We already literally have cheap solar arrays and inexpensive electric vehicles (from ebikes to tractor trailors) that could replace the vast majority of GHG emissions. We have even have ruminate alternatives that are fairly convincing.
People don't want to use them: they're ugly, imperfect, foreign feeling.
We're at the point where we should only be worried about international plane travel, concrete, and shipping. Yet, we still act like the problem is technology... and we can't even build a train in CA because of politics.
It's worth remembering that "fusion = abundant power" is a guess about technology that hasn't been finished yet. Fusion power might turn out like solar panels (easier to build than expected) or like nuclear fission reactors (harder to build than expected).
