The Great Kerry Debate. The New Republic has asked me and my former Phoenix colleague Jon Keller, of WLVI-TV (Channel 56) and Boston magazine, to debate the merits of John Kerry's candidacy. I get to go first, so have a look.

It's warmer, so we're colder. This ungodly cold winter has provided plenty of smirking material for those inclined to dispute the reality of global warming, and of the likelihood that human activity is making it worse.

So by all means read this New York Times op-ed by Harvard Medical School's Paul Epstein. Epstein observes that worldwide warming, paradoxically, will make the earth colder in some places - like Boston, for instance, or New York, where Al Gore was recently mocked for delivering a speech on global warming in the midst of a cold snap.

If you want to go deeper, this indispensable article was published six years ago in the Atlantic Monthly. According to the piece, by scientist William Calvin, the localized effects of global warming could be catastrophic. For instance, warming could halt the northward flow of the Gulf Stream, making Northern Europe as cold as Labrador.