Text of President Barack Obama's remarks Friday at the U.N. climate summit in Copenhagen:

Good morning. It is an honor for me to join this distinguished group of leaders from nations around the world. We come here in Copenhagen because climate change poses a grave and growing danger to our people. All of you would not be here unless you _ like me _ were convinced that this danger is real. This is not fiction, it is science. Unchecked, climate change will pose unacceptable risks to our security, our economies, and our planet. This much we know.

The question, then, before us is no longer the nature of the challenge _ the question is our capacity to meet it. For while the reality of climate change is not in doubt, I have to be honest, as the world watches us today, 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. (Applause.)

Now, as the world's largest economy and as the world's second largest emitter, America bears our responsibility to address climate change, and we intend to meet that responsibility. That's why we've renewed our leadership within international climate change negotiations. That's why we've worked with other nations to phase out fossil fuel subsidies. That's why we've taken bold action at home _ by making historic investments in renewable energy; by putting our people to work increasing efficiency in our homes and buildings; and by pursuing comprehensive legislation to transform to a clean energy economy.

These mitigation actions are ambitious, and we are taking them not simply to meet global responsibilities. We are convinced, as some of you may be convinced, that changing the way we produce and use energy is essential to America's economic future _ that it will create millions of new jobs, power new industries, keep us competitive, and spark new innovation. We're convinced, for our own self-interest, that the way we use energy, changing it to a more efficient fashion, is essential to our national security, because it helps to reduce our dependence on foreign oil, and helps us deal with some of the dangers posed by climate change.