Only when there is a global agreement can EU nations fix a final figure for how much carbon each nation must cut. Those discussions on the EU's internal targets could set a base year for reductions other than 1990, Gabriel said.
U.N. figures show Europe is on track to meet its goal of slashing greenhouse gas emissions under the Kyoto scheme by 8 percent. But that figure was accepted by the EU when it only had 15 members, and its expansion eastward to embrace new members with less developed economies has complicated post-2012 plans.
Even old EU members like Finland, Spain and Denmark said they were concerned about the burden sharing.
Gabriel said the EU was facing a "historic decision" on climate change. He said Germany's parliament was ready to set the pace - with a cut of up to 40 percent.
"There will be some countries like Germany who will see a steeper reduction in greenhouse gases, and other countries, some of them no doubt in eastern Europe, that will have to achieve a lesser reduction in greenhouse gases because of the need to catch up economically," Gabriel said.
EU Environment Commissioner Stavros Dimas said EU nations had come a long way since last March, when leaders gave only vague direction to environment officials, telling them to look at a cut in global carbon dioxide emissions of between 15 and 30 percent.
"Not even the word 'target' was there," he said.
Netherlands bureau chief Arthur Max contributed to this report.
News stories provided by third parties are not edited by "Site Publication" staff. For suggestions and comments, please click the Contact link at the bottom of this page.