Environmental groups have criticized the United States and Saudi Arabia for impeding progress at United Nations' climate negotiations in Argentina.
The conference concluded Saturday in Buenos Aires with the United States and the European Union agreeing to meet in May for what has been described as an "informal exchange of information" on climate change.
The agreement fell short of E.U. members' hopes of a series of "seminars" to discuss ways to address global warming after the Kyoto Protocol expires in 2012. The United States dismissed the idea as premature.
Environmental groups expressed their frustration over the conference's results, and accused the United States and Saudi Arabia of thwarting progress against global warming.
The Bush administration rejected the Kyoto Protocol in 2001, saying it would be too costly.
The Kyoto Protocol calls for industrialized countries to lower emissions produced by industry, automobiles, and power plants. The so-called greenhouse gases are often blamed for global warming.