New Ice age triggered by Global Warming: What could we do?

Great Debates
1

Watched a rather scary show on the Science Channel last night that was discussing the possibility of a new ice age triggered by global warming. One ‘scientist’ on the show said that there is as much as a 50% chance(!) that within the next 6 decades there will be no sea ice during the summer…and that this will cause the great ocean conveyor to completely stop. What this will mean seems to be (at least as far as the show went) still up in the air, but the consensus on the show is that this would trigger a new ice age (sort of like the movie The Day After Tomorrow…at least it appeared to be saying similar things).

Ok, so I have no idea if this scary prediction is real science or standard TV sensationalism…I just don’t know enough about the underlieing science. I have to admit that the idea that global warming will trigger an ice age doesn’t seem intuitive to me, but I can see how if it DOES shut down the flow of cold and warm water that it at least seems plausable.

For debate though I’d like to assume for a moment that it WOULD trigger an ice age…and a bad one. What would be the effect of this? How rapidly would it happen (the show never did answer any of these questions)? Could humanity survive? Could modern civilization survive? Could we use our technology to not only survive and continue but…is there anything we could do about it (once it starts)?

Not for debate but for my own education, how plausable is this? What effect would the accumulation of green house gasses have on this situation? After all, if the global temperature is rising, how would this effect an ice age? In the past (I assume) when there were ice ages I assume there wasn’t also massive amounts of green house gasses at the same time.

Another quick question I had from the show (again, not necessarily for debate but for my own education) is that they claimed that the relative climate stability we have had for the past few centuries is actually a huge anomoly…that at almost no period in (geological) history has the climate been so mild AND stable for so long a period. Is this true? I always thought that the earths climate in the past had extremely long periods of stability punctuated by (relatively) short period (again, in geological time) of fluxuation. Wasn’t the climate stable for millions of years during the dinosaur periods for instance?

-XT

2

Lots of stuff to be said here, and I don’t have the climatological expertise to give the thorough scientifically-documented answers you need.

First point: we’re in an Ice Age, right now, compared to the planetary norm over geologic time. Look at Greenland, Antarctica, Baffin and Ellesmere Islands. Granted it’s a regression from the ice-covering-Canada-and-Scandinavia and tundra on Long Island and in Bavaria sort of thing we think of as “the Ice Age,” but for those ice caps to exist at all is anomalous on the overall historic picture. The Ordovician, the Jurassic, and the Eocene, to take three “normal” periods somewhat at random, did not have any ice cover anywhere to speak of (as far as we can tell).

There have been at least four, and probably five or more, advances of ice into the Northern Temperate Zone during the current Ice Age, during something like a million years, with breaks resembling the present or slightly warmer between them. Antarctica seems to have been iced over for about 15 million years.

However, casting back in geologic time, this Quarternary Ice Age is the third known one in geologic history. There was a major one, focused that time on the Southern Hemisphere, during Permian times (and overlapping into the Pennsylvanian/Carbonifereous and Triassic as regards its overall effects). And one towards the very end of pre-Cambrian time, called the Varangian after the region in Russia where its effects were first observed, that may have been far more severe than either of the other two.

Intriguingly, these Ice Age events occur approximately once every 280 million years, closely correlated with the time it takes the Sun to finish a complete orbit of the center of the Galaxy. Whether that’s coincidental or related is a most intriguing question.

Now, as to how the process is supposed to work, and why, counterintuitively, global warming might lead to Ice Age ice advances… (Note that this is expounding something theoretical and not fully proven as if it were.)

It’s important to remember that global warming refers to climate rather than to weather. It’s saying that additional energy is being pumped into the “terrestrial heat engine.” This energy in turn can create more wind and more evaporation, resulting in a higher atmospheric load of moisture and a more energetic atmosphere moving that moisture from over the warm oceans to land areas. Result of this would be more and bigger storms. (Think about the 2005 hurricane season in this regard.)

But further, let’s take a look at the colder areas of the planet. There’s apparently more net melting of ice in Greenland than has been the case (obviously, some melts and some freezes annually, but in an equilibrium that has now been disturbed). Further, the Arctic Ocean has been frozen over [save a few small areas like the Norwegian coast and Murmansk] for since “time immemorial” in terms of history – and part of it, in the Beaufort Sea, has been melting in the past few years.

Remember that the Arctic Ice Pack is effectively a desert climatologically, even though its geographically ocean – the ice prevents spray, evaporation, etc. And cold air carries very little moisture, resulting in minimal precipatation (i.e., snow, sleet, etc.) in and around the Arctic Ocean. There seems to be some evidence that each ice advance was preceded by open sea in the Arctic. The logic here is that the open sea permits more taking up of moisture into the atmosphere, loading the cold air with as much moisture as it can hold – which it will then dump on adjacent land. The higher albedo of the snow cover reflects more solar radiation, meaning less is absorbed to melt it, allowing further buildup in a reinforcing process that results in ice cover and eventually continental ice caps. At some point, the cycle is reversed, heat evaporates the edges of the ice pack, which retreats, exposing more land to additional heat, and causing a rapid retreat and the pluvial (very wet) post-glacial periods one sees in end-of-Pleistocene maps with gigundo lake coverage from Manitoba to Montreal and including much of the Great Lakes states in the U.S.

Now, somebody else can come along and say how probable this is (or is not) and assign actual numbers to the information I’ve given (or its debunking).

3

I’ve never heard of a “Science Channel.” Do you mean the Sci-Fi Channel?

4

The Science Channel.

5

You saw the TV show, now read the trilogy: Kim Stanley Robinson’s Forty Signs of Rain. There are two more books after this one, detailing pretty much what you just saw on the tube in a fictional setting.

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Wow…great answer Polycarp! One of the things they said on the show (wrt the why of an ice age during a period of global warming) is sort of related to part of your post. Basically (accordig to the show), the rapid melting of sea ice causes the local salinity to decrease…making the water less dense. Appearently the norm is that warm water rises and cold water sinks (fairly obvious), but if the water is less dense the cold water doesn’t sink…causing the conveyor to slow down and even stop. This stopping of the great conveyor seemed to be key to triggering an ice age.

-XT

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So why doesn’t the sea ice re-form as soon as enough snow covers the surrounding land to lower the average temperature again?

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Beats me…I was hoping to learn that kind of stuff in this thread. All they said on the show was that the relatively temperate weather in England, northern Europe and North America is because of this great conveyor…and if it shuts down then that weather will not hold and we’ll get ice age conditions in all those place. And they SEEMED to say it would be for a LONG time too (like thousands or tens of thousands of years).

-XT

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I’d like to know more on this, of course. My knowledge is that of a curious layman. I’d presume the reversal doesn’t happen for the same reason it takes a while to stop a speeding railroad train – there’s a momentum to the buildup, which must be reversed.

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My impression is that there it is not expected that the halting of the thermohaline conveyer will lead to an ice age. What it could lead to is colder temperatures in Europe and possibly the northeastern part of North America. However, even the extent to which this would occur is debatable both because it would be competing with the general warming due to greenhouse gases and because there is some claims that the warming effects of this current might be somewhat overstated…There was a recent paper that used climate model simulations to suggest that the amount of warming that the circulation provides to Europe is overstated…and that only perhaps for the most northern areas (e.g., northern Scandinavia) is there strong warming produced by this. However, I am not sure what sort of reception this paper is receiving among the scientists who study this.

At any rate, the main things to worry about with the shutting down of this circulation would be some pretty rapid and dramatic changes in climate in some regions, including a possible significant cooling in parts of Europe. I think it could also pretty seriously alter rainfall patterns. But, I don’t think the triggering of a global ice age is generally believed to be in the cards.

Here is a FAQ from Union of Concerned Scientists put out when the movie The Day After Tomorrow was released:

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Here is a very recent popular account by one of the authors of that work saying that the effect of the Gulf Stream is overstated. [url=]Here is a News Focus piece in Science (that non-subscribers might only be able to read the summary to) discussing the publication of the original scientific paper.

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Hmmm…I think that you would actually have to be psychic to read that piece from the empty link that I gave…Try [url=http://www.sciencemag.org/cgi/content/full/297/5590/2202]this](]Here[/url).

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Great post Poly… Not much for me to add except one small piece of the puzzle.

It should be obvious to the meanest intelligence that there is no coincidence at all. The ice ages occur due to fluctuations in the current density from the galactic core! :smiley:

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Er, you DO realize that many disagree about the issues of global warming, right? Hell, there are more theories than you’ll ever see on the Science Channel.

Nobody in the mainstream really knows what caused the first ice age. But I’ll tell you: Venus. A massive discharge created two big hurricanes on our poles, sucking up the ocean water and quickly freezing it. The salt was pulled up into the atmosphere and towards the lower latitudes where it helped the electricity in those areas to discharge through the ionosphere much more easily.

THAT’S what causes an ice age, but it comes with a price. Many die, much of the charge that was present before the event is no longer present after, so a quick cooling of the Earth can only happen so many times before life can no longer exist.

If you don’t believe that, at least understand that what you saw on the Science Channel is crap. Global warming causes another ice age? Riiiiight.

15

Do you have any likns backing some of these assertions?

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There’s so much stuff you’d have to take a course on it. http://www.thunderbolts.info is a good site to get started on the Electric Universe theory. Once it begins to dawn on you how the Universe works, then you can start understanding global warming and ice ages.

17

Ah. So Venus causes ice ages.

Well, then there’s a simple solution. We just have to send a team of drillers on the space shuttle to Venus (preferably led by Bruce Willis), insert a nuke, and blow up this dangerous 2nd rock from the sun.

18

I saw the same program (we got it on the History Channel) several weeks ago. One thing I picked up on is that, if global warming becomes severe enough, my beloved Denver will take on the climate of Phoenix. That thought has plagued me all summer long because we are enduring one of the driest, hottest summers on record. Two years ago we thought we’d seen the end of a six-year drought here in eastern Colorado; turns out the wetness was the anomaly and the dryness is the norm. Today we hit 109, and smoke from the prairie fire southeast of town cast a yellow pall over everything. Climate change is very much on everyone’s mind in my neighborhood these days.

19

If you want a decent novelization of a Global Warming induced, environmentalist helped Ice Age, read Fallen Angels by Larry Niven. Specifically, read chapter 7 . The book is typical pulp sci-fi (in fact the protagonists are sci-fi fans who have been forced into hiding) but it is mildly entertaining.

20

I’ve always thought that if the glaciers come marching south from Canada, I’d put my house on rollers and let the glaciers push me someplace warm.