Crichton makes several attempts to cast doubt on scientific evidence regarding global warming. First, he highlights the "urban heat island effect." Crichton explains that cities are often warmer than the surrounding countryside and implies that observed temperature increases during the past century are the result of urban growth, not rising greenhouse gas concentrations.

This issue has been examined extensively in the peer-reviewed scientific literature and dismissed by the vast majority of earth scientists as an inadequate explanation of observed temperature rise. Ocean temperatures have climbed steadily during the past century, for example—yet this data is not affected by "urban heat islands." Most land glaciers around the world are melting, far away from urban centers. The Intergovernmental Panel on Climate Change, using only peer-reviewed data, concluded that urban heat islands caused "at most" 0.05°C of the increase in global average temperatures during the period 1900–1990-roughly one-tenth of...