I think the conclusions were oversimplified and dissenting opinions were not mentioned. I like the book for what it says about groups of people basically needing to adapt to a changing environment. I think it has some worthwhile information in that regard and the case studies were engaging, but I did get bogged down in places. I think the author could have picked up the pace in some of the vignettes and stretched it out a bit in the analysis at the end. Also, I read this for a class that required me to find independent peer reviewed sources. Many of them contradicted the author's anthropological and climatological conclusions. Use it as a parable and you're fine. Look too close and you may get lost in the weeds.