"I ask you to work with efficiency and a sense of compromise," Manuel Pulgar-Vidal, Peru's environment minister and president of the negotiations told the opening session of the six-day talks.
Pointing to scientific warnings of a dangerous Earth-warming trend, he appealed to national representatives to "work with an even higher sense of urgency".
"This is not a competition among us. We are just one team for one planet."
Negotiations resumed for the first time since an annual ministerial-level meeting in Lima last December yielded a sprawling 37-page blueprint for the agreement that countries had in 2011 agreed to finalise by the end of this year.
To be inked in the French capital, the pact must enter into force by 2020 to further the UN goal of limiting global warming to two degrees Celsius (3.6 degrees Fahrenheit) over pre-Industrial Revolution levels.
Scientists warn that on current greenhouse gas emission trends, Earth is on track for double that -- a recipe for catastrophic droughts, storms, floods and rising seas.
"If the climate is unstable, world security is unstable – everything from immigration to conflict over resources, whether it be oil or water," French foreign minister Laurent Fabius said on the sideline of the talks.
On Monday, the World Meteorological Organisation said 2014 was the hottest year on record -- part of a "warming trend" set to continue.
But the 195 nations gathered under the UN banner remain at odds over the way forward, split broadly on rich-developing country lines, and the Lima document is stuffed with options that reflect conflicting interests and demands on many
fundamental points.
The goal of Geneva is to trim the document down to a workable draft for an official "negotiating text" to guide the process through to December.
Procedure requires that an official draft text must be submitted by the end of May this year -- six months before the next Conference of Parties in Paris that will adopt the final version.
"This session in Geneva is the only session planned before May 2015," the meeting's co-chairman Daniel Reifsnyder of the United States told delegates.
"The objective is to deliver... on Friday  at 6:00 pm the negotiating text of the Paris climate agreement," he said.
South Africa, on behalf of a broad group of developing and poor nations, called for a show of good faith -- including for rich countries to show how they intend to keep a promise to scale climate assistance up to USD 100 billion (88 billion
euros) by 2020.

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