SPS requirements
editAccording to WP:SPS, we may use self-published work "produced by an established expert on the topic of the article whose work in the relevant field has previously been published by reliable third-party publications."
There seems to be disagreement on exactly what "an established expert on the topic of the article" means. To me, it seems obvious that the topic of the article Heaven and Earth (book) is just that, the book itself, a work of popular science intended for a general audience. Is their any disagreement with this interpretation?
In this context, an "established expert" would seem (to me) to be any broadly-educated person who could read the book and comment on its contents (and their worth) with authority. The expert reviewer would have a good background in the natural sciences, and experience in some aspects of climate science might also be required.
Other editors seem to be arguing that, for the purpose of reviewing this book, Dr. Stockwell needs to be an "established expert" in all the topics covered in the book. For Heaven and Earth: Global Warming — The Missing Science, this would seem to require an expert in the skeptics view of global warming, from a geologist's perspective, and includes both science and politics. I'm not sure that any of the reviewers we currently quote could meet this requirement. I'm certainly aware that the others are quoted from WP:reliable sources, but, if we set the SPS bar too high, we will exclude other viewpoints, which conflicts with WP:NPOV. So there needs to be some sensible middle ground, to achieve both Verifiability and Neutral Point of View -- see WP:5. Both of these are fundamental principles of the Wikipedia project.