All we've ever received are probabilities for different events, and probabilities for their magnitude. You're absolutely right that it's far less satisfying than most other domains of science. If these possible events didn't have very important consequences for humanity, no one would be so anxious about reporting their speculative predictions.
This is perfectly valid and fine, science is always about probabilities and intervals, never about exact values. BUT science goes to great lengths to define the accuracy of its result. You can say that exact science is science that can tell exactly by how much it is wrong... Now these confidence intervals of the results is something that never gets quoted and explained to the public when it comes to the climate issue. The only true scientific talk I attended about climate simulations gave +2 degree prediction in the next 50 (or was it 100?) years with a "one sigma" error of 2. I think their error estimate is very optimistic, after I heard how they calculate it, but giving them the benefit of the doubt, it is 50% chance that the effect will be LESS than 2 degrees. More over, it means about 15% chance (1/6) that not only we will not experience warming, but experience cooling instead.
This is very fine and the correct way to present scientific results, but this is not the way the public hear about it. Politics, media and dishonest publicity hungry scientists turn it into a True/False statement: The models (that they have to run many times and take a mean of the results because the solution does not converge) predict 2 degree warming!!!
The even bigger mystery in such complex calculations is the error due to what is not in the model. Errors due to simplification of equations, partial data, calculation "short cuts" etc. can be estimated and included in the final uncertainty. What you don't know is if there are processes that are important and were not even considered, or done in a wrong way. This latter source for unknown error is the real core of a good scientific discussion. The public discussion got stuck way before that.
The media feed on such crap like flies on shee(i)t. Dis-informing the public is an art form now. I remember about two years ago a big headline about research revealing that proximity to certain factories DOUBLES(!) the chances to develop some kind of tumor. Sounds scary indeed. But when you check the absolute numbers (not quoted in the media report of course), it increased it from 1/80,000 to 1/40,000. Better not leave the house then, it is not safe anymore.