The UN's climate chief today called on the private sector to step up their efforts to support the "unprecedented, ambitious climate strategy" agreed by international negotiators at the Durban Summit last month.

Businesses must be better partners to governments, which have set themselves a deadline of finalising the details surrounding the Durban agreement before this year's summit in Doha, Qatar, Christiana Figueres told BusinessGreen.

"Businesses are reflecting the effort," she said, on the sidelines of the World Future Energy Summit in Abu Dhabi. "We already know that the trillion dollar in investment in renewable energy has occurred, that last year we hit the record of investment so we're definitely moving in that direction."

But she added that there was an obligation on businesses to further accelerate green investment.

"Can they do more? Should they do more? Absolutely," she said. "The challenge here is to hit a virtuous cycle of government defining the policy and direction and the private sector adding the impetus to get there. So both government and the private sector have to do more."

Earlier Figueres told reporters that the text governments agreed on at the Durban Summit had not been given the credit it deserved, after a number of NGOs warned that it was too vague and meant that a legally binding treaty was unlikely to come into effect until 2020, several years after the point at which climate scientists claim global greenhouse gas emissions have to peak.

However, Figueres defended the agreement, arguing that negotiators had finalised a deal to extend the Kyoto Protocol, the legal basis for emissions reduction schemes, created the $100bn Green Climate Fund to help poorer countries combat climate change, and set a timeframe for a new global emissions reduction deal to be agreed by 2015 and in place by 2020.

"There is no doubt in my mind that Durban [concluded with] a truly unprecedented, ambitious global climate strategy that is by far more encompassing and further reaching than any agreement in the history of the climate change convention," she said.

"It guaranteed continuation of the current legal system, cemented the broader mitigation efforts that are going to occur over the next eight years until 2020 and it identified the path toward the future system."

However, she admitted there was a considerable body of work ahead if negotiators are to iron out the details of the Durban agreement so that the new Kyoto period can begin on January 1 2013 as planned, just a couple of weeks after the Doha Summit is set to close.

Negotiators still need to finalise the length of the second commitment period and quantify emissions reduction targets for those countries signed up to an extension of Kyoto.

In addition, they will need to confirm the Green Climate Fund's oversight board – a point of contention for countries to date – and begin to source extra funding for climate mitigation efforts.

There is also growing pressure for diplomats to provide guidance on how the $100bn fund will be financed, particularly given proposals that fuel levies on shipping and aviation could be used.

Figueres conceded international efforts to curb emissions were not yet at the level demanded by scientists, but she insisted progress was being made within the existing political constraints to close the gap between ambition and reality.

"There's no doubt that there's a marked difference in the urgency that science defines and the pace with which governments are able to address the climate challenge," Figueres said. "However, what I see is that governments are not stepping away, that they are... actually increasing their ambition, have committed to a very specific process to do so, [and] have very stringent timelines for the different steps that they are going to take.

"So I think there is a growing awareness of the urgency, not yet a full step up to what science demands, but I do see them becoming more and more committed to be able to close the gap between the demands of science and what politics and economics allows.

"Doha will be a celebration conference because it will be able to approve all of the building work that is being done on infrastructure, on mitigation, on establishing the MRV [measurement, reporting and verification] process – all of the long, long homework list that has been set by governments. That will be reviewed in Doha and taken to the next step."