You will have to explain that to Professor Dunlap...

<<Climate Change Denial Books and Conservative Think Tanks Abstract The conservative movement and especially its think tanks play a critical role in denying the reality and significance of anthropogenic global warming (AGW), especially by manufacturing uncertainty over climate science. Books denying AGW are a crucial means of attacking climate science and scientists, and we examine the links between conservative think tanks (CTTs) and 108 climate change denial books published through 2010. We find a strong link, albeit noticeably weaker for the growing number of self-published denial books. >>

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3787818/