any time within the next thousand years). This would flood about 5% of all land surfaces, which does not sound much, until you realise that a very large percentage of the world's cities are within that 5%.

It is actually, far more likely that the sea level rise up to the year 2100 will be less than one metre. This will require massive expenditure on sea dykes around major cities on the coast, or inside tidal river systems, but could be done. That level of sea level rise is something humanity can adapt to. 80 metres would be more difficult, but is unlikely any time in the foreseeable future.

It's happening far faster than we think .. science is astounded at how quickly it's happening. 80 metres would get rid of some unsightly cities though. The only thing frightening about all this to most people is that it's happening at home AND abroad .. if it was only happening abroad what the heck difference would it make?

We know that, by 2100, we can expect 0.5 to 1 metres of sea level rise

And plan for about 2m or even a bit more which is what the semi-empirical models are showing according to Vermeer's research.
"For future global temperature scenarios of the Intergovernmental Panel on Climate Change's Fourth Assessment Report, the relationship projects a sea-level rise ranging from 75 to 190 cm for the period 1990–2100. "
Global sea level linked to global temperature

Climate related sea-level variations over the past two millennia

Originally Posted by skeptic

On the other hand, there is no point getting our knickers in a twist simply about change. The world is changing. The world has always changed. Underwater archaeologists have found the remains of cities on the bottom of the Mediterranean, and off north east India under the Indian Ocean, due to sea level rise over the past 3,000 years. Other archaeologists are dredging for Stone Age settlements under the North Sea.

We cannot stop change, and we should not get paranoid about change. The world is changing, and will continue to. The trend over thousands of years has been for slow sea level rise and loss of coastline. This will continue, and accelerate to a degree. Major human made change is what we need to worry about, and it is sometimes difficult to tell which is human generated, and which is 'natural'.

We know that, by 2100, we can expect 0.5 to 1 metres of sea level rise. That is mostly something humanity can adapt to. With a little proper and targetted development, we can counter warming to the point where sea levels will not rise much more than that. I am optimistic enough to believe that is the likely outcome, since we see so many developments already under way, which will bear fruit some time in the next 50 odd years. Some much sooner.

Not exactly. The issue of rising sea levels over the millennia is a mixed message. Britain is a great example of glacial rebound, with the north still gradually rising as a consequence of the release of gravitational pressure from now long-gone ice sheets. This exerts leverage on the southeast which is still subsiding and therefore receding under the sea.

But change is not an issue. Speed of change is a huge issue. And the changes we've introduced to the atmosphere and the oceans over the last couple of centuries are the sort of things that might take anywhere from 10 millennia to 10s of millions of years in the geological record. And that's the pace you need to allow biological evolution to 'keep up' with changed climate or ocean or geological circumstances.

I'd like to agree with you on sea level rise by 2100, but I'm not convinced. Arctic sea ice loss, glacier loss, ocean warming are all happening much, much faster than scientists themselves were expecting even 5 years ago. Decades faster.

I'm more inclined to think that we'll blow right past doubling pre-industrial CO2 concentration and be on our way to the next doubling before serious mitigation begins to have any effect at all. Which means 2 or more metres of sea level rise are more or less inevitable by 2100 ......

But, irreversible does not mean unstoppable. By the time everyone realises that it's really happening, so that rich countries are facing losing their ports and airports and ocean-water-cooled power plants and whole heaps of essential infrastructure (like sewage processing facilities) and it's not just remote poor areas like the Nile delta or Bangladesh disappearing under advancing seas, some serious arm-twisting will start.

Then we'll see some real resources dedicated to mitigation. (I probably won't - I don't expect to live much beyond 2040.) And that will begin to slow the process down.

On sea level rise.
There are numerous predictions for the amount of sea level rise by 2100. If we project current rise, at 2 to 3 mm per year, we will get about 0.25 metres rise. The IPCC predicts 0.5 to 1 metres, which is what I stated. Other 'authorities' predict anything from 0.25 to 5 metres. However, the IPCC would seem to be the most reputable of all those sources, and that is who I quote.

The IPCC data is more than 5 years old. The sources I provided, that up that estimate, are some of the same writing the new report due out next year. That's why I prefer them.

Also in the game of planning for the future, you don't plan for the average estimate--you high side things a bit.

Originally Posted by Lynx_Fox

...you don't plan for the average estimate--you high side things a bit.

true - extremes are more likely to hurt you than the average

The IPCC reports are fantastic. But they have two limitations.

The first is that they absolutely must be the best of what's been done up to a certain time ..... several months before the reports are finalised. So anything that is just showing up and hasn't been confirmed by further work doesn't get more than a mention, if that.

The second and more important limitation is that the final reports have to be signed off by all the participating countries. Which leads to statements of (un)certainty and projections for the immediate and longer-term future being edited by modifying, re-phrasing, adding or excluding context - lots of minor adjustments of tone. Collectively, these changes have always added up to a significant smoothing off or toning down of statements which initially conveyed urgency. It's entirely possible that the next report will find the coúntries' representatives arguing for stronger statements, but experience tells us it's not highly likely. I'd like to see the 'director's cut' of the pre-negotiation drafts as evidence before I accept that one.

I saw one remark about the IPCC consensus. " If you want to know what climate science has done, read the IPCC. If you want to know where it's going, read James Hansen." He is, after all, the one with the strongest and longest record of making 20+ year projections that turn out to be pretty well on the money.

On climate science predictions.

The more extreme predictions use phenomena that may happen, but which has not yet been demonstrated to happen. For example : the release of methane from what is now permafrost. There are reasons to expect this, in theory. But science history is redolent with examples of things expected in theory that did not happen in practise.

So I do not believe James Hansen. When he says that sea levels will rise 5 metres by 2100, my bullsh!t alarm goes off! Much more reasonable to look to the median projections, which are of the order of 0.5 to 1 metre.

The other thing that makes me ponder is climate change history. Global warming is now about 150 years old. The world, in theory, has been warming due to human activity for that period. Yet, in practise, even though we can demonstrate temperature rise and sea level rise, nothing has yet occurred that can be called destructive. Sea levels have risen at 2 to 3 mm per year, but this is insufficient to even be a nuisance. At least so far. Warming has given rise to lots and lots of claims of damage, but none that I am aware of that can be shown scientifically to be correct.

The future may well be a different kettle of fish entirely, but as Niels Bohr said; "Predictions are hard, especially about the future!"

I respect your skepticism, but there's no reason to ignore most probable predictions of sea level raise from more current research than the IPCCs results. The best we can do is go with the best most current estimates we have and that's no longer the IPCC dated report.

There's a growing number of attributions studies that are looking at the effects we've already experienced. You can't ignore them either.

Originally Posted by skeptic

On climate science predictions.

... So I do not believe James Hansen. When he says that sea levels will rise 5 metres by 2100, my bullsh!t alarm goes off! Much more reasonable to look to the median projections, which are of the order of 0.5 to 1 metre.

The other thing that makes me ponder is climate change history. Global warming is now about 150 years old. The world, in theory, has been warming due to human activity for that period. Yet, in practise, even though we can demonstrate temperature rise and sea level rise, nothing has yet occurred that can be called destructive. Sea levels have risen at 2 to 3 mm per year, but this is insufficient to even be a nuisance. At least so far. Warming has given rise to lots and lots of claims of damage, but none that I am aware of that can be shown scientifically to be correct.

The future may well be a different kettle of fish entirely, but as Niels Bohr said; "Predictions are hard, especially about the future!"

I'm not so relaxed. The reason? Because things that weren't expected until mid-century or later are already happening.

The Arctic sea ice is disappearing before our eyes - when even the last IPCC report was projecting the first severe impacts around 2030 and disappearance of late summer ice even later. It's entirely possible that the North Pole might be free of ice in a September occurring within 10 years. September 2011 sea ice volume, looking back and ahead - Arctic Sea Ice

At least Antarctic sea ice is behaving pretty much as modelled. (Minor increases or stability in extent for x years before starting to decline rapidly. Though I expect that this may be complicated by quickening release of land-based ice. We're still in 'x' territory.)

And the impacts of extreme weather events are also increasing a few decades sooner than was commonly expected 5 or 10 years ago.

As for James Hansen's projections of likely sea level rise. Start reading at "d. Holocene versus prior interglacial periods and the Pliocene" on page 12 of http://www.columbia.edu/~jeh1/mailin...kovicPaper.pdf Then think a bit more about it.

Originally Posted by skeptic

On climate science predictions.

The more extreme predictions use phenomena that may happen, but which has not yet been demonstrated to happen. For example : the release of methane from what is now permafrost. There are reasons to expect this, in theory. But science history is redolent with examples of things expected in theory that did not happen in practise.

So I do not believe James Hansen. When he says that sea levels will rise 5 metres by 2100, my bullsh!t alarm goes off! Much more reasonable to look to the median projections, which are of the order of 0.5 to 1 metre.

There are places in the arctic where you can now set the methane aflame with a cigarette lighter. I predict a five metre rise by 2040 latest.

There are places in the arctic where you can now set the methane aflame with a cigarette lighter.

While that is true, the detailed study of those places, how common they are and how much is being out gassed, are relatively recent. Nor have I seen any proxies developed for estimating past levels.

Have you seen anything that we could consider strong evidence that the rate of arctic methane is increasing?

Originally Posted by adelady

As for James Hansen's projections of likely sea level rise. Start reading at "d. Holocene versus prior interglacial periods and the Pliocene" on page 12 of http://www.columbia.edu/~jeh1/mailin...kovicPaper.pdf Then think a bit more about it.

Adelady

Hansen's model of exponential sea level rise, with a ten year doubling time is not accepted by most other climatologists, and there is no empirical evidence to suggest it is true. I cannot see any real reason to suggest such a model, apart from speculation.

As Niels Bohr said : "Prediction is hard. Especially about the future."

Hansen still activates my bullsh!t alarm.

Originally Posted by skeptic

Hansen still activates my bullsh!t alarm.

Did you read all the way to the conclusions? Hansen's working on particular scenarios. Most importantly ...

"BAU scenarios result in global warming of the order of 3-6°C. It is this scenario for which we assert that multi-meter sea level rise on the century time scale are not only possible, but almost dead certain. Such a huge rapidly increasing climate forcing dwarfs anything in the paleoclimate record. Antarctic ice shelves would disappear and the lower reaches of the Antarctic ice sheets would experience summer melt comparable to that on Greenland today. ....."

I think that it behoves all of us to take notice of the person who managed to get climate prediction down so accurately.
This is the conclusion of a review of Hansen's 1988 projection at Hansen's 1988 prediction was wrong .

Had Hansen used a climate model with a climate sensitivity of approximate 3.4°C for 2xCO₂ (at least in the short-term, it's likely larger in the long-term due to slow-acting feedbacks), he would have projected the ensuing rate of global surface temperature change accurately. Not only that, but he projected the spatial distribution of the warming with a high level of accuracy. The take-home message should not be "Hansen was wrong therefore climate models and the anthropogenic global warming theory are wrong;" the correct conclusion is that Hansen's study is another piece of evidence that climate sensitivity is in the IPCC stated range of 2-4.5°C for 2xCO₂.

(Note that he did this using computing power a modern teenager would sneer at. )

He may not be right. But he cannot be breezily dismissed in the way that any of the rest of us can so easily be disregarded.

You need to contest each element of the scenario. Will CO2 concentrations continue to increase? Will that concentration result in GAT increase of 3C to 6C? Will that accelerate loss of ice mass from Greenland and Antarctica? Will that acceleration continue, slow down, reverse or accelerate further? What are the time-scales for each of these?

That's actually an excellent paper to survey various methods, assumptions, uncertainties and modeling efforts towards figuring out sea level change. I hope the IPCC report chapter next year (or is it the following?) does as good as job.

I can 'breezily dismiss' Hansen's ideas as long as they do not coincide with those of most climatologists.

The statement in the reference above that Antarctic ice shelves may disappear is just absurd. Some of those ice shelves are 4 km thick and the air above them averages minus 50 C. It would take a massive warming for them to even begin to melt, and even then it would take hundreds or thousands of years for that thickness of ice to melt. While this time span is nothing geologically, on the human time scale, it is enormous. Long before such melting could even begin to get going, human activity would have totally changed the situation once more.

Originally Posted by skeptic

The statement in the reference above that Antarctic ice shelves may disappear is just absurd. Some of those ice shelves are 4 km thick and the air above them averages minus 50 C. It would take a massive warming for them to even begin to melt, and even then it would take hundreds or thousands of years for that thickness of ice to melt. While this time span is nothing geologically, on the human time scale, it is enormous. Long before such melting could even begin to get going, human activity would have totally changed the situation once more.

This seems a naive interpretation. The actual quote is:

Antarctic ice shelves would disappear and the lower reaches of the Antarctic ice sheets would experience summer melt comparable to that on Greenland today.

It does not say all ice shelves would have to melt in order to disappear. They just have to weaken and break away, partially or completely, in order to destabilize the glaciers they are buttressing. After all, it is the land based ice that will cause sea level rise, not the floating ice. The floating ice is warmed and potentially melted, then weakened, from underneath, by warmer water temperatures, regardless of the air temperature. If the air temperature is also warmer, so much the worse.

I think we might have a nomenclature problem here. When we talk about Antarctic ice shelves, we're talking about ice near the coast that is attached to the land and is grounded on an island or the like. It's pretty thick in places, but nothing like the kms of the land ice. There is sea water beneath.

We're not talking about land ice or the glaciers themselves.

Certainly the land ice is not going to melt any time soon - probably not for several thousand years even by the most pessimistic forecasts.

Originally Posted by skeptic

Certainly the land ice is not going to melt any time soon - probably not for several thousand years even by the most pessimistic forecasts.

I think we've been here before. It doesn't need to melt.

All that is needed for fast sea level rise is for ice shelves or glacier tongues or sea ice (which are already in or on the ocean so they don't affect sea level) to melt or thin or weaken so that they can no longer hold back glaciers as they currently do. When larger chunks of these massive ice sources slide or drop into the ocean, they raise the sea level instantly. They could float, sail or barge around the oceans for decades or centuries without melting. But the sea level rise has already happened.

adelady

That can happen only with the coastal ice sheets. The vast bulk of ice in Antarctica is inland, and the very deep ice masses have depressions under them. They cannot slide, any more than the water in a volcanic crater can flow out. They are contained.

Have the Russians drilled through the last few feet of ice to Lake Vostok yet? I wonder what they found or will find?

That can happen only with the coastal ice sheets.

The Antarctic glaciers that would empty into the sea were they not blocked by shelves are easily large enough to make serious changes in the sea level. The question is how fast they would flow.

Why are we ignoring Greenland? The evidence from Greenland is that when glaciers start sliding like this they tend to move faster than current standard predictions held (which were based on the measured flow rates of more or less stable, long-lived glaciers - not newly released ones lubed by meltwater ). And the glaciers currently beginning to flow from Greenland are significant - especially in that they dump their cold fresh water on top of the Gulf Stream's northern reach, a circumstance that from other causes seems to have been correlated with dramatic and sudden changes in the climate of Europe, in the past.

And the glaciers currently beginning to flow from Greenland are significant - especially in that they dump their cold fresh water on top of the Gulf Stream's northern reach, a circumstance that from other causes seems to have been correlated with dramatic and sudden changes in the climate of Europe, in the past.

Changes in the Gulf Stream are unlikely to have those effects on Europe in the current climate. Massive though the quantities of ice in Greenland and Antarctica may be, they're nothing like the unimaginable size of the Laurentide and associated ice masses which melted at the end of that glaciation. Simply put. There may be enough meltwater to inundate many areas of the world's port cities and river deltas, but it's not enough and certainly not cold enough to put the Gulf Stream out of action.

Originally Posted by adelady

And the glaciers currently beginning to flow from Greenland are significant - especially in that they dump their cold fresh water on top of the Gulf Stream's northern reach, a circumstance that from other causes seems to have been correlated with dramatic and sudden changes in the climate of Europe, in the past.

Changes in the Gulf Stream are unlikely to have those effects on Europe in the current climate. Massive though the quantities of ice in Greenland and Antarctica may be, they're nothing like the unimaginable size of the Laurentide and associated ice masses which melted at the end of that glaciation. Simply put. There may be enough meltwater to inundate many areas of the world's port cities and river deltas, but it's not enough and certainly not cold enough to put the Gulf Stream out of action.

Word from Newfoundland .. icebergs no longer coming far enough south as to draw tourists. That from a Newfoundland member of Canada's Armed Forces. Do the loads of snow in England and Scotland this year not indicate the Gulf Stream is already affected?

Yes, the Greenland glaciers are said to be sliding faster. Not only that, but what about the effects of Icelands under ice volcanoes?
Ther is supposed to be tremendous capacity for sudden melting there.

Originally Posted by adelady

Originally Posted by skeptic

On climate science predictions.

... So I do not believe James Hansen. When he says that sea levels will rise 5 metres by 2100, my bullsh!t alarm goes off! Much more reasonable to look to the median projections, which are of the order of 0.5 to 1 metre.

The other thing that makes me ponder is climate change history. Global warming is now about 150 years old. The world, in theory, has been warming due to human activity for that period. Yet, in practise, even though we can demonstrate temperature rise and sea level rise, nothing has yet occurred that can be called destructive. Sea levels have risen at 2 to 3 mm per year, but this is insufficient to even be a nuisance. At least so far. Warming has given rise to lots and lots of claims of damage, but none that I am aware of that can be shown scientifically to be correct.

The future may well be a different kettle of fish entirely, but as Niels Bohr said; "Predictions are hard, especially about the future!"

I'm not so relaxed. The reason? Because things that weren't expected until mid-century or later are already happening.

The Arctic sea ice is disappearing before our eyes - when even the last IPCC report was projecting the first severe impacts around 2030 and disappearance of late summer ice even later. It's entirely possible that the North Pole might be free of ice in a September occurring within 10 years. September 2011 sea ice volume, looking back and ahead - Arctic Sea Ice

At least Antarctic sea ice is behaving pretty much as modelled. (Minor increases or stability in extent for x years before starting to decline rapidly. Though I expect that this may be complicated by quickening release of land-based ice. We're still in 'x' territory.)

And the impacts of extreme weather events are also increasing a few decades sooner than was commonly expected 5 or 10 years ago.

As for James Hansen's projections of likely sea level rise. Start reading at "d. Holocene versus prior interglacial periods and the Pliocene" on page 12 of http://www.columbia.edu/~jeh1/mailin...kovicPaper.pdf Then think a bit more about it.

Here in Ottawa Canada we have springtime in mid December when we "should" have tons of snow. The warm air masses from the Gulf now come through the Mississippi and Ohio valleys and flow into the Arctic where normal winter cold air masses in the arctic held them to the south. Changes are moving MUCH faster than almost anyone predicted (except for the crazy Hippioes) and any reasonably educated person can see it for themselves with no need of instruments or sattelites.

Originally Posted by ecopoet

Originally Posted by adelady

OK, back on topic.

"...poles have been ice-free before, when was the last time?"

Doesn't matter for us. How many billions of primates needing food, water and shelter were around when that happened?

The ABC news special "earth 2100" presents a far more grim pictiure of conditions after the melting of the ice caps than anything mentioned here. Weather scientists are mostly in agreement that it is irreversable because as melting ice exposes land it absorbs more sunlight and increases the warming. So probably in most of our own lifetimes we will see dramatic changes.

If "irreversible" why do we have ice there today? It was noted in beginning and most informed persons knowing and participating on thread are aware that this has happened before. Prince recommends that you investigate more deeply than television news. Furthermore, some "dramatic changes" have FAILED to materialize so far as projected by IPCC models upon which your yellow alarmist TV journalism is most probably based.

Originally Posted by Aristarchus in Exile

Originally Posted by adelady

And the glaciers currently beginning to flow from Greenland are significant - especially in that they dump their cold fresh water on top of the Gulf Stream's northern reach, a circumstance that from other causes seems to have been correlated with dramatic and sudden changes in the climate of Europe, in the past.

Changes in the Gulf Stream are unlikely to have those effects on Europe in the current climate. Massive though the quantities of ice in Greenland and Antarctica may be, they're nothing like the unimaginable size of the Laurentide and associated ice masses which melted at the end of that glaciation. Simply put. There may be enough meltwater to inundate many areas of the world's port cities and river deltas, but it's not enough and certainly not cold enough to put the Gulf Stream out of action.

Word from Newfoundland .. icebergs no longer coming far enough south as to draw tourists. That from a Newfoundland member of Canada's Armed Forces. Do the loads of snow in England and Scotland this year not indicate the Gulf Stream is already affected?

Yes, the Greenland glaciers are said to be sliding faster. Not only that, but what about the effects of Icelands under ice volcanoes?
Ther is supposed to be tremendous capacity for sudden melting there.

And volcanic activity is caused, of course, like everything else, by excess CO2 emissions. In point of fact, massive volcanic activity would do much to cool down Earth planet as records indicate.

Volcanic Gases and Climate Change Overview

Originally Posted by skeptic

adelady

That can happen only with the coastal ice sheets. The vast bulk of ice in Antarctica is inland, and the very deep ice masses have depressions under them. They cannot slide, any more than the water in a volcanic crater can flow out. They are contained.

As Prince understands, part of reason for such depressions is weight of ice, so melting runoff would decrease this tendency as time progressed. Or is this not so?

Furthermore, some "dramatic changes" have FAILED to materialize so far as projected by IPCC models upon which your yellow alarmist TV journalism is most probably based.

This one often comes up and it flummoxes me. The negative changes I notice are running well ahead of the various IPCC projections.

There are plenty of unhappy, and probably dramatic, events expected as the next 20, 50, 80 years unfold. But I can't for the life of me think of any changes being expected in the last 5 or 10 years that haven't occurred.

Originally Posted by The Finger Prince

If "irreversible" why do we have ice there today? It was noted in beginning and most informed persons knowing and participating on thread are aware that this has happened before. Prince recommends that you investigate more deeply than television news.

Irreversible is an exaggeration, but meant in terms of our lifetimes and or at least in the timeline of decades to centuries. For instance the several hundred square miles of ice shelf we've lost in Canada and Antarctica (e.g. larson B) over the past ten years took thousands of years to build. They aren't coming back anytime in soon and certainly not before 2100.

Furthermore, some "dramatic changes" have FAILED to materialize so far as projected by IPCC models upon which your yellow alarmist TV journalism is most probably based.

Such as? When you show the prediction it would be good to have chapter and section of the IPCC report, since it's publicly available along with the comparison of the scientific study which shows it didn't happen.

(there actually a few cases of this, mostly minor or since explained, and none of which were picked up by the media outlets....but I'm curious which ones you meant)

Irreversible is an exaggeration, but meant in terms of our lifetimes and or at least in the timeline of decades to centuries.

Well, species extinction is irreversible. But I suppose that's not really what we're talking about.

The big issue is that irreversible does not mean unstoppable.

The fact that some changes are truly irreversible does not mean that we can't halt, reverse or ameliorate some of the processes. Sea level rise is the classic case. We cannot reverse the changes we've already instigated - and we don't know exactly how much sea level rise we'll get as a consequence. There will be significant, negative effects. That doesn't mean we should throw up our hands in horror and let it rip.

The unavoidable fact that we're in for some truly devastating consequences should make us even more determined to prevent anything worse.

Originally Posted by Aristarchus in Exile

Word from Newfoundland .. icebergs no longer coming far enough south as to draw tourists. That from a Newfoundland member of Canada's Armed Forces. Do the loads of snow in England and Scotland this year not indicate the Gulf Stream is already affected?
[/QUOTE]

No, not really. The weather in any particular winter is far more affected by atmospheric circulation patterns such as the NAO and AO.

Originally Posted by The Finger Prince

And volcanic activity is caused, of course, like everything else, by excess CO2 emissions.
Volcanic Gases and Climate Change Overview

How the hell did you come up with that connection???

How the hell did you come up with that connection???

Well, let's be honest, there is a connection ....... it just happens to be the wrong way round. 2 relevant facts.

1. The planet would still be in snowball earth mode if there hadn't been a very active volcanic period releasing CO2 to kickstart, and then enhance, enough warming to melt sea ice near the equator. (We would never have been here anyway to notice the difference if that snowball hadn't gone away and allowed life to get going again. No mammalian development = no us.)

2. Human emissions now are 100 times the total of all volcanic emissions - including the undersea volcanoes.

Originally Posted by The Finger Prince

Originally Posted by ecopoet

Originally Posted by adelady

OK, back on topic.

"...poles have been ice-free before, when was the last time?"

Doesn't matter for us. How many billions of primates needing food, water and shelter were around when that happened?

The ABC news special "earth 2100" presents a far more grim pictiure of conditions after the melting of the ice caps than anything mentioned here. Weather scientists are mostly in agreement that it is irreversable because as melting ice exposes land it absorbs more sunlight and increases the warming. So probably in most of our own lifetimes we will see dramatic changes.

If "irreversible" why do we have ice there today? It was noted in beginning and most informed persons knowing and participating on thread are aware that this has happened before. Prince recommends that you investigate more deeply than television news. Furthermore, some "dramatic changes" have FAILED to materialize so far as projected by IPCC models upon which your yellow alarmist TV journalism is most probably based.

They didn't count on the oceans' capability of absorbing a lot of heat quickly, which has just been discovered. That heat will be released through ocean currents coming to the surface. Also, I believe a lot of heat has been transferred to upper atmospheres, but it will circulate down very quickly and unexpectedly.

Originally Posted by Aristarchus in Exile

Also, I believe a lot of heat has been transferred to upper atmospheres, but it will circulate down very quickly and unexpectedly.

Actually, quite the reverse. Depends what you mean by 'upper atmosphere' of course. But the mechanism of action of greenhouse gases involves trapping heat in the lower troposphere, meaning the the atmosphere at higher altitudes is actually measurably cooler. This cooling of the higher atmosphere is one of the signs that greenhouse gas warming is the machanism for global increase in temperature.

Originally Posted by adelady

Changes in the Gulf Stream are unlikely to have those effects on Europe in the current climate. Massive though the quantities of ice in Greenland and Antarctica may be, they're nothing like the unimaginable size of the Laurentide and associated ice masses which melted at the end of that glaciation. Simply put. There may be enough meltwater to inundate many areas of the world's port cities and river deltas, but it's not enough and certainly not cold enough to put the Gulf Stream out of action.

The last time the Gulf Stream was altered, with large effects on the climate, it did not take nearly as much cold fresh water as you seem to be claiming was involved. The entire Laurentide and related ice masses were not involved - current theory is that a quick release of some meltwater piled up in Hudson Bay or someplace was all it took.

A dramatic but not impossible speedup of the Greenland glacial flow would do as much. There's enough water there.

The Gulf Stream is not "put out of action", but merely capped or covered in its northern reach with a few meters of colder but lighter (fresh) water - changing its course somewhat, and sealing its warmth from the overlying air.

Originally Posted by iceaura

Originally Posted by adelady

Changes in the Gulf Stream are unlikely to have those effects on Europe in the current climate. Massive though the quantities of ice in Greenland and Antarctica may be, they're nothing like the unimaginable size of the Laurentide and associated ice masses which melted at the end of that glaciation. Simply put. There may be enough meltwater to inundate many areas of the world's port cities and river deltas, but it's not enough and certainly not cold enough to put the Gulf Stream out of action.

The last time the Gulf Stream was altered, with large effects on the climate, it did not take nearly as much cold fresh water as you seem to be claiming was involved. The entire Laurentide and related ice masses were not involved - current theory is that a quick release of some meltwater piled up in Hudson Bay or someplace was all it took.

Do you have a link?
Or could you just be misinterpreting the several papers over the past few years that link the deglaciation of the Leurentide ice sheet into Lake Agassiz, which took three prominent routes to the ocean---through the Mckenzie river, down what is today the Mississippi or through Hudson bay. There's also several papers that suggest the Eastern drainage into today's Saint Lawrence Seaway are well timed with the Younger Dryas event which could have slowed or stopped the gulf stream (usually associated with the Atlantic meridional overturning circulation which is much larger). (discussed here: Geochemical proxies of North American freshwater routing during the Younger Dryas cold event)

Other than an impact hypothesis that are pretty much ruled out in this study What Caused the Younger Dryas Cold Event?, just about all the major shut downs are associated with deicing from the Leurentide. Greenland cant come anywhere close in magnitude to that amount of fresh water.

http://www.nature.com/nature/journal...ture08954.html

Originally Posted by skeptic

Originally Posted by Aristarchus in Exile

Also, I believe a lot of heat has been transferred to upper atmospheres, but it will circulate down very quickly and unexpectedly.

Actually, quite the reverse. Depends what you mean by 'upper atmosphere' of course. But the mechanism of action of greenhouse gases involves trapping heat in the lower troposphere, meaning the the atmosphere at higher altitudes is actually measurably cooler. This cooling of the higher atmosphere is one of the signs that greenhouse gas warming is the machanism for global increase in temperature.

Not being an expert I would say the upper trophosphere. Has anyone measured the jet streams for temperature changes?

Originally Posted by lynx

Other than an impact hypothesis that are pretty much ruled out in this study What Caused the Younger Dryas Cold Event?, just about all the major shut downs are associated with deicing from the Leurentide. Greenland cant come anywhere close in magnitude to that amount of fresh water.

The deicing from the Laurentide did not happen all at once - none of those events involved the whole huge mass of the Laurentide glaciation. They were all events along the way, involving comparatively small melt jambs and the like that happened to release into the right part of the ocean - and Greenland is in the right part of the ocean, with considerable ice now melting rapidly.

And we are not talking about "shutdown" as such - overlayment or small deflection would be enough.

Originally Posted by iceaura

And we are not talking about "shutdown" as such - overlayment or small deflection would be enough.

You don't seem to understand the share volume of ice and melt water involved.
"Melting of the Laurentide Ice Sheet during the last deglaciation added large volumes of water to many rivers and lakes of North America and to the world's oceans. The volume and routing of this meltwater not only helped shape the land's surface but also played a role in the evolution of late-glacial climate. A computerized model was prepared to quantify meltwater generation from seven drainage areas along the southern side of the Laurentide Ice Sheet at 500-yr time slices between 14,000 and 8000 yr B.P. Nearly all waters reaching the oceans flowed through the St. Lawrence, Hudson, or Mississippi River valleys. Discharge through the Mississippi River to the Gulf of Mexico during late-glacial time varied by more than a factor of 5, ranging between 17,400 m³ sec⁻¹ (550 km³ yr⁻¹) and 98,200 m³ sec⁻¹ (3200 km³ yr⁻¹). Discharge entering the North Atlantic Ocean through the St. Lawrence and Hudson valleys ranged between 20,300 m³ sec⁻¹ (640 km³ yr⁻¹) and 65,300 m³ sec⁻¹ (2060 km³ yr⁻¹), with very abrupt, twofold changes at about 11,000, 10,000, and 9500 yr B.P. as a result of the rerouting of water from the Lake Agassiz basin. As the areal extent and mass of the Laurentide Ice Sheet diminished, the total volume of meltwater plus runoff due to precipitation from its southern side declined from 3800 km³ yr⁻¹ at about 14,000 yr B.P. to 2100 to 2600 km³ yr⁻¹ between 11,500 and 8000 yr B.P. No meltwater entered the Gulf of Mexico after 9500 yr B.P. After the demise of the ice sheet over Hudson Bay about 8000 yr B.P., the modern continental drainage network was established and flows through the St. Lawrence declined to modern values of about 320 km³ yr^−1"

http://www.sciencedirect.com/science/article/pii/003358949090069W

Lake Agassiz was much larger than all the combined lakes of the world are today. Those flow rates into the outlets, that lasted centuries, are 10-15 times what the Amazon river puts out today and almost ten times the current estimated melting rate of all of Greenland. Geologist are starting to see very similar patterns in prior short glacial period as the large North American ice sheets melted. (This is much of the reason why the IPCC IV report considered it unlikely (something like 90% sure) that there wouldn't be a major change to the gulf stream. That last 10% is enough to be worried about, but it would be some strongly non-linear effects from much smaller amount of fresh water influx or some other mechanism we don't understand.

Originally Posted by lynx

You don't seem to understand the share volume of ice and melt water involved.

Involved in what? These small, short term (but quite significant in human terms), alterations in the heat transfer from the Gulf Stream? The huge, centuries long, major shutdown effects you seem to be referring to are not at issue.

There's a graph here:
The Science of Abrupt Climate Change : Weather Underground