Well, good on him. Most of the climate advances in the US to date have been accidental, not policy driven, but I wouldn’t blame Obama for this failure. His attempts at delivering substanital climate action policy have been repeatedly stymied in Congress and the courts.
This being a lingering issue of urgent need, in which he has failed to substantially deliver, he does need to close his presidency by turning this tide before he leaves office. Any such success hinges absolutely on him partnering with China in coming months, whereby the US and China agree at the highest level to commit, in a bipartisan manner, in the interest of the world.
There is an expectation that this will be his crowning success. Failure to do this will render him a failed president.