Mandate nukes or renewables globally for electricity generation in 20 years. This with the more widespread adoption of electric cars will reduce greenhouse gases by 50%. Right now because of the high levels of CO2 half of the CO2 we generate is absorbed by the oceans. If we reduce CO2 production by 50% all of the CO2 we produce will be absorbed by the oceans and the atmospheric CO2 levels will stabilize.
Another advantage of the above solution is it frees up more natural gas for use in cars, space heating and industrial processes, improves our energy security and would reduce the price of fossil fuels in general