EU leaders are due to meet in Brussels on March 8-9 to agree a long-term energy strategy. As holder of the bloc's rotating six-month presidency, Merkel will lead the talks.

"If we continue on our current track, global greenhouse gas emissions will increase by 55 percent by 2030 compared to 1990," Merkel said. "We cannot close our eyes to the fact that this will have significant consequences."

But she said Germany could not make the same ambitious emissions pledges it made under the Kyoto Protocol.

In the collapse of East Germany's industrial base after reunification, Germany agreed under Kyoto to a 21 percent emissions cut between 1990 and 2012.

"Despite the fact that we represent only 20 percent of the (EU) population and about one-fourth of its emissions, the German government committed under Kyoto to 75 percent of the (EU) reduction because of German unification," she said. "In the next period this cannot be repeated."

Merkel is hoping an environmental agreement within the EU can set the stage for a broader international consensus on combating climate change at a Group of Eight summit she will host in June.

In addition to agreeing a cut in emissions, EU leaders are expected to agree a binding target on biofuels.

Divisions remain over whether to set a separate fixed goal for boosting renewable energy sources -- an issue Merkel did not touch on in her speech.