In the course of his article, he makes three statements:
Hitchens: Recent studies show that most polar bear populations are rising.
Fact: Arctic ice is definitely retreating. Arctic ice is the polar bears' habitat. Loss of habitat will force them to migrate and adapt.
A WWF report says: Satisfactory monitoring information has been delivered for fourteen of the twenty populations of polar bears in recent years (see Table 1, page 12). Of these, ten are showing stable population numbers, two seem to be increasing, and two are decreasing.
Hitchens: The world was warmer than it is now in the early Middle Ages.
This is not true.
This figure was prepared by Robert A. Rohde from publicly available data. Source
Hitchens: The most important greenhouse gas by far is not CO2 but water vapour, which is not influenced by human activity at all.While it is true that water vapour has a stronger effect than CO2, since its effect increases with temperatures, and since temperatures are influenced by fossil fuel CO2, human activity does have an effect on water vapour.