Two weeks of contentious United Nations talks over climate change concluded on Sunday morning with an agreement by more than 190 nations to work toward a future treaty that would require all countries to reduce emissions that contribute to global warming.

The result, coming as the sun rose after nearly 72 hours of continuous wrangling, marked a tentative but important step toward the dismantling of a 20-year-old system that requires advanced industrialised nations to cut emissions while allowing developing countries including the economic powerhouses China, India and Brazil to escape binding commitments.

The deal on a future treaty was the most contested element of a package of agreements that emerged from the extended talks here. The delegates also agreed on the creation of a fund to help poor countries adapt to climate change, and to measures involving the preservation of tropical forests and the development of clean-energy technology.

The European Union had pushed hard for what it called a “road map” to a new, legally binding treaty against fierce resistance from China and India, whose delegates argued passionately against it. They said that mandatory cuts would slow their growth and condemn millions to poverty.

“Am I to write a blank check and sign away the livelihoods and sustainability of 1.2 billion Indians, without even knowing what the EU ‘road map' contains,” asked Environment Minister Jayanthi Natarajan. “Please do not hold us hostage.”

The deal renews the Kyoto Protocol, the fraying 1997 emissions agreement that sets different terms for advanced and developing countries, for several more years. But it also begins a process for replacing it with something that treats all nations equally. The expiration date of the protocol 2017 or 2020 and the terms of any agreement that replaces it will be negotiated at future sessions of the governing body, the U.N. Framework Convention on Climate Change.

The United States never signed the Kyoto treaty because it did not accept its division of labour between developed and developing countries. Todd D. Stern, the chief American climate negotiator, said he was hopeful that negotiations in coming years would produce a more equitable arrangement.

The conclusion of the meeting was marked by exhaustion and explosions of temper, and the result was muddled and unsatisfying to many. Observers and delegates said the actions taken at the meeting, while sufficient to keep the negotiating process alive, would not have a significant impact on climate change.

“While governments avoided disaster in Durban, they by no means responded adequately to the mounting threat of climate change,” said Alden Meyer, director of policy at the Union of Concerned Scientists. “The decisions adopted here fall well short of what is needed. — New York Times News Service