this interesting. It's not been well reported that the earth has actually been cooling, naturally, while what humans are doing is keeping it artificially warm; this was demonstrated by examining atmospheric records from those three plane-free days after 9/11 (no jet contrails to foul the data). Anyway, Da-da's geologic brain (which works about as fast) recalls that, according to ice cores, global warming typically preceded ice ages.
Interestingly enough, it seems glaciers have been GROWING, on Mt. Shasta, Mt. St. Helens, in Alaska, Norway, and in Antarctica over the past 30 years. Note that this is indeed possible with global warming, as local variations will exist and extreme weather prevail (more hot and cold air interactions), but Da-da has always suspected that we were living during yet another interglacial period, and a renowned Columbia University paleoclimatologist just confirmed it.
So what, right? Just put on a jacket and grab your sled? Alas, if an ice age is incipient, it's not the happiest of pictures. Ice age onset can occur very quickly, in a decade, and with growing populations, wacky weather, shrinking crop yields, shorter growing cycles... do the math. Certainly not a reason to panic (Da-da hates panic), but it's something to keep in mind. Worse case scenario: get ready for some do-it-yourself hydroponics. (And NO, not to grow that.) Da-da would actually be relieved by news of a new ice age, so all those gynormous methane deposits stay under the ocean where they belong; unleash methane with rising global temps and you've got... VENUS.
(Note: baseballs tend to catch fire when the planet's surface temp is 600-900 degrees, which makes foul balls reeeally HURT, if not more difficult to catch. AND while it may keep Da-da's hot dog warm, it would tend to make his $10 beer boil. Da-da does not like to pay $10 for boiling beer... unless it's to cook schnitzelgrubers, but that's a whole other planetary system.)
Note: not sure which theory this supports or refutes, but scientists also announced this week the observation of, "the highest level of Arctic ozone layer depletion on record, attributed to colder temperatures in the stratosphere." The upper atmosphere is very interesting, in that it gets colder -- then hotter -- the higher you go, though this is a bit misleading; the higher you go, the less actual particles you run into, but those that you do encounter are indeed like flaming baseballs.
UPDATE: Looks like the sun has finally decided to point South-dominant full time, now, which means that the earth and sun are geomagnetically sympatico. This means that the earth is absorbing most of the sun's output, rather than repelling it. This points to increased volcanism, as evidenced by all the recent volcanoes popping off left and right. If this continues, you'd best buy a warmer jacket.