Delegates at climate talks in Mexico appear to have reached a broad agreement that could eventually lead to significant cuts in greenhouse gases.
Earlier, there'd been pessimism that such a deal could be done.
Britain's Climate Secretary, Chris Huhne, had warned there was a real danger that the annual talks could become what he called a zombie process if there was not a successful outcome.
The BBC is reporting that a draft text under consideration could be a way of bridging the differences between nations that have seemed likely to scupper the talks.
Ministers and officials from 190 countries have been meeting in the resort of Cancun for the past two weeks to try to agree on a global framework for curbing greenhouse gas emissions.
Japan and Russia have been opposing further cuts under the Kyoto Protocol - a major demand of developing countries. There have also been divisions over a proposed fund to help poor nations deal with climate impacts.
The latest draft refers to a "second commitment period" of the Kyoto Protocol, implying an extension beyond the framework's first 2008-12 round.
The BBC's environment correspondent says the text is a step forward but the talks are still likely to go down to the wire. He says it's strong on acknowledging the scale of the problem but does not commit parties to new measures to curb emissions.