Todd Stern

[On setting ambitious Paris Agreement goals as an example for other countries] You never have impact unless you're walking the walk, not just talking the talk. The U.S. is going to have to produce a really ramped up NDC [nationally determined contribution] target for 2030.

[On replicating EU Green Deal programs globally] That's got to happen in the U.S., that's got to happen in China, that's got to happen in India, and Paris can provide some push but the Paris Agreement can't force countries to do that. [On a joint EU-U.S. carbon trade bubble] It will be enormously important for the EU and the U.S. to get synced up.

[On the impact of the U.S. adopting a clear stance on climate change internationally] It is the US driving the world in this direction that will be most important. If you have got the US, the EU, China working together you can expand to the whole world. It is not just about the US’s domestic emissions, but the US position as a world leader.

[On the U.S. withdrawal from the Paris Agreement] If Biden wins, then the fact that the withdrawal became final on November 4 really won’t matter. If Trump wins a second term, then it will have much more lasting impact.

[On the U.S. withdrawal from the Paris Agreement] The international community has seen the United States walk away twice.

Climate change is upon us with a vengeance and to contain it we need nothing less than to decarbonize the global economy in just three decades, starting now, and to deploy nature-based solutions in forestry and land use that can both reduce carbon emissions and absorb them naturally. We can do what’s required, but only if political will is mobilized at every level, from government leaders to business, civil society and ordinary citizens.

[On U.S. retrenchment from climate action] China, the EU and other leaders are going to be putting their minds to, 'OK, we have to live in a world without America. Maybe someday [they will] be back, but we really can’t wait.