What, precisely do 90%+ of scientists working agree on? That AGW exists, and that's all. You won't get 90%+ of scientists to agree on the implications of AGW. In particular, you won't get them to agree that the current computer climate models are Holy Writ, only doubted by the ignorant. The Al-Gore crowd refuses to acknowledge any possibility of error in the climate model forecasts, even though any honest climatologist will admit that the models are imperfect.
Anyone who claims the ability to predict the future behavior of a complex, imperfectly-understood system with 100% accuracy doesn't really understand how the world works.