No liberal party in the West has any plans to actually do something substantial about climate change, that's precisely why all of them increase militarization of their borders and other anti-immigration measures. This isn't an exclusively Amerikan thing, it's also political consensus in the EU, Australia and so on. They know what they're doing to the planet, they know the bourgeois class will not allow them to stop it, so their answer is "let's just prepare to keep out the people whose home countries our emissions are about to destroy."