Ms Connie Hedegaard, the European Commissioner for Climate Action, has said the world has no choice but to complete the transition to low-carbon economy.
She noted that by 2050 there would be more than nine billion people on Earth and that the completion of the transition to a low-carbon global economy was important to accommodate this jump in population without stoking a dangerous climate change.
"That is what is at stake in the international negotiations on climate change, and that is why the forthcoming UN climate conference in Cancún is important," Ms Hedegaard said in a statement released by the European Union on Monday.
Ms Hedegaard said an ambitious and legally binding framework for global climate action was needed and that the European Union would be ready to agree this at the Cancún conference starting on November 29.
"Regrettably, a number of other major economies, including the US and China, are not," she said, adding that "Cancún will therefore not be the end of the road."
Ms Hedegaard said nonetheless the conference could still mark a significant step towards a legally binding global climate deal.
"It can - and must - deliver progress by agreeing a politically balanced package of decisions on a number of substantial issues that lead to immediate climate action on the ground.
"These decisions should capture the progress achieved in the international climate negotiations so far and lay down some major elements of the 'architecture' of the future global climate regime.
"They should build on the Kyoto Protocol and incorporate the political guidance of last December's Copenhagen Accord."
Ms Hedegaard said in recent preparatory meetings for Cancún she had seen a hunger for agreement along these lines, adding "with political will, the conference can translate this into a real step forward".
Ms Hedegaard said decisions were within reach on issues such as adaptation to climate change, the fight against deforestation, technology cooperation and governance rules for a new climate fund.
"For the EU, a balanced package must include progress on mitigating global greenhouse gas emissions.
"In particular, the emission reduction pledges that developed and developing countries have made under the Copenhagen Accord need to be brought into the United Nations framework."
Ms Hedegaard said "anchoring" the pledges in this way would provide a global forum to discuss uncertainties surrounding some of them and to consider ways to make them more ambitious over time.
"The current pledges are a start, but it is clear that they are not sufficient to keep global warming below 2°C, as recognised by the Copenhagen Accord."
Ms Hedegaard said there was the need to see progress in Cancún towards reforming and expanding the international carbon market in order to capture the huge potential for emission savings in the major emerging economies.
She said: "As Europe knows from our own Emissions Trading System, carbon market mechanisms reduce the cost of cutting emissions, can drive investment in innovative low-carbon technologies and can be important sources of funding for future climate action."
Ms Hedegaard said it was key that developed countries delivered on their pledges of "fast start" funding to help the developing world to fight climate change.
She said the EU had mobilised 2.2 billion Euros in fast start funding this year as part of its commitment to deliver 7.2 billion Euros over 2010-2012.
Ms Hedegaard said in Cancún the EU would give a comprehensive report of how it had implemented its pledge this year.
She also stressed that building trust also required greater transparency - transparency in how countries delivered on their emission pledges, and transparency in how developed countries would provide long-term funding to help the developing world to tackle climate change.
"That is why the EU is pressing for agreement in Cancún to draw up stronger monitoring, reporting and verification rules.
"A set of decisions in Cancún along these lines would constitute a significant intermediate step towards the robust and legally binding global agreement the world needs.
"An ambitious global framework will help to accelerate the low-carbon revolution that is under way, spurring 'greener' growth, creating new jobs and strengthening Europe's energy security."
She said achieving a politically balanced package would not be easy, but it was within reach.
However, failure, on the other hand, would raise the risk of the international climate negotiations losing momentum and relevance.