The conference also advanced a program to reduce deforestation and established a "loss and damage" mechanism to help island states and other vulnerable countries under threat from rising seas, extreme weather and other climate impacts.
The wording was vague enough to make developed countries feel comfortable that they weren't going to be held liable for climate catastrophes in the developing world.
U.S. and other rich countries also resisted demands to put down firm commitments on how they plan to fulfill a pledge to scale up climate financing to developing countries to $100 billion by 2020.
"In the nick of time, negotiators in Warsaw delivered just enough to keep things moving," said Jennifer Morgan, of the World Resources Institute, an environmental think tank.
"Country representatives now need to return home to make significant progress on their work plans and national offers that can become the backbone of a new climate agreement," she said.
The U.N. climate talks were launched two decades ago after scientists warned that humans were warming the planet by pumping CO2 and other heat-trapping gases into the atmosphere, primarily through the burning of fossil fuels.
Historically, most emissions have come from the industrialized nations, but the developing world is catching up fast, driven by rapid growth in major countries including China, India and Brazil.