New paper finds climate sensitivity to CO2 is 'close to zero'

A new peer-reviewed paper published in Energy & Environment finds there is no agreement between observations and climate model predictions during the last two decades of the 20th century. According to the author, "This finding is shown to put constraints on surface [temperature] trend and Climate Sensitivity, limiting them to values close to zero." The paper adds to several other peer-reviewed publications finding the IPCC estimates of climate sensitivity to CO2 are greatly exaggerated. 

The full paper is paywalled, but a 2011 paper by the same author [S. Fred Singer] is available here and comes to similar conclusions.

Inconsistency of Modeled and Observed Tropical Temperature Trends

S. Fred Singer

¹Science & Environmental Policy Project, University of Virginia, Arlington, VA 22202

Abstract: Consistency or lack thereof between observed temperature trends and those predicted by Global Circulation Models (GCMs) are a contentious though important issue. The lack of consistency between observed and modeled temperature trends has frequently been used to argue against a significant human contribution to global warming - and vice versa. We present here additional and independent evidence that there is no agreement between observed and modeled warming trends in the tropical troposphere during the last two decades of the 20th century. This finding is shown to put constraints on surface trend and Climate Sensitivity, limiting them to values close to zero.