Carbon-Dioxide Removal

Process

Examples

Traditional

process

• Afforestation
• Reforestation
• Agricultural practices that sequester carbon in soils (carbon farming)

Technological process

• Bioenergy with Carbon Capture and Storage (BECCS)
• Direct Air Carbon Capture and Storage (DACCS)
• Enhanced rock weathering

CDR method

About

Challenges

Afforestation/ Reforestation

• Converts abandoned or degraded agricultural lands into forests.
• Additional trees can sequester more carbon dioxide from the atmosphere.

• Increases the competition for land.
• May limit the options for food production and biodiversity conservation.

Biochar

• A substance produced by burning organic waste from agricultural lands and forests in a controlled process called pyrolysis.
• Improve soil quality, which in turn improves soil fertility, productivity and crop yield.

• Health and environmental impacts of particulate matter produced during pyrolysis.
• Sourcing sustainable biomass at a scale.

BECCS

• Combines energy production, biological carbon removal and geological storage.
• Uses biomass in combustion to generate energy, then captures the emitted carbon for geological injection.

• Can create competition for land use with food production, placing pressure on food security.
• Can increase the use of fertilisers.

DACCS

• Extracts CO2 directly from the atmosphere, and is permanently stored in geological formation or used for other application.

• Accelerates fossil fuel extraction activities, potential CO₂ leakage from storage sites

Enhanced rock weathering

• Involves pulverising silicate rocks to bypass the conventionally slow weathering action.

• Energy intensive process and generates emissions.

Ocean alkalinity enhancement

• A chemical removal method that involves adding alkaline substances to seawater to accelerate the natural sink.

• Potential for increased greenhouse gas emissions and can release by-products like trace metals.