Global warming nonbelievers can be found just about anywhere—from your relatives' Thanksgiving dinner table to Congress. Learn to tell the lukewarmers from the garden-variety deniers with this handy cheat sheet.
Flat-out deniers: Argue that the world is no warmer today than it was during the Medieval Warm Period of 950 to 1250; some accuse scientists of conspiring to put their instruments in hotter areas to skew the readings.
Mathletes: Live to find faulty math in climate change studies.
Sunspotters: Believe the planet is getting hotter, but blame natural phenomena like water vapor, volcanoes, solar flares, clouds, and cosmic rays—not people. Proposed solution? Install A/C (PDF) or find a nice shade tree. See: Rep. Joe Barton (R-Texas).
Lukewarmers: Acknowledge that the Earth is getting hotter, but it's not a big deal. Others argue that it might even be a good thing: See: Rep. Joe Read (R-Mont.), who said that "global warming is beneficial to the welfare and business climate of Montana."
The Rapture-ready: Contend that the planet cannot be warming because it was not foretold in the Bible—and even if it were warming, good news! The end times are upon us. See: Rep. John Shimkus (R-Ill.).
Photos: US Congress; Read: Montana Legislative Information Service