The (polite) answer would be yes, scientists come up with science for the most part. That sounds almost tautological. However, that is not how the scientific method works. The theory they come up with now has to stand the test of time. Remember it only takes one piece of evidence to disprove a theory yet no amount of evidence can prove it. Sure a lot of evidence can support, it but never prove it.
Take relativity for example. There is a lot of supporting evidence for both General and Special Relativity. However, send your man to Ganymede (moon of Jupiter) and start communications real time (no delay). All of a sudden Einstein's best is junked and moreover you don't have to know anything about the mathematics of Tensors, Affine connections and Riemann derivatives to do this. Just send/ receive the signal real time. That's all! This property is called 'falsifiability'. This is one way that Relativity is falsifiable simply because one of the predictions of the theory is that nothing, including information, can go faster than C circa 3E+8m/s- the speed of light. If it is not falsifiable then it is not science but a belief. Beliefs are always correct as they are not falsifiable. Karl Popper had some very interesting insights on this and you may wish to read up on this. These even come into sciences like statistics (regression analysis) and how regression models (the hypothesis) relates to the degrees of freedom in the model and falsifiability, but I digress.
One of the big problems with climate science is that there are no universally stated measures by which the 'theory' of GACW is falsifiable like Relativity. Climate scientists have tried stuff like upper atmospheric hot spots but these have been junked by the evidence of thousands of weather balloons. In science evidence always trumps theory.
