Marathon talks over the weekend look likely to produce a deal at the World Summit for Sustainable Development this week, even if many environment and development activists will be unhappy with some of the compromises.
"We are very much in the last 100 metres," the Minister for the Environment, Mr Cullen, told Irish journalists last night. However, he conceded that a number of outstanding issues remain to be resolved, notably the setting of minimum targets for renewable energy over the coming decade or so.
As a result of officials "working round the clock" to deal with issues in dispute between the US and its allies at the summit on the one hand, and the EU and developing countries on the other, he said the pace of change had been significant. "We are close to the wire on a number of issues," he added.
It is expected that the South African President, Mr Thabo Mbeki, will present a draft of the summit's political declaration today, but most of the attention will focus on the precise content of what has become known as the Johannesburg Plan of Implementation.
"The devil is in the detail," one observer said.
World leaders have begun arriving here for this final phase of the summit. The US Secretary of State, Mr Colin Powell, is due tomorrow, as well as most EU heads of government, including the Taoiseach, Mr Ahern. The British Prime Minister, Mr Tony Blair, is flying in today from Mozambique.
Although major progress has been made on the contentious issue of corporate accountability, with the US delegation seeking clearance from the White House to go along with some form of international regulation, environment and development groups seized on the text dealing with trade as a sell-out.
It was never likely that the summit would seek to subvert the World Trade Organisation, but critics of the draft text in this area - agreed between the US, the EU and some of the developing countries - say its effect would be to copperfasten the current dominance of trade over environmental considerations.
Mr Cullen insisted, however, that the emerging deal had its positive aspects - such as a pledge to phase out the use of toxic chemicals by 2020 and the inclusion of specific references to the Kyoto protocol on climate change, which the US delegation had sought to expunge from the negotiating text.
"The EU has been pushing the \ agenda on all fronts and trying to bring others with us," he said.
But he stressed that "nothing is agreed until everything is agreed".
He also revealed that delegations at the summit had "signed off" on the issue of subsidies for agriculture at 3 a.m. yesterday morning. Moves had been made within the EU to agree to more forthright language in committing itself to negotiate phasing out such subsidies, which amount to a global total of $350 million.
The agreed text is "balanced", the Minister said, adding that he had not come to Johannesburg to renegotiate the Common Agricultural Policy. "I think we got a very good deal from the G77 [group of developing countries] and the US, which recognises that the \ Doha process is already in place".
The issue of setting targets for renewable energy is one of the most contentious here. Brazil has proposed that renewables such as solar and wind power should account for 10 per cent of global energy by 2010. The US is strongly opposed to this, while the EU would be prepared to settle for softer targets.
Any watering down of commitments is being monitored closely by the environment and development groups. Using language such as "moving towards" and "if possible" in relation to targets and timetables is also seen by the EU as offering so many "get-out clauses" that the agreement would be rendered meaningless.
Discussions were still continuing on the establishment of a World Solidarity Fund to aid sustainable development, although it is unclear how this would fit in with existing financial instruments under the UN's umbrella - notably the Global Environmental Facility, established at the first Earth summit in 1992.
