Except for the possibility of a Frankenstein dystopian geo-engineering of earth by creating clouds or similarly giant attempts to lower ocean surface temperature, humans cannot reduce net global average atmospheric CO2 concentration. Full stop. IMPOSSIBLE. CO2 that is removed or sequestered is replaced from the CO2 ocean surface reservoir which is about 1000 gigatonnes (1000 billion metric tons), that is, about 100 times larger than estimates of annual human CO2 emissions. IMPOSSIBLE for humans to reduce global temperature by reducing CO2. Stopping use of fossil fuels, or stopping eating meat, and other such schemes will not reduce net global CO2 concentration…ZERO effect. Human CO2 emissions have zero effect on earth’s temperature. A tree removes a lot of CO2 from the air, which is simultaneously replaced from the ocean’s huge CO2 reservoir.
Humans would have to try some monumental Frankenstein geo-engineering project designed to lower global temperature in order to reduce CO2 concentration. That would lead to disaster. You see, proponents of human-caused global warming have the science backwards. Temperature change causes CO2 change. CO2 concentration changes follow changes in ocean surface temperature (SST). Not the other way around. Air temperatures follow ocean surface temperature. Not the other way around.
When ocean surface is above about 25.6 C (~78 F) it emits CO2. Below 25.6 C ocean surface absorbs CO2. (There are local exceptions due to winds, salinity, alkalinity, bio-depleted and bio-generated CO2.) Increasing or decreasing area of ocean surface above or below 25.6 C increases or decreases respectively CO2 flux, that is, the directional velocity or rate of CO2 mass flowing through ocean surface area per unit time. On average, CO2 flux is about 90 gigatonnes per year emitted from ocean surface and about 90 gigatonnes absorbed per year. That is about 10 times more in both directions immediately diluting annual human CO2 emissions. The ratio of CO2 gas in air versus aqueous CO2 gas in ocean water for a given surface temperature is defined by Henry’s Law based on experiments documented by William Henry in 1803. The coefficient that determines the ratio of CO2 gas in air versus aqueous CO2 gas in ocean surface is determined by ocean surface temperature.