"We expect from the United States to cooperate closer and not to continue having a negative attitude in international negotiations [on combatting climate change]," Dimas said.
"It is absolutely necessary that they move because otherwise other countries, especially the fast-developing countries, do not have any reason to move," he added.
Dimas also criticized Australia for lacking the political will to ratify the Kyoto Protocol.
Belgian Prime Minister Guy Verhofstadt called on the United States, China, and India to work harder to fight climate change. He said that "unpopular measures are unavoidable."
The UN-backed Intergovernmental Panel on Climate Change is working to finish a report on the impact of global warming on human life. It is expected to be released on April 6.
(AP, AFP, dpa)
View a photo gallery summarizing some key findings of the Stern report on the economic costs of global warming (epa)
THE STERN REPORT: In October, former World Bank chief economist Sir Nicholas Stern issued a 700-page report on the economic impact of global warming. The report, which was commissioned by the British government, estimates that climate change could cost between 5 and 20 percent of global GDP by the end of the century....(more)