The review will be led by Robbert H. Dijkgraaf, a Dutch physicist and mathematician who is co-chairman of the InterAcademy Council. The study group will be financed by the United Nations but will operate wholly independently, Mr. Dijkgraaf said at a briefing at the United Nations.

He said he was not certain how many members would serve in the group, but said they would represent a variety of scientific disciplines. He expects to complete the review by the end of August, before the I.P.C.C. officially begins work on its next scientific assessment report, which is to be completed in 2014.

He said that the group intended to look forward rather than backward and would make recommendations on how to assure the accuracy of the next assessment and on setting standards for the types of publications that can properly be cited.