As the United Nations Framework Convention on Climate Change met in Cancun, Mexico last week to forge a pact to cut greenhouse gas emissions, the unusually cool weather in Mexico, Europe, and elsewhere gave skeptics the opportunity to poke fun at those claiming the planet is warming. But the truth is that these episodes of cold weather have not tipped the evidential balance toward an overall cooling trend. The World Meterological Organization maintains that global warming remains real in spite of the bouts of cold weather (also see this more technical discussion).
I think many people are misled to believe that episodes of cold weather run counter to the idea of "warming." The word "climate change" is a better phrase than "global warming" as it encompasses the myriad effects of extreme weather associated with the greenhouse effect. Indeed, the U.S. Environmental Protection Agency uses "climate change" as the title of its webpage devoted to the subject. We should follow the agency's example.