My closet tinfoil hat conspiracy theory of choice is that the powers that be in the US all accept climate change, but some think the US will be hurt less than other emerging superpowers by it and thus be able to leverage it into continued global hegemony.
I have no evidence to back up this theory. They are probably just stupid.
It will go faster, so you're technically correct
Current Paris accord climate change policy is essentially a wealth transfer - rich western countries pay into a fund, that is currently slotted at $10 billion dollars raised (total) but the expectation is that the fund would grow to $100 billion, ANNUAL contributions within the next 30 years. Western countries pay in, poorer countries get funds distributed from the fund to ?? do something about climate change in their country ?? Historically, wealth distributions like this have simply gone to line the pockets of the corrupt, and not truly helped the people in the countries affected.
The problem is simply this: Western countries climate impact is really based on the things we buy now, not pollutants we create in our own countries. Sure, driving cars in America or garbage recycling in Europe may be a minor problem, but it is insignificant compared to the steel created in India and China for goods sold in USA/Europe, the electronics created in China sold worldwide with minerals mined from Africa, the meat, chicken, and vegetable industries in South America we are the consumers of, etc.
That itself is also a trivial problem compared to the fact that there are ~600m "middle class" westerners, and around 500m currently in Asia which can grow to over 1.5b over the next 20 years. Those people want their own cars, to eat quality meat every day, to own lots of electronics, to take vacations to far off places, and to consume and all those things are adding to environmental stresses. And who are we to say "well... we got in while everything was good, but you can't have any of that stuff cuz its bad for the planet, ok?"
Even China is getting into the act, beyond being the worlds biggest polluter at home, they are investing heavily in coal power plants in other parts of the world (Africa, Asia, South America) to move their businesses elsewhere, because their own people don't want more pollution at home. Out of the ~1600 coal plants expected to be built worldwide in the next 10 years (43% expansion, virtually none built in the USA) about 40% are Chinese funded, 700 in China, and the rest in other countries.
https://www.nytimes.com/2017/07/01/climate/china-energy-companies-coal-plants-climate-change.html
At this point the grim reality is that either we are going to have to come up with new technological solutions to the global warming problem - ways to essentially take carbon out of the atmosphere and shoot it into the sun, inside the earth, domes to protect us from the higher temperatures, colony missions to new stars, whatever - or a few billion people have to die to relieve global demand for goods and services.
Previous wars were fought over idealogy, the next big war will likely be fought over water.
Who knows though, Elon Musk or a 11 year old kid could invent a new stable infinite energy battery that rapidly replaces all our power grids. Vat grown meat could become a thing quickly. People were absolutely sure in the 70s food was going to grow too scarce to feed more than 2 billion people, and then GMOs and fertilizers let us hit 7 billion populations.