claim: a [ cloudcover ] change in the Tropics could lead to a negative feedback in the global climate, with a feedback factor of about –1.1, which if correct, would more than cancel all the positive feedbacks in the more sensitive current climate models ( Lindzen et al.
evidence: The feedback due to water vapor is a major factor in determining how much warming would be expected to occur with increased atmospheric concentrations of carbon dioxide, and all existing computer models assume positive feedback — that is, that as the climate warms, the amount of water vapour held in the atmosphere will increase, leading to further warming.