US President Barack Obama has reached what he called a "meaningful" deal with China, India, Brazil and South Africa on climate change.
But the agreement struck on the last day of the Copenhagen conference does not set specific emission reductions and is not legally binding.
Below are reactions from key figures at the conference and non-governmental organisations.
BARACK OBAMA, US PRESIDENT
We're going to have to build on the momentum that we've established here in Copenhagen to ensure that international action to significantly reduce emissions is sustained and sufficient over time. We've come a long way but we have much further to go.
GORDON BROWN, UK PRIME MINISTER
We have made a start. I believe that what we need to follow up on quickly is ensuring a legally binding outcome.
JOSE MANUEL BARROSO, EU COMMISSION PRESIDENT
I will not hide my disappointment regarding the non-binding nature of the agreement here. In that respect the document falls far short of our expectations.
NICOLAS SARKOZY, FRENCH PRESIDENT
The text we have is not perfect... If we had no deal, that would mean that two countries as important as India and China would be freed from any type of contract... the United States, which is not in Kyoto, would be free of any type of contract. That's why a contract is absolutely vital.
XIE ZHENHUA, HEAD OF CHINA'S DELEGATION
The meeting has had a positive result, everyone should be happy. After negotiations both sides have managed to preserve their bottom line. For the Chinese this was our sovereignty and our national interest.
SERGIO SERRA, BRAZIL'S CLIMATE CHANGE AMBASSADOR
It's very disappointing, I would say, but it is not a failure... if we agree to meet again and deal with the issues that are still pending. We have a big job ahead to avoid climate change through effective emissions reduction targets and this was not done here.
LUMUMBA STANISLAUS DI-APING, HEAD OF G-77 GROUP
[The draft text] asks Africa to sign a suicide pact, an incineration pact in order to maintain the economic dominance of a few countries. It is a solution based on values, the very same values in our opinion that funnelled six million people in Europe into furnaces.
IAN FRY, TUVALU'S LEAD NEGOTIATOR
It looks like we are being offered 30 pieces of silver to betray our people and our future.
MOHAMED NASHEED, MALDIVES' PRESIDENT
Anything above 1.5 degrees, the Maldives and many small islands and low-lying islands would vanish. It is for this reason that we tried very hard during the course of the last two days to have 1.5 degrees in the document. I am so sorry that this was blatantly obstructed by big-emitting countries.
CLAUDIA SALERNO CALDERA, VENEZUELAN DELEGATE
I ask whether - under the eye of the UN secretary general - you are going to endorse this coup d'etat against the authority of the United Nations.
DESSIMA WILLIAMS, ASSOCIATION OF SMALL ISLAND STATES
We lost our vigorous commitment from other parties to [a temperature target of] 1.5C.
We were not able to secure a legally binding outcome. We were not able to secure mid-term targets, a peaking year and many other factors that AOSIS believes is crucial to our survival.
NNIMMO BASSEY, FRIENDS OF THE EARTH INTERNATIONAL
Copenhagen has been an abject failure. Justice has not been done. By delaying action, rich countries have condemned millions of the world's poorest people to hunger, suffering and loss of life as climate change accelerates. The blame for this disastrous outcome is squarely on the developed nations.
JOHN SAUVEN, GREENPEACE UK
The city of Copenhagen is a crime scene tonight, with the guilty men and women fleeing to the airport. There are no targets for carbon cuts and no agreement on a legally binding treaty. It seems there are too few politicians in this world capable of looking beyond the horizon of their own narrow self-interest, let alone caring much for the millions of people who are facing down the threat of climate change.
JOHN ASHE, CHAIR OF KYOTO PROTOCOL TALKS
Given where we started and the expectations for this conference, anything less than a legally binding and agreed outcome falls far short of the mark. On the the other hand... perhaps the bar was set too high and the fact that there's now a deal... perhaps gives us something to hang our hat on.