Question

Human activities in the recent past have caused the increased concentration of carbon dioxide in the atmosphere, but a lot of it does not remain in the lower atmosphere because of 

1. its escape into the outer stratosphere.

2. the photosynthesis by phytoplankton in the oceans.

3. the trapping of air in the polar ice caps.

Which of the statements given above is/are correct? 

1.    1 and 2
2.    2 only
3.    2 and 3
4.    3 only

Answer 1

Correct Answer - Option 2 :    2 only

The correct answer is 2 only.

• The photosynthesis by phytoplankton in the oceans is natural carbon Sequestration.
• What is Carbon Sequestration?
  • Carbon sequestration secures carbon dioxide to prevent it from entering the Earth’s atmosphere.
  • The idea is to stabilize carbon in solid and dissolved forms so that it doesn’t cause the atmosphere to warm.
  • The process shows tremendous promise for reducing the human “carbon footprint.”
• The trapping of carbon dioxide by polar ice caps is not known. Also, carbon dioxide does not escape into the stratosphere. Hence, statements 1 and 3 are incorrect.

• Types of Carbon Sequestration :
  • Biological carbon sequestration
    • It is the storage of carbon dioxide in vegetation such as grasslands or forests, as well as in soils and oceans.
    • Oceans absorb roughly 25 percent of carbon dioxide emitted from human activities annually. Hence, statement 2 is correct.
    • About 25 percent of global carbon emissions are captured by plant-rich landscapes such as forests, grasslands and rangelands.
    • When leaves and branches fall off plants or when plants die, the carbon stored either releases into the atmosphere or is transferred into the soil.
    • Wildfires and human activities like deforestation can contribute to the diminishment of forests as a carbon sink.
  • Geological carbon sequestration
    • It is the process of storing carbon dioxide in underground geologic formations or rocks.
    • Typically, carbon dioxide is captured from an industrial source, such as steel or cement production, or an energy-related source, such as a power plant or natural gas processing facility and injected into porous rocks for long-term storage.
  • Technological Carbon Sequestration
    • ​Scientists are exploring new ways to remove and store carbon from the atmosphere using innovative technologies.
    • Researchers are also starting to look beyond the removal of carbon dioxide and are now looking at more ways it can be used as a resource.
    • Graphene production: The use of carbon dioxide as a raw material to produce graphene, a technological material. Graphene is used to create screens for smartphones and other tech devices. Graphene production is limited to specific industries but is an example of how carbon dioxide can be used as a resource and a solution in reducing emissions from the atmosphere.
    • Direct air capture (DAC): A means by which to capture carbon directly from the air using advanced technology plants. However, this process is energy-intensive and expensive, ranging from $500-$800 per ton of carbon removed. While techniques such as direct air capture can be effective, they are still too costly to implement on a mass scale.
    • Engineered molecules: Scientists are engineering molecules that can change shape by creating new kinds of compounds capable of singling out and capturing carbon dioxide from the air. The engineered molecules act as a filter, only attracting the element it was engineered to seek.