I don't know if there's an official consensus in the way you seem to think there is.
My personal point of view is that it seems fairly obvious that dumping tons of shit into the atmosphere is going to have an effect, and is not good for various obvious health and pleasant atmosphere reasons. There are also reasonable arguments about not upsetting existing equilibria that exist.
On the other hand, speculations about disastrous scenarios seem blatantly over-specified and ridiculous to me. We've had dozens of Ice Ages and warm epochs throughout earths' history, obviously not caused by humans, and we have no idea how they worked or ended or whatnot. I think worrying about global warming as a disaster scenario is ridiculous and semi-religiously enforced for political power as well as tribal affiliation.
It depends on what you mean by "disaster" and "over specified." I will add that the IPCC, a body I accept as reputable, predicts a large range of possible outcomes with probability estimates, some of which I think can be fairly categorized as "disastrous." Global warming is a large potential human misery-causer, but not even close to an existential threat. For certain countries, such as the US, it probably won't be that bad, at least until the second half of this century.
If it's worth saying, but not worth its own post, even in Discussion, it goes here.