I just got back from seeing the movie The Day After Tomorrow. It was a decent movie, fairly action packed and the science wasn’t TOO out there (I’ve heard of the sudden climate shift theory, though I don’t remember off the top of my head the name of it or all the particulars). I don’t want to debate the movie though. I only want to ask the question, what do you think would happen if the Earth suddenly went through a climate shift causing the next ice age to rapidly begin? What would countries like the US and Canada do? Half of the US would be a write off, and all of Canada would be a total loss. I assume we would be forced to completely abandon all or most of the northern cities and states…no idea even how far down. The Carolina’s? Georga? In the south west, perhaps all the way to Utah/Nevada?
What would they do (and where would they go) in Europe? Again, half of Europe would be a total write off (wouldn’t it be?)…perhaps as far down as the middle of France? How would the climate shift in the equator nations? North Africa? The Middle East? Would we be able to squeeze in any part of our population into those areas, or would potentially billions die? What about China? What would the climate be there? And where would the Chinese population go if part or most of their nation was also under ice and snow? Also, a question…would the glaciers rise from the south as well as decend from the north? Would south america and southern africa also be covered in ice? What about Austrialia?
Anyway, feel free to discuss the science behind climate shift, give theories as to how far down the ice would go (lets assume for the purposes of debate the ice age would be as bad as the last major ice age that covered most of Europe and North America).
If Civilization III is any indication, it means you have to move a lot of Engineers to costal cities.
If an Ice Age started? Well, we probably wouldn’t notice it for a while. Even if it were in the blink of a geological eye, we’d be long dead and rotten before the glaciers reached NYC.
I dunno, start researching what the climate was like where in the last ice age. I know plenty about the northern hemisphere, but I’m not so certain about the middle of the planet. I’d presume that it would become much more habitable.
Well, for one thing, the Sahara desert belt moves north to the Medditeranean sea, turning the Sahara into a grassland. This opens alot of new ground for human habitation. I imagine that there would be similar shifts in the loacations of deserts throughout the world, some good, some bad.
The shifts would probably happen slow enough for people to adapt. I don’t think anyone would die from climate shifts, but instead would die from wars and other related human stupidnesses. People are very fond of their immaginary lines in the dirt, and get all antsy when people try to cross them.
The moderating mechanism of Earth’s temperature is the heat stored in the oceans. Calculations made by Sir Fred Hoyle in 1980 determined that this stored heat would be exausted in 100 years at the onset of an ice age. Then the engines of the great oceanic rivers like the Gulf Stream would cease flowing and humanity would be forced to out wait another 1000,000 years of ice.
However…
Sir Fred had a good plan for storing up heat in the oceans against this enventuallity, one that would off set the loss of heat that would be reflected back into space by the increase in albedo of glacial ice. This plan could be put into effect in about 10 years.
However…
I forget how the plan was supposed to work. I will go to the library monday and find the book “Ice” and report back if this thread is still viable come Tuesday.
If you want an idea how things would look if we were facing the same sort of conditions present during the Last Glacial Maximum circa 21,000 calendar years ago (18,000 [sup]14[/sup]C years ago), have a look at the vegetation reconstructions posted on this page. A more detailed text description and maps of individual regions are also available. Reconstructions like these are produced mostly from pollen data; in the case of the ice coverage, extent is determined through glacial deposits themselves.
During a glacial interval, the world is actually a drier place overall, and is not notably more hospitable. The Sahara does not vanish, but gets larger, along with desert areas in central Asia. (The greening of the Sahara took place after most of the ice from the last ice age retreated; scroll down this page to the discussion for 8,000 [sup]14[/sup]C years ago). Some coastlines will shift outward as ice sheets grow and sea levels drop, leaving current coastal cities far from shore (e.g., if NYC were not covered by ice, it could lie as much as 100 miles from the nearest beach; see the maps in the second link above for the positions of the new coastlines). Ice sheets don’t form in Australia or Africa, although mountain glaciers may grow, largely because it’s too dry. Large glaciers/small ice sheets may form in the Andes in South America, but again don’t achieve the size of northern hemisphere for a similar reason.
Without getting into a debate about the movie, I will add that the decline to anything like Last Glacial Maximum conditions WILL take tens of thousands of years, simply because it takes the ice sheets that long to begin growing and expand to the appropriate size. Unpleasantly disruptive weather could certainly rear its ugly head before then, and much more abruptly, and would be of more immediate concern than the ice.
With all due respect to Sir Fred… I suspect his ideas on this score were rather off the mark. It sometimes happens that prominent scientists, late in their careers, decide to branch out into new areas in which they have virtually no prior knowledge, and they wind up getting airtime for ideas that would otherwise be considered remarkably naive. I’m interested to hear your report, Milum, but given what you’ve said so far I’m not expecting anything particularly useful from Sir Fred.
I see, Sunfish, sorta like the Nobel Prize winning physicist Luis Alvarez cross-dressing and pointing sleeping geo-paleontoligists towards the 150 mile hole in the Gulf of Mexico that might have been instrumental in eliminating the awful dinosaurs so that ultimately mankind could rule undisturbed without being eaten by slimy creatures with with big teeth and peanut brains.
We’ll see, Sunfish, but remember, math doesn’t change whether done by the cognoscenti or people who just know math.
This IS the same Fred Hoyle that believes that the reason nostrils slope downwards is to ward off the germs from outer space right? Figures can be massaged any way you want. Just because you win a nobel in one area does not mean you can be trusted to make sound, impartial judgements. Look at Penrose and his Quantum Theory of Mind for example.
Here is a link from the Union of Concerned Scientists discussing abrupt climate change, particularly in light of “The Day After Tomorrow”. While abrupt climate change, triggered by the forcings that humans are putting into the climate system, is a serious potential issue, it is important to distinguish fact from fiction particularly in light of this movie.
Note, in particular, this part:
Of course, significantly colder temperatures across much of Northern Europe and, to a lesser extent, the eastern U.S. and Canada, would cause a dramatic change for some pretty populous areas, it is important to distinguish this from a planet-wide ice age scenario.
Milum said…“Sir Fred had a good plan for storing up heat in the oceans against this enventuallity, one that would off set the loss of heat that would be reflected back into space by the increase in albedo of glacial ice. This plan could be put into effect in about 10 years.
However…
I forget how the plan was supposed to work. I will go to the library monday and find the book “Ice” and report back if this thread is still viable come Tuesday.”
Oops! I was a little off in remembering Sir Fred Hoyles grand plan. In essence it was this…
Ice ages are triggered by some agent that significantly reduces the amount of solar radiation that the Earth receives from the sun. (bolide impact, widespread volcano eruptions, etc.) In this event all hell breaks loose. The land mass cools off faster than the oceans, increasing the temperature difference between the two, which translates into a nightmare world of hurricanes, tornados, and thunderstorms with continuous lighting strikes that last until the heat stored in the oceans is depleted. This equalization of temperature only takes about ten years, then the deep freeze sets in ; snows accumalate and spread over the land surface and reflect more and more of the sun’s radiation back into space.
Great ocean rivers, like the gulf stream, cease flowing , rainfall lessens and sealevels fall and the poor creatures of earth settle in for a 100,000 wait for the return of warmer times. Brrrrrrr!
But Fred had a plan, a plan to save Earth, a grandiose plan, one that would take only 2,000 or 3,000 years to implement if we started right now.
Fred planned to warm up the world’s oceans back to the warm temperatures of the Mesozic, the times of dinosaurs, back when our seas were hot enough to withstand ten years of diminished sunlight without surrendering to an advance of packed ice. Those were the good old days before the advent of periodic glaciation.
Using the energy of the sun to fuel the pumps Sir Fred planned to pump up cold water from the bottom of the sea to the surface and slowly warm our oceans up maybe ten or fifteen degrees.
You gotta admire Fred Hoyle, he was a man of vision, a man who thought big, not like the cry babies of science among us today. I’d feel better if Fred was here today to man the pumps.
And the fact that he was almost completely and utterly wrong wouldn’t bother you in the slightest? Interesting.
There are two fragments of the quote above that are correct: land does cool off more quickly than the oceans owing to differences in thermal capacity, and snow does reflect more of the sun’s radiation back into space than bare ground or ice-free water would, because snow has a higher albedo (reflectance). Everything else in that quote is pretty much wrong, and illustrates beautifully the problem of someone trying to intuit non-linear climate processes from a very simplistic and naive starting point. It also illustrates very well what happens when theory-oriented people fail to take the actual data into account. (BTW, Luis Alvarez had his geologist son, Walter, to help keep him on track, so he’s not really a good example of a famous scientist making a huge solo contribution to another field.)
I know you’ve paraphrased, Milum, but I assume you’ve captured the essence of what Sir Fred was saying, so I’ll address what you’ve written here.
**Ice ages are triggered by some agent that significantly reduces the amount of solar radiation that the Earth receives from the sun. (bolide impact, widespread volcano eruptions, etc.) In this event all hell breaks loose. **
This is really the key issue, so I’m going to spend some time on this.
Fred Hoyle was extremely fond of dust - interstellar dust, organic particles and possible interstellar microbes, to be specific. Over a period of roughly 30 years, he and his colleagues have published some 88 papers on the topic. Tucked away in there were four papers* on the role of interstellar dust and climate change on Earth, including the onset of ice ages.
Sir Fred’s view was straightforward - if you put enough dust of the right particle size into the Earth’s atmosphere, you’ll block incoming sunlight and trigger sudden climate change. Because the right particle size (0.1 microns) was crucial, according to his own calculations, not just any dust would do. Interstellar (“zodiacal”) dust tended to be just the right size for maximum reflectance, so he favored passing comets or interstellar patches of dust as sources, although in a pinch, bolide impacts and volcanic eruptions here on Earth might be sufficient. The dust could be either in the atmosphere or in the oceans, it didn’t matter.
In fairness to Sir Fred, dust has been (and continues to be) of interest to climate modelers trying to forecast future climate trends, as well as reconstruct the past. However, terrestrial dust is the focus, as part of the response to a cooling climate (cooler = drier = more dust in the atmosphere). Relying upon interstellar dust sources to trigger ice ages introduces a sort of capriciousness that doesn’t jibe well with the periodic nature of certain climatic trends over the longer term (see, e.g, this discussion on Milankovitch cyclicity). Moreover, although our knowledge of climate processes and their interactions is still incomplete, it was certainly clear by the early 80s that different factors (also called climate forcings) work in concert to produce climate, and that they don’t necessarily interact in the most obvious ways.
In addition, it really is pretty easy to test the idea that interstellar dust (or any suitably fine dust) triggered catastrophic cooling and the development of ice ages in the Earth’s past; all we need to do is examine the geologic record for any indication that a large influx of dust directly preceded an ice age. Let’s look at the age estimates for the onset of glacial intervals in the last billion years (Ma = million years ago):
~750 Ma - Sturtian glaciation
~600 Ma - Varanger/Marinoan glaciation
~444 Ma - Ordovician glaciation
~299 Ma - Permian glaciation
~ 34 Ma - onset of global cooling leading to growth of Antarctic ice sheet
~6-10 Ma - Greenland ice sheet formation and expansion
1.8 Ma - Pleistocene glaciation begins
There is no periodicity evident at this scale that could account for these glacial intervals being caused by, say passing through a particularly dusty part of the galaxy, or the periodic return of a comet. Well, there could have been random events, you say. Then we sample the geologic record in the right places to look for indicators of cosmic dust. But what we come up with instead is a relatively stable background flux of helium-3 in bulk sediments (a proxy for cosmic dust influx ) over geologic time - no spikes related to onset of glaciation.
All right, if cosmic dust doesn’t do the trick, how about terrestrial dust? Let’s consider the timing of some bolide impacts that were large enough to be (potentially) responsible for mass extinctions, and thus presumably could have thrown the requisite amount of dust into the atmosphere:
~375 Ma - Frasnian-Fammenian impact
~251 Ma - end-Permian impact
~214 Ma - Manicougan Crater impact
65 Ma - K-T boundary event
Note that the timing of these events is off w/r/t the onset of glacial intervals. Moreover, an interesting little study that looked at the fine-scale timing of events around the K-T impact event (using the apparent constant background flux of cosmic dust to constrain time!) shows that the climatic impact of the K-T event lasted on the order of a few years to decades only, much too short to overcome global climate inertia and bring on an ice age. Indeed, it’s obvious from the geologic record that it didn’t happen.
Bottom line - cosmic dust does not play a role in triggering glaciation on Earth.
Touching more briefly on other statements:
The land mass cools off faster than the oceans, increasing the temperature difference between the two, which translates into a nightmare world of hurricanes, tornados, and thunderstorms with continuous lighting strikes that last until the heat stored in the oceans is depleted. This equalization of temperature only takes about ten years, then the deep freeze sets in ; snows accumalate and spread over the land surface and reflect more and more of the sun’s radiation back into space.
Sir Fred is implying that the rate heat loss over land has to increase to such a significant degree that the differential between heat over land and the current heat capacity of the ocean alone will drive a huge increase in storms. Okay, so… where does that all that heat go? How is it shed from the Earth so that the energy is permanently lost to the climate system in just 10 years’ time?
The answer is that it simply wouldn’t be possible, short of pretty much blocking all incoming solar radiation at the top of the atmosphere (for our purposes, above the stratosphere). Sir Fred loses sight here of the fact that both positive (warming) and negative (cooling) feedbacks are constantly in play to buffer the climate system. He is in effect assuming that the only relevant forcing is solar radiation, neglecting the impact of various greenhouse gases (water vapor and carbon dioxide being the most prominent), clouds, the huge thermal capacity of the oceans, varying albedo effects as a function of latitude/surface characteristics/surface roughness, volcanic gases, vegetation… well, you get the idea. Not to downplay the importance of the sun here, but it really isn’t the only factor to consider.
Back in the 1970s, Fred might have been forgiven for being ignorant of some of these details; after all, climate modeling was then still in its infancy, and even the first-order climate forcings and their interactions were not well understood. There certainly wasn’t the computing power available to indulge in more sophisticated 3-D climate models, a.k.a. general circulation models or global climate models (GCMs). However, by the 1980s, climate research efforts using GCMs were well underway, and if he had paid any attention to the atmospheric science or Earth science literature on this subject, he would have been well aware of how naive some of his assumptions were.
BTW, I don’t consider it an accident that his last two papers on the topic were published in a journal focused on astronomical matters. If he had submitted to an Earth-science journal, his papers would very likely have been rejected.
The rest of this is just frankly so much b.s. Besides, if we have the energy of the sun available for fueling pumps, there sure as hell is enough solar energy to warm the ocean independently of our “help.” Sir Fred is arm-waving so dramatically here that’s he’s about to take off.
Now, I’m in favor of entertaining all sorts of ideas when you’re brain-storming. Lord knows I’ve done it often enough in my own research, and it can be a LOT of fun. But at some point, you need to do a reality check and make sure you aren’t reaching too far, given the data that are already in hand. IMHO, Sir Fred was in sore need of a reality check, and he never took one.
My apologies for being so long-winded. If you made it this far, feel free to go crack open a beer (yes, I know it’s still morning in the western hemisphere; who gives a damn).
*References:
Wickramasinghe, N.C., Hoyle, F., and Rabilizirov, R., 1989, Extraterrestrial particles and the greenhouse effect. Earth, Moon and Planets 46:297-300.
Hoyle, F., 1984, On the causes of ice ages. Earth, Moon and Planets 31:229-248.
Butler, E.J., and Hoyle, F., 1979, On the effects of a sudden change in the albedo of the Earth. Astrophysics and Space Science 60:505-511.
Hoyle, F., and Wickramasinghe, C., 1978, Comets, ice ages, and ecological catastrophes. Astrophysics and Space Science 53:523-526.
Wow sunfish, yours is an excellent post. Clear, tightly written, and pertinent to the two prongs of the discussion, viz. particulars to the advent of a glacial period, and the deterioration of the individual scientific mind through egoism in the face of new advances in scientific understanding and methodology.
Very impressive. With your nicely clipped, confidant mind and those writting skills you should be able to pick up every paleo-climatologist groupie chick that you meet and get lots of free federal grant money just because you are you and no one else can say that.
Now I did have a couple of minor disagreements with a couple or three of the points you have made but I must leave town for the afternoon. I will think over these disagreements while I ride and will post them here tonight if I happen to return home sober.
but it really isn’t the only factor to consider.