It's a complex problem with a lot of factors, but the GOP most definitely plays a role in a large part of the blame. Just look at the 1989 Geneva conference--the world came extremely close to signing a major international climate treaty that would collectively cap and eventually lower emissions.

The Bush Administration essentially single-handedly killed the treaty with a delegation of anthropogenic climate change deniers who believed it was an anti-American effort to thwart our country's economic growth.

Similar deal with the Paris Agreement, where the agreement was poised to lay the foundations of a future climate treaty. Then the Trump Administration announced that it plans on exiting the US from the agreement in 2020, and suddenly it becomes substantially more difficult for the agreement to induce a treaty at a later date when the world's largest economy isn't willing to participate.