From the Introduction:
In science, there is an art to simplifying complex problems so that they can be meaningfully analyzed. If one oversimplifies, the analysis is meaningless. If one doesn't simplify, then one can not proceed with the analysis. When it come to global warming due to the greenhouse effect, it is clear that many approaches are highly oversimplified.
The first section of the paper presents Lindzen's analysis of where the IPCC and its supporters have oversimplified and why the conclusions they have thus drawn are in error. The second section presents Lindzen's analysis of observed data which has led him to state "serious and persistent doubts remain concerning the danger of anthropogenic global warming despite the frequent claims that the 'science is settled'." Lindzen attempts to make the science accessible to an intelligent layman --but be prepared to work a bit as he presents a level of detail which goes beyond the usual simplifications.
Here are excerpts from his concluding remarks:
Using basic theory, modeling results and observations, we can reasonably bound the anthropogenic contributions to surface warming since 1979 to a third of the observed warming, leading to a climate sensitivity too small to offer any significant measure of alarm--assuming current surface and tropospheric trends and model depictions of greenhouse warming are correct. The virtue of the approach presented is that it offers testable points for assessing the arguments...
What this paper attempts to do is point the way to a simple, physically sound approach to reducing uncertainty and establishing estimates of climate sensitivity that are focused and testable. Such an approach would seem to be more comfortable for science than the current emphasis on models, large ranges of persistent uncertainty and reliance on alleged consensus. Hopefully, this paper has also clarified why significant doubt persists concerning the remarkably politicized issue of global warming alarm.
Throughout the paper, Lindzen's statements are straightforward and clear. His tone is objective. His points stay focused on explaining the science behind how and why he disagrees with the conclusions of the IPCC. He offers a reasoned critque of the analysis and conclusions presented in the 4th Assessment Report, and then offers specific recommendations how more accurate conclusions can be drawn. No attempt is made to propose any political action or government policy. It is work such as this which will bring us closer to a real understanding of the effects humans have on climate.