Carbon Sequestration

Carbon sequestration refers to the process of capturing and storing carbon dioxide (CO₂) from the atmosphere to mitigate the effects of climate change. The main goal is to reduce the concentration of CO₂ in the atmosphere, which contributes to global warming and climate instability.

Types of Carbon Sequestration

There are two main types of carbon sequestration: biological and geological. Each method has its own set of benefits and challenges.

1. Biological carbon sequestration

Biological carbon sequestration refers to the natural process through which living organisms capture and store carbon. Biological carbon sequestration involves plants, soil, and oceans, which naturally absorb and store CO₂ through processes like photosynthesis and carbon uptake.

  i. Plants: One of the most common forms of biological carbon sequestration occurs through plants. Plants absorb CO₂ from the atmosphere during photosynthesis, using the carbon to grow and store it in their roots, trunks, and branches. This carbon can remain stored in the trees for decades.

ii. Soil: Another vital component of biological carbon sequestration is soil. The earth’s soil acts as a significant carbon sink, storing more carbon than all of the world’s plants and the atmosphere combined. Soil then acts as a long-term storage facility for this carbon, particularly when the soil is healthy and well-managed. Agricultural practices such as no-till farming, crop rotation, and organic farming techniques increase ability of soil to sequester carbon. When soil is disturbed through practices like tilling, much of the carbon stored in it is released back into the atmosphere, reducing its effectiveness as a carbon sink.

iii. Oceans: The world’s oceans also play a crucial role in carbon sequestration. Phytoplanktons absorb CO₂ from the atmosphere during photosynthesis. When these organisms die, they sink to the ocean floor, taking the carbon with them.

2. Geological carbon sequestration

Geological carbon sequestration is a more engineered approach to carbon capture, where CO₂ emissions are captured directly from industrial sources (like power plants or refineries) and stored underground in deep rock formations. These formations are typically located far beneath the Earth’s surface, where they can safely store CO₂ for thousands of years, preventing it from entering the atmosphere. This method of carbon sequestration involves three main steps:

i.   Capture: CO₂ is separated from industrial emissions before it enters the atmosphere. This is typically done using technologies like chemical solvents, membranes, or cryogenic cooling to isolate the CO₂ from other gases produced during combustion.

ii.  Transport: Once captured, the CO₂ is compressed and transported to storage sites. This is often done via pipelines, although transportation by ship or rail is also possible.

iii.  Storage: The CO₂ is injected deep into the Earth, typically into geological formations such as depleted oil or gas fields, deep saline aquifers, or unmineable coal seams. These formations have the necessary properties to securely store CO₂ without risk of leakage.

The Benefits of Carbon Sequestration

Carbon sequestration offers several environmental benefits by removing carbon dioxide from the atmosphere. Key benefits of carbon sequestration are:

i.      Climate mitigation: By reducing the amount of CO₂ in the atmosphere, carbon sequestration can help slow down global warming and its associated impacts.

ii.      Ecosystem restoration: Natural sequestration methods, like reforestation and soil regeneration, can restore degraded ecosystems and boost biodiversity.

iii.  Improved soil health: In agricultural practices, carbon sequestration can increase soil organic matter, leading to better water retention, nutrient availability, and reduced erosion. 

iv.   Enhanced crop yields: By improving soil quality, carbon sequestration can potentially lead to higher crop yields and greater agricultural productivity. 

v.   Economic opportunities: Carbon sequestration technologies can create jobs in industries like engineering, forestry, and renewable energy.

vi.   Improved air quality: Capturing CO₂ from industrial sources can also reduce other pollutants, improving air quality and public health.