Given the fact that global warming is a theory due to the records being unavailable for most of mankind's history, due to the fact that many scientists believe that the emissions of just one volcano dwarf man-made emissions into insignificance, I'd say the memo is reasonable and takes a sensible approach to the question.
Given the fact that “green” jobs, “green” technology is not only cumbersome, often ineffective, expensive and can be detrimental to humans who are already vulnerable to starvation, I'd say the memo is quite acceptable..
Finally, given the fact that I find Al Gore's educational background deficient, his morals suspect, his carbon footprint outrageous and his bank account a great deal larger than either his aptitude or inheritance can explain, I'd say I'm going with Sammon. Y'all do as you please, though.
No scientists believe that because it isn't true. What legitimate scientists dispute is that manmande CO2 will catastrophically warm the world. The evidence points to a minor warming only.