The high-level segment of the UN climate talks opens this week in Poznań, Poland, from 11-12 December.
The negotiations will pave the way for next year's follow-up conference in Copenhagen, at which participants from 170 different countries are due to agree on a successor to the Kyoto Protocol.
"There is a clear recognition that the future agreement will not only be about reducing global emissions but also supporting necessary adaptation to climate change, particularly by the poorest and most vulnerable developing countries," Dimas said.
"Technology and finance will clearly be key to achieving both of these goals."
But while these 'building blocks' were already agreed upon a year ago in Bali, there is still some way to go before an agreement can be reached, Dimas warned. "What is still missing is what has become known as a 'shared vision' for the future agreement. It is in Poznań that this will come into focus for the first time."
According to the Greek commissioner, this shared vision should be about "more than just setting a long-term global emissions goal for 2050 and a medium-term goal for 2020," although he says these are important objectives.
For the EU, "it is also about creating a global understanding and establishing global cooperation to achieve low-carbon sustainable development that also delivers on the Millennium Development Goals" to reduce poverty, he said.
But the environment commissioner warned against expecting too much from the meeting. "Poznań was never going to be the occasion for major breakthroughs, since it only represents the halfway mark in a two-year process." What the meeting can do, he said, is build up some momentum ahead of next December's meeting in Copenhagen.
"By around the time of the first session of 2009, in March, we hope that the first negotiating texts will be on the table and all parties will need to engage from that point on." The UN work programme should also provide the opportunity to hold "an additional negotiating session, if required, in autumn 2009 on top of those already scheduled," he suggested.
EU summit outcome 'will not affect Poznań talks'
One difficulty with the Poznań talks is that the high-level segment on 11-12 December coincides with an EU summit in Brussels, which is due to decide upon the EU's own ambitious climate change and energy package.
But Dimas insisted this would not divert attention from the UN climate conference, saying progress could be made even in the absence of an EU deal on the climate package.
"It is of course only natural that there is great interest in the package," he said. "But it would be an exaggeration to say all eyes are on Brussels in the sense that Poznań can't make progress in the meantime. No-one is suggesting that."
He recalled that the EU had already agreed targets last year to reduce greenhouse gas emissions by at least 20% by 2020, regardless of the outcome of the EU summit this week. And the target would be increased to 30% if other developed countries commited to comparable reductions, he said, stressing: "This is the EU's unified position" and "it has not changed".
"The discussions on the package do not affect it in any way."
According to Dimas, topics where progress can be made regardless of an EU accord include "methodologies for measuring emission reductions from avoided deforestation, or political issues such as the shared vision of the future agreement".
