"We now need concrete measures in every country," Merkel told environment ministers and negotiators from 35 countries gathered in Berlin to lay the groundwork for an international climate conference in Durban, South Africa, starting November 28.
Germany and the European Union are pushing to agree on "a single and legally binding treaty" replacing the Kyoto Protocol, with industrialized nations taking the lead and emerging economies also contributing to reduce greenhouse gas emissions, Merkel said.
The 1997 treaty, named after the Japanese city, bound nearly 40 countries to specific emission reductions targets.
"Kyoto expires. That's why we have to make it clear what will be the way forward," Merkel told the representatives at the informal two-day meeting co-chaired by Germany and South Africa.
The conference in Durban is unlikely to yield a final agreement, but major steps in that direction have to be achieved, Merkel said.
"We have a giant task here," she added, referring to resistance from nations reaching from the U.S. to China to agree on ambitious binding climate targets.
Merkel stressed that emission reduction targets must not only be binding, but also verifiable. "As a matter of transparency ... it is necessary that someone can examine whether one sticks to the commitments," Merkel said.
The institution or the process overseeing the progress toward achieving the goals will also have to be agreed on, Merkel said.
Taking steps to fight climate change now comes with a cost and requires efforts, "but inaction would be yet more expensive," she said. "This is a challenge for humankind as a whole."
Scientists say climate change already has begun with more extreme weather events, more frequent heat waves and the melting of Arctic ice.
In the negotiations toward a post-Kyoto agreement, developing countries have insisted that the nearly 40 countries bound to specific reductions targets by the 1997 treaty renew and expand their commitments when they expire in 2012.
