There wasn't any doubt for decades. Normal thinking people understand cause and effect. Understand basic science of greenhouse effect. Understand if energy is not reflected to space it is stored and that you can't do that forever with impunity.
I mostly agree, but I think this falls under the Black and White fallacy. Just because we understand the mechanism doesn't mean that the magnitude is large enough to matter. It could be that clouds or normal volcano erruptions have such a large impact on trapping energy that greenhouse gases don't matter. What you also have to show is that the basic cause is actually sufficient to explain the effect, and that's difficult when it's on a (planet) scale most people never think about.
Many times I see experts spend lots of time explaining the simple casue and effect relationship, only to gloss over the large amount of work they've done to convince themselves that it actually is significant. University PR departments and ads-driven media aren't helping.
