Carbon sequestration is the process of capturing gaseous atmospheric carbon dioxide and storing it in solid or liquid form. In IB ESS, it is studied at SL and HL in subtopic 2.3 Biogeochemical cycles as a flow that transfers carbon into a store.
How carbon sequestration works
Atmospheric is removed and placed in a carbon store where it remains for a period of time. If a system absorbs more carbon than it releases, it acts as a carbon sink; if it releases more than it absorbs, it becomes a carbon source.
| Type | Mechanism and example |
|---|---|
| Biological sequestration | Photosynthesis converts atmospheric into organic carbon stored in vegetation and soils. Forest restoration in Costa Rica has increased carbon storage while supporting biodiversity and ecotourism. |
| Ocean sequestration | Atmospheric dissolves in seawater and may be incorporated into marine biomass or sediments. However, increased dissolved also causes ocean acidification. |
| Geological sequestration | Technology captures from industrial emissions, compresses it, and injects it into underground geological formations. Norway's Sleipner project stores captured beneath the North Sea. |
Sequestration changes the carbon cycle by increasing flows from the atmosphere into terrestrial, oceanic, or geological stores. Greater storage can reduce atmospheric concentrations and help mitigate the enhanced greenhouse effect.
A common misconception is that carbon sequestration solves climate change by itself. It does not replace reducing fossil-fuel use: forests may burn, soils may be degraded, and engineered stores require monitoring to prevent leakage. Management also raises questions of cost, land ownership, and environmental justice, particularly where local or Indigenous communities are affected by forest-protection policies.
Exam technique
For an explain question, identify the carbon store and describe the flow moving carbon into it. For an evaluate question, balance climate benefits against permanence, capacity, cost, ecological impacts, and stakeholder perspectives, then reach a supported conclusion using a named example.
