Climate skeptics are often accused of being deniers, but what exactly they deny is never made very clear. In fact, many climate skeptics like, Warren Meyer, accept the Earth has warmed and that part of this warming has been due to manmade greenhouse gasses.
What skeptics deny is the catastrophe — they argue that warming forecasts are being exaggerated by a second, unrelated theory chained onto greenhouse gas theory — that the Earth’s climate system is dominated by strong positive feedbacks and that these feedbacks multiply the incremental warming from greenhouse gasses many times. In fact, the majority of warming from IPCC forecasts is due not to CO2 greenhouse gas effects but to this theory of climate positive feedback. It is with this second theory, for which the scientific evidence is weak, that skeptics have the most issues.