Yesterday, the temperature in my neighborhood in San Francisco reached 95 degrees. (Our typical weather this time of year is high-60s.) I'd be happier about putting on flip-flops and heading for the beach today if I didn't know that the hot weather here and across the world this summer is clearly due to global warming.
For anyone looking to get up to speed quickly on climate change, I strongly recommend Tim Flannery's recent book The Weather Makers. Flannery goes broader and deeper than the recent Al Gore movie—with more detail on the hard science, as well as potential solutions. Frightening, but essential reading.