Did some digging.
Interestingly, the story might have been different if maybe, these concessions were granted. These concessions seem squarely aimed at placating the GOP base and donors that might have been sufficiently persuaded to stay in if Trump emerged looking like he wrested important concessions (that may not have been really that major). I wonder why the concessions weren't granted? The inside story sounds more interesting. Please note North Dakota Rep. Kevin Cramer's remarks in particular (and remember North Dakota is a major oil state).
I'm intrigued by Trump's language of wanting to re-negotiate and re-enter and deliberately putting the exit date on November 4, 2020 rather than cutting out the underlying treaty, which Pruitt advocated. I don't view it as mere lip service, given the intense internal debate within the Administration. He also has signed a 2009 newspaper ad calling climate serious and has attributed climate change to human activity (some, at least), right after his 2016 victory.
The story feels more complex than simply the GOP being reflexively anti-climate change. It may have come down to that they didn't feel their economic interests were being represented in this deal enough to continue.
Except the EU released a statement saying the Paris treaty will not be and is not able to be renegotiated.
It's just another Trump con
I don't see why they can't renegotiate, honestly. From what I gather the Paris accords are fairly toothless - developing economies basically get to keep using fossil fuels and developed ones agree not to, though there's really no enforcement mechanism and the effects on global warming are minimal at the macro level. Everyone sets their own arbitrary target for emissions. So what's wrong with just... changing the targets? The whole thing feels more to me like "look guys we did something!" than a concrete policy that will actually combat anthropogenic climate change
Besides, a commitment to lowered emissions from large states like CA and NY (paired with wind turbine innovation in Texas and expanded solar in other SW states) is already doing much for "greening" the US, along with the natural death of he coal industry. States giving grants to innovation in renewables would help, too. Thorium salt reactors could revolutionize nuke plants, etc
