 Nyorera kupfuurira kweiyi ndima - Muna Kukadzi 2009, Stern akati US yaizotora chinzvimbo chekutungamira mukugadzira chibvumirano chitsva chekushanduka kwemamiriro ekunze muCopenhagenmuna December 2009. Haana kupa chiratidzo chokuti U.S. yaizobvumidza Kyoto Protocol panguva ino. Mharidzo dzeUS Embassy dzakazoburitswa neWikiLeaks yakaratidza kuti US yakashandisa sei kuongorora, kutyisidzira uye kuvimbisa rubatsiro kuti iwane rutsigiro rweCopenhagen Accord, pasi payo chibvumirano chayo chekubvisa mweya ndiyo yakaderera pane imwe nyika inotungamira. 