3. Direct air capture

Direct Air Capture is the process of capturing carbon dioxide directly from ambient air using solvents, filters or other methods.

Subsequent to being captured, the carbon dioxide would be stored with carbon capture and storage technologies to keep it permanently out of the atmosphere.

Finalists competing with direct air capture designs: Carbon Engineering, Canada Climeworks, Switzerland Coaway, US Global Thermostat, US Kilimanjaro Energy, US

4. Enhanced weathering

Enhanced weathering refers to geoengineering approaches that use the natural or artificially created minerals to remove carbon dioxide from the atmosphere. This is of 2 types

Terrestrial enhanced weathering: It is the spreading of crushed silicate minerals and other minerals on the land surface

Oceanic enhanced weatheringIt is the spreading of crushed silicate minerals and other minerals on the ocean surface. It utilizes from wave energy for natural spreading of sand particles, silicate minerals

But In this the higher pH of seawater may substantially decrease the rate of dissolution of atmospheric co2 with the silicates

Eg.Olivine a mineral used in enhanced weathering