acid rain: stop emitting sulfur, it'll wash out of the atmosphere within years, forests will recover in decades ozone layer: stop emitting CFCs, they'll decomp

acid rain: stop emitting sulfur, it'll wash out of the atmosphere within years, forests will recover in decades ozone layer: stop emitting CFCs, they'll decompose over decades and ozone concentrations will rise again climate change: just stop emitting carbon and... no wait, we're still locked into centuries of rising ocean levels and temperatures even if we lowered everything to zero right now. It would take actively extracting CO2 from the atmosphere at very very large scale to reverse the effects.