That’s the view of legal scholar Eugene Kontorovich:

The United States never properly joined the accord: It is a treaty that requires the advice and consent of the Senate. …

Two features cut heavily against it being treated as the kind of arrangement that can be entered into by a president on his own authority. First, it has a four-year waiting period for withdrawal, quite unlike traditional executive agreements. Second, it is a large multilateral deal, and the other parties apparently believe it requires domestic ratification.

Read the whole thing. And, if you want a laugh, take a look at the ACLU’s twitter account dealing with the Paris Accord. The original tweets by the ACLU are embarrassingly funny, and so are the scathing responses.