For now nothing will happen. What they're proposing is similar to the Paris Agreement for climate change, which almost 200 countries signed (and the US notably withdrew from recently) after activists convinced everybody that the human species is doomed unless we take immediate action. Regulating AI globally like that will take years of negotiations on the international political stage. Also, the current US government is strongly opposed to regulating and slowing down AI R&D, it's very unlikely they would sign any policies that suggest to do so.
And even if a deal similar to the Paris Agreement would be signed for AI, it's still up to local governments and companies to actually follow it, which is yet another story.
