The answer is that no-one knows, (the 97% figure quoted so often is a falsehood — Fake news about a Faked Number) and it doesn’t matter anyway: Science is not about Consensus, it is about testing an hypothesis and trying to disprove it, and only by repeated failures to disprove it, is the hypothesis eventually accepted as a fact. Tell me how many Climate Scientists are trying to disprove Global Warming! The tiny few who attempt to use the Scientific method on the AGW hypothesis have been ostracised and ridiculed. Read what Freeman Dyson, the preeminent Physicist of our age has to say about it:

http://www.thegwpf.org/content/uploads/2015/10/benefits1.pdf