Brian Fagan, The Little Ice Age (2000) and The Long Summer (2004).
The earlier book has more celebrity: it was the subject of a documentary on one of the History channels, and the author himself appeared a couple months ago on none other than Jon Stewart's ""Daily Show"--total surprise, as Fagan's paperback edition lay open on the couch next to me! Cosmic, man. Well, it's an absolutely engrossing account of our 1350-1850 cold snap and how it changed history. You'll discover that Bad Weather was a decisive influence on such events as the Mayan extinction, discovery of America, French Revolution, and explains less "cosmic" but no less interesting puzzlements like: Why Britain no longer could produce some of the finest WINES (!) of the middle ages; Why there are now no winter ICEBERGS in the Delaware River that Gen. Washington had to carefully navigate in the famous portrait of his crossing; Why Hans Brinker and his Silver Skates (a favorite story from my childhood) cannot now glide magnificently as he once did over the ice-covered canals of Holland. But of course the greatest positive effect, ironically and in spite of the cataclysmic Irish potato famine, was the great Agricultural Revolution (during the latter part of those centuries) that we are still enjoying today, along with the renewed warm period.
A little too warm. As Fagan points out in the last chapter, global warming and consequent melting of northern ice sheets could again shut down the North Atlantic Oscillation (gulf stream, etc.) and lead paradoxically to another Ice Age, anytime now. It's all VERY precarious right now, and Brian Fagan explains it all admirably. And, by the way, vote for Obama to get AL GORE back on the White House team.
Fagan takes us sort of "back to the future" in his latest book, filling the gap of 18,000 years between the last true Ice Age of the Pleistocene up to the little one above. The Long Summer is just as interesting and informative--here, after all, is when and where civilization developed and we culturally evolved. You will be amazed at how much WEATHER had to do with it. Read this one first, and then, having read both, pick up a copy of Jared Diamond's Guns, Germs, and Steel
(1998) for a total understanding of everything.