I think you read a "not" in my comment that wasn't there, I'm agreeing with you about what the person you responded to seemed to be arguing for (stop the science because it's not good enough). Which is, as Supermancho points out, nonsense.
Science makes predictions that turn out to be true on incomplete theories and systems all the time. Even if we're missing causes for sinks we can make predictions on what happens when there's more greenhouse gases in the atmosphere as the effect of them are well understood.