Here is what the ADL said about him: "University of Alabama-Huntsville Professor Roy Spencer’s analogy of proponents of global warming to Nazis is outrageous and deeply offensive. This analogy is just the latest example of a troubling epidemic of comparisons to Hitler and the Holocaust. It has become too common to use comparisons to the Holocaust and Nazi imagery to attack people with opposing views, whether the issue is global warming, immigration or stem-cell research."
And it gets even more interesting. Here is part of a review by Thomas Sowell of the book Who Really Cares by Arthur C. Brookes:
"What is the reason why some people are liberals and others are conservatives, if it is not that liberals are more compassionate?