The question was reverse global warming, not slow it down. So here's the reversal options: •Plant and bury. Grow plantlife where it hasn't been growing before

The question was reverse global warming, not slow it down. So here's the reversal options: •Plant and bury. Grow plantlife where it hasn't been growing before (oceans are one example, but tundras and deserts can also be used), and bury or otherwise control the output. •Weathering. The planet already has a system for removing CO2 from the air, it's just slow. Olivine rocks, along with limestone, trona, and pretty much anything with carbonates capable of becoming bicarbonates, will absorb CO2. •Injection. Assuming you can get CO2 in pure concentrated form, just need to pump it down to briny deposits that will absorb it. The bad news is almost nobody burning fossil fuels makes CO2 in pure concentrated form. The leading use of injected CO2 a) mines it already in concentrated form and b) uses it like fracking to push out more oil and gas, making its efficacy questionable.