1. A "global warming alarmist."
2. One attempting to influence others by scaring them with exaggerated claims regarding the potential threat posed by global warming.
3. One who talks about global warming as though it is a "fact" (i.e., scientists have "proven") that fluctuations in global temperatures are caused by the emission of carbon dioxide and other greenhouse gases that result from human actions.
It is a combination of the "warm" in "global warming" and the "alarm" in "alarmists."
I just saw the biggest warmalarm of them all, Al Gore, on NBC telling us we need to piss in bottles or we're all gonna die.
Larry is a geologist who pretends to agree with the warmalarms around him because he wants to keep his job.
John Galt hates warmalarms.