Negotiators have been accused by charities and NGOs of not moving fast enough at interim talks in Germany.
Countries are working towards options to limit greenhouse gas emissions from 2020 ahead of a crunch December summit.
But the UN said progress had been made in streamlining the text of a new agreement.
The climate talks in Bonn are designed to pave the way towards the signing of a new deal in Paris at the end of the year that will shape the world's actions over climate change for decades to come.
On Wednesday, Christian Aid said there was a danger of ''sleepwalking into Paris''.
''There has been too much time spent fiddling around with the unimportant details of the text,'' said the charity's senior climate change adviser, Mohamed Adow.
''Negotiators have acted like schoolchildren colouring in their homework timetable and not getting round to any actual homework.''
He said negotiations must deliver ''a robust text soon otherwise they will cause further unacceptable delays and result in countries sleepwalking into Paris''.
Momentum is building towards the UN climate summit in Paris.
Key sticking points include finance to help developing countries adapt to climate change and agreeing on immediate and binding targets for carbon emissions.
But negotiating time is running out with only around 10 days' worth of negotiations remaining after the Bonn talks close.
On Wednesday, countries discussed new draft text for the agreement designed to boost climate action in the short term.
A network of NGOs known as the Climate Action Network said there were ''solid suggestions for delivering near-term action that will be up for decision in Paris''.
''Parties have moved forwards to consolidate the draft Paris text here in Bonn, this will help give ministers more clarity and enable them to provide political steer on crunch issues over the coming months,'' said Jake Schmidt of the Natural Resources Defense Council.
Delegates will return to Bonn in August and October for another two rounds of climate talks, before the summit in Paris at the end of the year.
Scientists say ambitious action is needed to avert the most severe impacts of climate change.
So far, more than 30 countries have pledged to limit emissions of greenhouse gases, with around 150 smaller countries yet to set goals.
Analysis suggests these do not go far enough to keep global warming below 2C.

President Nicos Anastasiades and Turkish Cypriot leader Mustafa Akinci met in Nicosia's neutral buffer zone.
UN envoy Espen Barth Eide said they "shared their vision for a united Cyprus".
Mr Akinci was elected last month. The Turkish-controlled north broke away in 1974 after a brief Greek-inspired coup.
Since a Turkish military invasion in 1974 the island has been effectively partitioned, with the northern third inhabited by Turkish Cypriots and the southern two-thirds by Greek Cypriots.
Peace negotiations stalled last October, when the Greek Cypriots walked out in protest at the presence of a Turkish ship prospecting for natural gas off the island's south coast.
Correspondents say there are hopes that Mr Akinci, a leftist moderate, can push forward the new round of negotiations.
"The talks took place in a very positive climate and I believe that working in similar fashion, we can hope for progress," Associated Press quoted Mr Anastasiades as saying after Friday's UN-brokered meeting.
In an initial move, Turkish Cypriot authorities agreed to no longer require Greek Cypriots to fill in visa forms at crossing points to northern Cyprus, UN envoy Mr Eide told reporters.
Compensation for those displaced by the conflict is expected to be one of the thorniest issues in the talks.
UN peacekeeping forces estimate that 165,000 Greek Cypriots fled or were expelled from the north, and 45,000 Turkish Cypriots from the south, although the parties to the conflict say the figures are higher.
The self-declared Turkish Republic of Northern Cyprus is diplomatically isolated, recognised only by Turkey.

Marchant, 20, has made 37 appearances for Quins since making his senior debut in May 2015, scoring 11 tries.
"I'm delighted to have re-signed with Harlequins," he said. "This is such a great club and I have loved my time here. It was an easy decision to stay."
Marchant had been due to tour Argentina with England last month but was ruled out with a toe injury.
International talks towards a new global climate deal are due to end on Thursday, amid concern that progress has been slow.
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The leaders of the divided Greek and Turkish communities in Cyprus have resumed peace talks amid a "climate of optimism", the UN mediator says.
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Harlequins centre Joe Marchant has signed a new and extended contract with the Premiership club.