"Keeping the show on the road" may be all governments can hope for at next week's UN climate talks, the UK admits.
Energy and Climate Secretary Chris Huhne said there was no chance of getting a legally binding deal at the summit in Cancun, Mexico.
The aim, he said, should be to get "within shouting distance".
Meanwhile, the World Meteorological Organization (WMO) released data showing that greenhouse gas levels continued their rise through 2009.
It follows publication of a scientific paper at the weekend suggesting that without new constraints, global carbon emissions will re-commence rising at 2-3% per year, following a brief lull caused by the recession.
And on Tuesday, the UN Environment Programme (Unep) said pledges that countries had made on constraining emissions were not enough to keep the global temperature rise within limits that most countries say they want - either 2C or 1.5C since pre-industrial times.
"We want to see progress [in Cancun] - we don't want to see a shambles that involves lots of name-calling," said Mr Huhne.
"If we don't get peaking of [global] emissions by 2020, the prospects for the people on the planet are looking pretty bleak, so we really do have to make progress on this."
Realistically, the government believes, progress could be made on issues such as reducing deforestation, financial pledges and bringing the unilateral carbon-cutting pledges that countries unveiled at Copenhagen into the UN framework so they can be properly analysed.
Western countries are equally keen to pursue the place that private finance and the business sector can play in leading the transition to a low-carbon global society.
But the Secretary of State was downbeat about how much progress was possible given the legacy of last year's Copenhagen summit, the domestic concerns of a few key countries including the US and China, and the differing demands of various negotiating blocs.
"We're clearly not expecting a final agreement at Cancun; but our objective is to ensure we re-invigorate the whole UN climate convention (UNFCCC) process and manage to get a new sense of momentum, with the ambition of reaching full agreement [at the summit] in South Africa next year," he said.
However, even that may not be possible, officials acknowledged, unless important countries can find a way to reconcile their domestic political problems with the demands of other nations.
The US Senate is extremely unlikely to ratify any UN climate deal, meaning that prospects of the world's second largest greenhouse gas emitter signing up to anything that other countries would consider legally binding is remote.
US officials - and their Canadian counterparts - are now talking openly about the possibility of a "Plan B" if Cancun does not move in the direction they want.
Among developing nations, China in particular has railed against demands from the West - and from Japan - that it must agree measures enabling its carbon-constraining performance to be monitored and verified.
The UK was encouraged by a recent Indian proposal to put international verification under the auspices of the UN climate convention.
But the US appears to be growing as an obstacle, with campaigners acknowledging privately that the balance of power in Congress is likely to become even less favourable to carbon-cutting legislation after the next round of elections in 2012.
Warming and wetting
The WMO data, meanwhile, confirms that atmospheric concentrations of the three gases principally responsible for the man-made component of the greenhouse effect - carbon dioxide, methane, and nitrous oxide - all rose during 2009.
The agency highlighted the rise in methane emissions, which it says is probably due to higher than average emissions from wetlands around the Arctic and in the tropics, both related to weather conditions.
Heightened methane emission from wetlands and permafrost has regularly been touted as a potential amplifying factor in climate change, with warmer weather stimulating their release and so producing further warming.
"Greenhouse gas concentrations have reached record levels despite the economic slowdown," observed WMO secretary-general Michel Jarraud. "Potential methane release from northern permafrost, and wetlands, under future climate change is of great concern, and is becoming a focus of intensive research and observations."