Ministers and other high-level officials from 45 countries are set to gather in Paris on Monday, in a bid to breathe fresh life into climate talks that have been bogged down with technical details and political squabbling.
It comes just four months ahead of a UN conference in the French capital tasked with producing a historic climate pact.
US scientists claim new figures show 2014 was a record year rises in sea levels, land temperatures, and the greenhouse gases that drive dangerous global warming.
But overwhelming consensus on the urgency of the problem has not translated into significant global progress to prevent the planet from overheating.
"The negotiations have not, strictly speaking, begun yet," Laurence Tubiana, France's chief climate negotiator, told journalists this week.
Ministers meeting on Monday and Tuesday "have to take ownership of the content of the negotiation, otherwise their negotiators will not really be able to engage on the key political issues," she said.
The political discussions will be followed in Bonn at the end of August with technical negotiations on the content of a draft agreement, with another ministers' gathering slated for September.
The 32 foreign and environment ministers and 13 senior negotiators in Paris, working under the guidance of France's chief diplomat Laurent Fabius, have their work cut out for them.
A draft agreement emerging from earlier rounds is little more than an exhaustive laundry list of problems and options, and is too unwieldy, Tubiana said.
The 195-nation UN Framework Convention on Climate Change (UNFCCC) has embraced a goal of limiting average global warming to two degrees Celsius over pre-Industrial Revolution levels.
Scientists say disastrous climate change can be avoided at this threshold, but warn the planet is on target for double that, or more.
Small island nations and poor countries in Africa and Asia, which will be hardest hit by climate-change effects, say 2C is not ambitious enough, and favour a 1.5C target.