People under the age of 50 may not remember how bad air pollution was until the 70s. I ran a 5 mile race in LA in '73 , and it felt like I'd smoked 2 packs. Later, the catalytic converter almost miraculously cleaned our air. The irony was that removing those particles from the air decreased solar reflectivity.

Now, cloud brightening and phytoplankton stimulation have been proposed as geoengineering solutions. Both may produce unintended consequences (too much phytoplankton = life choking algae blooms, cloud brightening = change in rainfall patterns). I believe much can be solved by increasing land-based plant growth (ie less-tillage, cover crops, less beef/dairy, returning more ag land to habitat). Many believe also that ocean currents play a big part (downward ocean transport decreasing heat and abetting "good" phytoplankton growth). Orbiting solar deflectors (possibly in the form of photovoltaic panels) have been discussed.

One or more of these things may be necessary, since 100% CO2/Methane removal may not be entirely possible, or by themselves a full solution.