It's actually a semi-educated guess.
http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x27242I "predict" that once the northern branches of the Atlantic Thermohaline Circulation "fail", there will be gross changes in the air systems of the northern hemisphere. A huge volume of heated warm air will build up and pool in the polar regions, perhaps surpassing the tropics in summertime heating (all the more possible due to the longer polar summer days). This will lead to a "Zone of Storms", initially at low polar latitudes and during the early winter, but eventually moving lower (to about 40-60N) and becoming a year-round phenomenon. It will be the driving force behind northern continental ice pack accumulation as it "discharges" accumulated heat and water vapor.
At lower latitudes, the heat will dessicate agricultural areas; and little agriculture will be possible in the areas that are perpetually flooded and/or frozen. If we still have enough petroleum-derived fertilizer for high-yield crops, this will cause massive famine on its own.
Of course, if we run out of fertilizer first, it will be a moot point.
I am convinced that this has already started. The temperature-regulating currents in the North Sea have already been observed as failing for the last few, which started at about the same time as the deadly-hot European summers (2001 IIRC). Last year, several of the smaller currents just were not present at all.
In addition, atmospheric dessication is starting, and the decades-long increase in cloud cover reversed itself over the past five years. The water is probably being carried higher into the troposphere, and if anyone looks, I suspect they will find robust high-altitude poleward pseudo-jet-streams getting started.
Northern Polar summertime temperatures have been abnormally high since the late 1990s, and a similar phenomenon is happening in Antarctica, with increased precipitation at the pole, and record melting along the coasts and ice sheves.
This winter may or may not be bad, but with the mechanisms in place, it's only a matter of a few years before weather patterns establish themselves to allow this excess moisture to precipitate out of the atmosphere. The more heat, the more intense the subsequent precipitation and the more driven the storms.
This period will either last as long as a little ice age would (100 to 2000 years) or a couple of millenia, if this is the start of a "true" or major ice age, like the last one, the 100,000-year-long Wisconsonian/Würm glaciation.
It's only a guess, and a wild-assed one at that. I do not forsee a whole lot of climatic effects worth celebrating. But at least I have a lot of company, even if they are not as quick to risk their scientific reputations as I am.
Of course, it helps to not have a scientific reputation to risk!
--p!