OSLO  Thu Jan 22, 2015 5:00pm GMT

The United Nations asked governments on Thursday to submit plans to cut greenhouse gas emissions as the building blocks of a deal due in Paris in December to limit global warming, after scientists said 2014 was the hottest year on record.

Governments have agreed an informal deadline of March 31 to submit plans as the basis of the U.N. deal to slow climate change, which nearly all climate scientists say is mainly due to rising emissions of man-made greenhouse gases.

Christiana Figueres, head of the U.N. Climate Change Secretariat, said the meeting in Paris was a chance to get on track "towards a deep de-carbonisation of the global economy, achieving climate neutrality in the second half of the century".

The secretariat launched a website (here) to collect the national plans.

Climate neutrality means net zero emissions, or that any emissions from burning fossil fuels are offset by measures such as planting trees that soak up carbon dioxide as they grow.

Both NASA and the U.S. National Oceanic and Atmospheric Administration said last week that 2014 was the warmest year since records began in the late 19th century.

Alden Meyer, of the Union of Concerned Scientists, said record heat was "yet another indication of the severity of the climate problem" and should add urgency to government plans to be submitted to the United Nations.

He said the lower oil price might spur the use of fossil fuels but could also make it "more politically palatable" for some countries to cut fossil fuel subsidies. [O/R]

Top emitters China, the United States and the European Union have outlined plans for Paris but many details are not yet clear.