Less than 5 minutes in and a young hipster-looking guy says "a lot of these films are warning about global warming,.." as if climate change was a thing in the 70's and before. It wasn't. 'Limits To Growth', one of the classic books of the environmental movement in the 70's, has not one mention of global warming or climate change or anything resembling it. Back then it was all about overpopulation, pollution of the seas and running out of resources. Global warming or climate change hadn't been invented and popularized yet. I'm not sure the thoughts of the said interviewees warrant the running time, but maybe nostalgia is enough to entertain you.