I think you have hit something on the head. If I had to pick the tipping point for science as a universally respected institution, it would be the publication of "Unsafe At Any Speed" by Ralph Nader. That was where science was clearly subjugated to politics.
Some time after that, Nader took over Consumer Reports and politicized it. Instead of science serving to provide information, it became a tool to justify political intervention in everyday life.
I am fairly certain that at least some of the global warming statements are true, but science has been so thoroughly discredited as an objective source of information, that debates are just shouting matches.
Dr. Robert Stadler from Atlas Shrugged is a classic example.
Wow. Something else to agree with you on; especially the global warming issue. I don't know many meteorologists that agree with it and I've studied it in my met classes and talked to a few meteorologists at the NWS. It's a real hot button for them.
I think the "better living through chemistry" era did some damage to the credibility of science also and medicine is partly to blame for it. In the mind of the public, there is not much difference between the two. Many pronouncements were made as fact and later found to be wrong. I think this has cut into the general credibility and trust that science once had with the public.
I'm not sure what the answer is for scientists to gain back that trust; it's probably something that the scientists have to figure out themselves. But it is going to be a tough battle because there is not much way of controlling what special interest groups do with the information published by the scientific community.