Mr. Obama expressed support on Sunday for a proposal from Prime Minister Lars Lokke Rasmussen of Denmark to pursue a two-step process at the Copenhagen conference.

The summit comes two months ahead of a key meeting in the Danish capital, Copenhagen, aimed at approving a global treaty on cutting carbon emissions.

While Copenhagen is not expected to produce a deal that's ready for participating countries to ratify, Pasztor said the summit in the Danish capital still can produce a detailed framework.