Deutsch: Sequestrierung / Français: Sêquestration

Sequestration in the environmental context refers to the process of capturing and storing carbon dioxide (CO2) from the atmosphere to mitigate climate change. It involves removing CO2 emissions from the atmosphere and storing them in natural or artificial reservoirs, preventing their release back into the atmosphere. This helps to reduce the concentration of greenhouse gases and mitigate their impact on global warming. Sequestration plays a crucial role in carbon capture and storage (CCS) strategies and is considered an important approach in combating climate change.

Here are several examples of sequestration methods:

1. Terrestrial Sequestration:

   • Afforestation and Reforestation: Planting trees and restoring forests on degraded land helps sequester carbon through photosynthesis, as trees absorb CO2 and store carbon in their biomass and soil.
   • Agroforestry: Integrating trees into agricultural landscapes can enhance carbon sequestration while providing multiple benefits, such as improved soil health and biodiversity.
   • Soil Carbon Sequestration: Practices like conservation agriculture, cover cropping, and rotational grazing promote carbon sequestration in soils, enhancing their organic carbon content.

2. Oceanic Sequestration:

   • Ocean Fertilization: Adding nutrients to the ocean surface stimulates the growth of phytoplankton, which absorb CO2 during photosynthesis. When these organisms die, they sink to the ocean floor, effectively sequestering carbon.
   • Blue Carbon Ecosystems: Mangroves, seagrasses, and salt marshes are highly efficient at sequestering carbon in their biomass and sediments. Protecting and restoring these coastal ecosystems helps preserve their sequestration potential.

3. Geological Sequestration:

   • Carbon Capture and Storage (CCS): This involves capturing CO2 emissions from industrial sources like power plants and storing it underground in geological formations, such as depleted oil and gas fields or saline aquifers. CCS prevents CO2 from being released into the atmosphere.
   • Enhanced Oil Recovery (EOR): Some oil production operations inject CO2 into oil reservoirs to increase oil recovery. This process also has the potential to sequester a portion of the injected CO2 underground.

4. Bioenergy with Carbon Capture and Storage (BECCS):

   • BECCS involves the use of bioenergy, such as burning sustainably grown biomass, coupled with carbon capture and storage. The CO2 emitted during biomass combustion is captured and stored underground, resulting in negative emissions since the biomass absorbed CO2 during growth.

5. Direct Air Capture (DAC):

   • DAC technologies remove CO2 directly from the ambient air, typically using chemical sorbents or filters. The captured CO2 can be stored underground or utilized for various purposes, such as carbon-neutral synthetic fuels or industrial processes.

Other related approaches or concepts to sequestration include:

• Carbon Offset Projects: These projects support emissions reductions in one location to compensate for emissions produced elsewhere. For example, funding projects that protect forests or promote renewable energy can offset carbon emissions.
• Carbon Sink: A carbon sink refers to any process, activity, or reservoir that removes more CO2 from the atmosphere than it releases. Forests, oceans, and soils are considered natural carbon sinks.
• Carbon Neutrality: Achieving carbon neutrality means balancing the emissions of greenhouse gases with actions that remove or reduce an equivalent amount of emissions from the atmosphere.
• Carbon Footprint: The total amount of greenhouse gas emissions, primarily CO2, produced directly or indirectly by an individual, organization, or product.

Sequestration plays a vital role in mitigating climate change by reducing the concentration of greenhouse gases in the atmosphere. It encompasses various methods across terrestrial, oceanic, and geological domains, as well as innovative technologies like DAC and BECCS. These approaches contribute to the global effort of achieving carbon neutrality and promoting sustainable practices. Sequestration, along with emissions reduction and renewable energy adoption, is a crucial component of addressing the urgent challenge of climate change.

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