I am so sick of hearing the elite media and their favorite Republican call conservatives anti-science and pushing the idea that there is absolute consensus on global warming and evolution.
On the most basic level, these appeals to scientific authority are only valid if the authorities are not significantly biased.
In the case of both global warming and evolution, the scientific establishment is EXTREMELY biased to the point of censoring any dissenting opinion (Expelled! and climategate). Both issues are highly political, and in the case of evolution form the very basis of the naturalistic and athiestic worldview held by many scientists. Making appeals to the authority of scientists who are largely left-wing on these issues is thus a logical fallacy.
Also, direct appeals to evidence are stronger than appeals to authority.