Coordinating shared sacrifice between 7 billion people was always unlikely to achieve much. There are good workarounds though. I think this is what will/should happen:

1. For now, we can cool Earth artificially. 1 gram of SO₂ in the stratosphere offsets the warming effect of 1 ton of CO₂. It's known to be safe and effective. This company is already doing it: https://makesunsets.com

2. Fossil fuels will be phased out over the next few decades, but CO₂ stays in the atmosphere for several centuries. The practical solution will probably have to be "carbon sequestration", where you capture CO₂ from the air and pump it underground where it stays forever. Such storage is mature tech in the natural gas industry, but the capturing CO₂ tech needs a lot of work.