UN climate negotiators gathered in Geneva were urged Sunday to show urgency and compromise in crafting a draft by next week for a global pact to be signed in December.

"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.

- 'Positive intentions' needed -

"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 (February 13) at 6:00 pm (1700 GMT) 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 $100 billion (88 billion euros) by 2020.

"As the primary bearers of the impacts of climate change, we have been asked to do so much and have made so many concessions in these negotiations throughout the years," said ambassador Nozipho Mxakato-Diseko.

"We... need to see all country parties bringing their positive intentions into this process."

A key disagreement is the issue of "differentiation" -- how to divide responsibility for curbing greenhouse gas emissions between rich and poor nations.

The participants also disagree on how to ensure, and measure, that the pledges collectively reach the 2 degrees C global target.

"We have to know how much is on the table and what more needs to be done," European negotiator Elina Bardram said Sunday.

"Like other parties we are concerned that the target set in Paris may fall short of what is required by science.... We will need to regularly set new targets that can respond to the new science and technological development."

Countries must submit carbon-cutting pledges in the months leading up to the Paris meeting.

The February 8-13 meeting is one of three special sessions added to this year's schedule of talks.