I've seen this argument trotted out in our comments far too many times. Let's put a fork in this one:

The supposed "global cooling" consensus among scientists in the 1970s frequently offered by global-warming skeptics as proof that climatologists can't make up their minds is a myth, according to a survey of the scientific literature of the era. The '70s was an unusually cold decade. Newsweek, Time, The New York Times and National Geographic published articles at the time speculating on the causes of the unusual cold and about the possibility of a new ice age.

But Thomas Peterson of the National Climatic Data Center surveyed dozens of peer-reviewed scientific articles from 1965 to 1979 and found that only seven supported global cooling, while 44 predicted warming. Peterson says 20 others were neutral in their assessments of climate trends. The study reports, "There was no scientific consensus in the 1970s that the Earth was headed into an imminent ice age. "A review of the literature suggests that, to the contrary, greenhouse warming even then dominated scientists' thinking about the most important forces shaping Earth's climate on human time scales."