FOREIGN DESK | December 13, 2004, Monday Cheers, and Concern, for New Climate Pact By LARRY ROHTER AND ANDREW C. REVKIN; LARRY ROHTER REPORTED FROM BUENOS AIRES FOR THIS ARTICLE, AND ANDREW C. REVKIN FROM NEW YORK. (NYT) 1093 words Late Edition - Final , Section A , Page 13 , Column 1 ABSTRACT - Delegates from more than 190 countries gather in Buenos Aires, Argentina, to celebrate enactment of Kyoto Protocol, first treaty requiring cuts in greenhouse gases linked to global warming, and to look beyond 2012, when its terms expire; United States keeps to sidelines (M)