The informal high-level event hosted by Danish Prime Minister Lars Lokke Rasmussen on Friday gave a platform to leaders of major developed and emerging economies, offering them a chance to show their vision and make pledges for the world to join hands in a strong deal that will guide the international efforts in tackling climate change.
The speeches in a way were a war of different principles between the developed countries - represented by the United States and European Union - and the developing nations - represented by China, Brazil, India and others.
And there was no lack of grandstanding words.
India "has adopted and started to implement a major National Action Plan on Climate Change, relying upon our own resources," Indian Prime Minister Manmohan Singh told the assembly of 119 heads of state and governments.
Brazil President Luiz Incio Lula da Silva said his country was willing to make more sacrifices "to conserve and preserve the earth".
And US President Barack Obama had even more high-sounding words.
"As the world's largest economy and the world's second largest emitter, America bears our share of responsibility in addressing climate change, and we intend to meet that responsibility," US President Barack Obama said.
Obama declared that the US "will fulfill the commitments that we have made: cutting our emissions in the range of 17 percent by 2020, and by more than 80 percent by 2050 in line with final legislation."
Obama also reiterated the promise made by US Secretary of State Hillary Clinton on Thursday that the US would "engage in a global effort to mobilize $100 billion in financing by 2020.
But there is the "if," "and only if -- it is part of the broader accord", which stresses mitigation, transparency and financing.
But Obama made no mention of the previous UN conventions on climate change, which developing countries hold dear, noted Sudan negotiator Lumumba Di-Aping.
Throughout the negotiations during the past two weeks, the US placed a lot of pressure on emerging economies, especially China, about their responsibilities for future emissions and for making their low-carbon efforts transparent.
However, as Brazil President Luiz Incio Lula da Silva made clear during his speech, "people in the developed world all have three meals a day, but for people in many African, Latin American and Asian countries, three meals a day is still something in the future."
He said that developed countries "have the right to transparency, compliance". However, developing countries' experience with the existing international financial systems, such as the International Monetary Fund and World Bank, made it difficult for the developing nations to believe whether it would be carried out with "less intrusion and intervention".
However grandstanding Obama' speech was, representatives from non-governmental organizations expressed disappointment.
Martin Kaiser, Greenpeace International Political Advisor, pointed out that the rich countries "all miss the common but differentiated responsibilities principle in the morning talks.
"What Obama offered is very disappointing," Kaiser said. "He cannot leave Copenhagen without a bold reduction target. So far, the conference is headed toward a big failure."
In an official declaration by Greenpeacce, the organization said: "What Obama offered today is a take-it or leave-it deal. The world was waiting for the spirit of yes we can, but all we got was my way or the highway."
"The US's financial offer to other developing countries is based on the prerequisite of China's compromise in negotiation. No deal, no money," said Yu Jie, head of the Research Program of The Climate Group China office.
A Chinese official delegate who declined to have his name published also expressed disappointment at Obama's offer, saying the US emission reduction was totally incomparable to other developed countries which are currently obliged to binding-emission-reduction targets.
"It is only comparable to what the former US president Bush offered to mitigate climate change," he said.