Skeptical Views of Global Warming

The view of most climate scientists is that rising CO₂ in the atmosphere, primarily from human activity, is driving the current increase in global temperature. A recent summary of the case for CO₂ as the main radiative forcing for the human influence on global warming is Collins, et al. An active internet discussion site for climate scientists and others is Real Climate.

But climate modeling is very complex, the stakes are very high, and there are numerous special interests. This situation is tailor-made for controversy. The following are some of the types of objections that skeptics of CO₂-driven global warming raise:

• The CO₂ is not sufficient to drive the currently observed warming.
• The atmospheric CO₂ level has been up to 10 times higher in the past. Why weren't there catastrophic consequences then?
• Much of this century's temperature rise was in early years when industrial emissions were small, and there was a temperature decrease during the postwar economic boom.
• Ice core records show CO₂ rises lagging temperature rises rather than driving them.
• Surface warming is more than atmospheric warming, in contrast to CO₂-driven models.
• The global temperature of t he past century correlates more strongly with solar activity than with CO₂.
• The sunspot activity of our Sun and the associated magnetic fields divert some of the cosmic rays that nucleate clouds on the Earth.