- "My administration is committed to a leadership role on the issue of climate change. We recognize our responsibility and will meet it - at home, in our hemisphere, and in the world." – George W. Bush, 2001
- "While the Kyoto Protocol is a crucial step forward, that step is far too small. And as we consider how to go further still, there remains a frightening lack of leadership." – Kofi Annan, 2006
- "It is going to be very difficult to keep temperature increases down to between 2 and 3 degrees centigrade [3.6 - 5.4°F]. We should work very hard to do that." – Nicholas Stern, 2006
- "Halting global warming requires urgent, unprecedented international cooperation, but the needed actions are feasible and have additional benefits for human health, agriculture and the environment." – James E. Hansen, 2004