Has provisional application ever been used or proposed as a mechanism in the UNFCCC process?
While provisional application has never been used within the UNFCCC, there is precedent for Parties having made proposals requiring provisional application within the UNFCCC.
Australia
In early 1997, during the negotiation of the Kyoto Protocol, Australia (in the Ad hoc Group on the Berlin Mandate) proposed an article that would be inserted into the draft protocol. It provided for the provisional application of the Kyoto Protocol pending its entry into force.
The article was included in the framework compilation text (FCCC/AGBM/1997/2 and Add.1; dated 3 and 26 February 1997), the negotiating text (FCCC/AGBM/1997/3/Add.1; dated 22 April 1997) and the subsequent INF doc (FCCC/AGBM/1997/INF.1; dated 22 September 1997). It did not make it into the consolidated negotiating text, revised text under negotiation or the subsequent Kyoto CRP papers of draft protocol.
EU
Also in 1997, the Netherlands on behalf of the EU (from 1997) proposed an amendment to the Convention (to allow a protocol to be adopted by a three-fourths majority). The amendment contained language allowing for it to be applied provisionally pending its entry into force.