Enhanced weathering is a chemical approach to remove carbon dioxide involving land- or ocean-based techniques. One example of a land-based enhanced weathering technique is in-situ carbonation of silicates. Ultramafic rock, for example, has the potential to store from hundreds to thousands of years’ worth of CO₂ emissions, according to estimates.^[20][21] Ocean-based techniques involve alkalinity enhancement, such as grinding, dispersing, and dissolving olivine, limestone, silicates, or calcium hydroxide to address ocean acidification and CO₂ sequestration. Enhanced weathering is considered one of the least expensive geoengineering options. One example of a research project on the feasibility of enhanced weathering is the CarbFix project in Iceland.

Biochar is one of the proposed NET (Negative Emission Technologies): it captures the carbon from plants and keeps it chemically stable for centuries. Applications are in agriculture as animal feed or soil additive, as additive in building materials, or even in other products – such as electronics or plastics.

Direct air capture (DAC) is a process of capturing carbon dioxide (CO2) directly from the ambient air (as opposed to capturing from point sources, such as a cement factory or biomass power plant) and generating a concentrated stream of CO
2 for sequestration or utilisation. The technology is in an early stage, where its downside is the low economic viability at the moment. It could be facilitated through better economic utilisation of the CO2 or through political instrumnts, such as higher carbon prices.