This film by Frank Capra: Frank Capra co-wrote the script for the film, and he was no liberal. He was a conservative Republican, who strongly opposed F.D.R. and celebrated American individualism. But Capra studied chemical engineering at Caltech and put stock in scientific research — before it became ideologically anathema to do that.
One of the narrators declares:
Even now, man may be unwittingly changing the world’s climate through the waste products of its civilization. Due to our releases in factories and automobiles every year of more than six billion tons of carbon dioxide, which helps the air absorb heat from the sun, our atmosphere may be getting warmer.
And is that bad, the question gets asked?:
Well, it’s been calculated a few degrees rise in the Earth’s temperature would melt the polar ice caps. And if this happens, an inland sea would fill a good portion of the Mississippi valley. Tourists in glass bottom boats would be viewing the drowned towers of Miami through 150 feet of tropical water. For in weather, we’re not only dealing with forces of a far greater variety than even the atomic physicist encounters, but with life itself.
I don't want to spoil it but scientist were very aware of our impact on climate in 1958.