The words "scientifically" and "proven" should not be used in the same sentence without a negative modifier between them . If you think science "proves" anything, then you do not understand how the scientific method works. It determines when and if observations do not agree with theory, and discards or modifies theory accordingly. Theory - even Law - are never considered proven.

Even with something as concrete and established as relativity or quantum mechanics, "proven" is not used.

For a hypothesis as ephemeral and non-predictive as AGW, the word "proven" shouldn't even reside in the same zip code. Look at CMIP5, or the controversy over the Pause. Now, a reasonable person can weigh the preponderance of the evidence and conclude that AGW is happening and is a threat.

No reasonable person would look at the evidence and conclude that the science is settled beyond dispute.