I think you are misusing the work "theory" in its most strict meaning. In common parlance, when we say we have a theory, we mean I have an unsubstantiated guess, and I'm working on finding corroboration. In scientific literature, we would call that "hypothesis".

A theory when referring to scientific study is the best explanation of observed data which gives useful prediction. Theories can change. Newton's theories or motion are replaced by Einstein's but that does not make Newton wrong, only less precise at extremes of motion.

The theory of climate change should be regarded with the same level of skepticism as the theory of gravity. Neither is perfectly well defined, but they are both more than hunches or guesses thrown about with scant corroborating data. More research will refine both but it is highly unlikely that the understanding of either will be upended by new findings.