It was an honor system to reduce to the targets each country pledged to. That was one of several arguments against the deal...that it was not enforceable and that if only rich nations took the action required, like, reducing certain industries that supplied fossil fuels (coal and oil), subsidizing green energy products, carbon penalties and the other poorer nations did not (the assumption that economic growth would be more important), then it would hurt the economies of the richer nations while the poorer nations contributed nothing.
It was an honor system to reduce to the targets each country pledged to. That was one of several arguments against the deal...that it was not enforceable and that if only rich nations took the action required, like, reducing certain industries that supplied fossil fuels (coal and oil), subsidizing green energy products, carbon penalties and the other poorer nations did not (the assumption that economic growth would be more important), then it would hurt the economies of the richer nations while the poorer nations contributed nothing.