Sachstandsbericht des IPCC
Lindzen worked on Chapter 7 of 2001 IPCC Working Group 1, which considers the physical processes that are active in real world climate. He had previously been a contributor to Chapter 4 of the 1995 "IPCC Second Assessment". He described the full 2001 IPCC report as "an admirable description of research activities in climate science" although he criticized the Summary for Policymakers. Lindzen stated in May 2001 that it did not truly summarize the IPCC report but had been amended to state more definite conclusions. He also emphasized the fact that the summary had not been written by scientists alone. The NAS panel on which Lindzen served says that the summary was the result of dialogue between scientists and policymakers.