According to Hitwise, one of the companies that tracks these sorts of things, is saying in a press release today that searches for the search phrase “global warming” are “heating up”: The number of search queries containing the words ‘global warming’ increased 173 percent year over year — growing from 755 unique terms in the four weeks ending February 18, 2006 to 2,059 unique terms in the four weeks ending February 17, 2007.