Yes, you have it correct. Maths must be the only area of science where it is possible to prove a hypothesis absolutely e.g. Fermat's theorem. However, for example, in physics quantum theory is just that, a theory. The fact that it started as a hypothesis that explained all the relevant observations and allowed one to make predictions is all we need to make practical use of it . In any case climate change hypothesis is reasonable as far as I can tell because the experimentally observed effects fall within the modelling envelope and make it a working theory and allow predictions to be made. i.e we are in serious trouble if we don't reduce CO2 emissions.
Finally, good on the school kids for drawing attention to the problem. Judging by the totally ignorant response by the "older generation" on HC I think they put them to shame. I have witnessed more intelligent reaction to AGW from farm animals than some of these guys.
