@Steve 41oo,
First of all, the planet is not dying. This is an incredibly hyperbolic and human-centric notion.
Even if we accept the most dire and fanciful warnings, the worst that will happen is that the planet will no longer sustain certain manifestations of life (including humans). Not a pretty picture, but hardly the death of the Earth.
Secondly, if the planet is getting ready to shed itself of mammals, America alone cannot stop it and certainly Obama cannot.
I'm a big believer in American Exceptionalism, but even I don't think we, or our president, can keep the planet from dying.