"The losses that have been suffered in Haiti are nothing less than devastating, and responding to a disaster of this magnitude will require every element of our national capacity," Mr. Obama added. "For the sake of our citizens who are in Haiti, for the sake of the Haitian people who have suffered so much, and for the sake of our common humanity, we stand in solidarity with our neighbors to the south, knowing that but for the grace of God there we go."

We will not rest until we find all who were involved and hold them accountable. We will continue to use every element of our national power to disrupt, to dismantle and defeat the violent extremists who threaten us, whether they are from Afghanistan or Pakistan, Yemen or Somalia, or anywhere where they are plotting attacks against the U.S. homeland.

We come together here in Copenhagen because climate change poses a grave and growing danger to our people…. This is not fiction, this is science. Unchecked, climate change will pose unacceptable risks to our security, our economies, and our planet. This much we know.

I think our ability to take collective action is in doubt right now, and it hangs in the balance. I believe we can act boldly, and decisively, in the face of a common threat. That’s why I come here today – not to talk, but to act.

I would be remiss if I did not acknowledge the considerable controversy that your generous decision has generated. In part, this is because I am at the beginning, and not the end, of my labors on the world stage. Compared to some of the giants of history who have received this prize - Schweitzer and King; Marshall and Mandela - my accomplishments are slight.

We are at war, and I am responsible for the deployment of thousands of young Americans to battle in a distant land. Some will kill. Some will be killed. And so I come here with an acute sense of the cost of armed conflict - filled with difficult questions about the relationship between war and peace, and our effort to replace one with the other.

We must begin by acknowledging the hard truth: We will not eradicate violent conflict in our lifetimes. There will be times when nations – acting individually or in concert – will find the use of force not only necessary but morally justified.

I do not view it as a recognition of my own accomplishments, but rather as an affirmation of American leadership on behalf of aspirations held by people in all nations.

To be honest, I do not feel that I deserve to be in the company of so many of the transformative figures who've been honored by this prize.

I know that throughout history, the Nobel Peace Prize has not just been used to honor specific achievement; it's also been used as a means to give momentum to a set of causes. And that is why I will accept this award as a call to action - a call for all nations to confront the common challenges of the 21st century.