Good post but some of your info is out of date. (1) In the 1980s scientists realized that although the average interglacial period might last 10-20,000 years, the current one, because of variations in orbital dynamics, was more likely to last 30,000 years or so. Still, as Ruddiman has pointed out, usually there is a steady decline from the peak warmth (which happened about 6000 years ago), but in our case something, probably greenhouse gases, has made for warming instead. So while humanity hasn’t staved off an ice age, it has apparently prevented seriously colder weather. (2) No scientist believes any longer in the scenarios you give for more CO2 (carbon dioxide) bringing an ice age. Bryson’s idea of rapidly increasing pollution sounded good in the 1970s before clean air legislation, but now we understand that pollution drops out of the atmosphere in weeks whereas CO2 lingers for centuries. Vegetation is only mildly enhanced by CO2; past a certain point more of the gas fails to do much, as the plant hits its limit on nitrogen and other fertilizers. As for a giant meltwater lake draining into the Atlantic, that can only happen at the end of a glacial period, duh. (There is some concern about the Gulf Stream slowing down anyway, but that will only delay warming in the region and only by a decade or so).
It is indeed the case that warming will bring all sorts of problems, including even more snowfall in some places – warmer air holds more moisture, and it’s at near-freezing temps, not very cold ones, that he worst snowfalls take place. Plus there are, as you say, some signs world-wide of increasing storminess.
For too much detail on all this see http://www.aip.org/history/climate/