1. Are there technical requirements that would necessitate a delay between the adoption of a new Protocol under the UNFCCC and signature by heads of state or government?
2. Is it possible to open a Protocol for signature at a summit in one location and then leave the Protocol open for signature in New York for a year thereafter?
1. The successful outcome of negotiation will be the adoption and authentication of the agreed text. Signature of the agreed text has, as one of its functions, that of authentication. In addition, signature qualifies States to proceed to ratification, acceptance or approval and creates an obligation of good faith to refrain from acts calculated to frustrate the objects of the treaty.
In practical terms, whist an agreement may be reached at an international meeting, such as adoption of the final UNFCCC text in May 1992, there is still a requirement for the text to be revised by the secretariat to produce a copy of the agreement which can be authenticated. With the UNFCCC, the treaty was formally opened for signature (in Rio) in June 1992 a month after the text was adopted (in New York). The Kyoto Protocol took a few months longer.
Therefore, any agreement reached in Copenhagen would not be open to signature until the UNFCCC Secretariat was able to produce a copy which could be authenticated.
2. It is standard practice for UN treaties to be opened for signature in New York as this is the location of the UN Depository for all UN multilateral treaties. However this is not a strict rule. For example, the UNFCCC was adopted in New York (9 May 1992) but opened for signature in Rio de Janerio from 4 to 14 June 1992 and thereafter at UN Headquarters in New York from 20 June 1992 to 19 June 1993.
Therefore, in answer to the question, while it is possible to open a protocol for signature at a summit in one location and then leave it open for signature in New York thereafter, any new treaty or proto-col would not be able to be opened for signature in Copenhagen (as the place it would be adopted) as there is still the requirement of authentication before signature.
Additionally, once formally opened for signature, the treaty will remain open for signature for what-ever period the parties determine appropriate (e.g. the UNFCCC and Kyoto Protocol were both open for signature for 1 year), or indeed indefinitely. A treaty will ordinarily contain a provision that pro-vides the number of state parties to ratify the treaty before it enters into force (e.g. Art. 25 UNFCCC and Art. 23 Kyoto Protocol).