Obama: I came here to act - "Our ability to take collective action is in doubt"

As the fifth speaker, President Barack Obama took the floor in the plenary. He stressed that he did not come to talk, but to act.

Being the world largest economy and second largest emitter of greenhouse gases, America has a responsibility, he said, and added that America would continue to move toward a green economy – "but we will be stronger if we act together," he said.

He told the heads of state and governments that it is imperative with a "mechanism to review whether we are keeping our commitments, and to exchange this information in a transparent manner." Without such accountability, any agreement would be "empty words on a page".

"Mitigation. Transparency. And financing. It is a clear formula - one that embraces the principle of common but differentiated responses and respective capabilities. And it adds up to a significant accord – one that takes us further than we have ever gone before as an international community", Obama said in his address.

Finally he urged world leaders to "choose action over inaction; the future over the past - with courage and faith, let us meet our responsibility to our people and to the future of our planet".