There were never great fears of a new ice age in the 60s/70s.
> This distinction can be made because a serious review of the literature shows that there was no such “scientific verity”. There are anecdotes that can be plucked from the record, primarily from the popular media. But a rigorous review by Tom Peterson and William Connolley (with some minor help from myself) shows that, even as the planet was in a short term cooling trend in the 1970s, concerns about greenhouse warming dominated the scientific literature. The paper documenting our results has been accepted for publication in the Bulletin of the American Meteorological Society, and Doyle Rice did a nice job summarizing the paper last week in USA Today.2
From http://www.inkstain.net/fleck/2008/02/global-cooling-the-und... but there are lots of places where you can find the "we once worried about global cooling" myth debunked.