Question 55 from UPSC CSE 2021 - Current Affairs

Question

What is blue carbon?

IASCODEX · Accepted Answer

Correct Option: A. Carbon captured by oceans and coastal ecosystems

Strategy: Focus on the adjective 'blue', which in environmental contexts frequently refers to oceans or aquatic systems. Among options, only (a) directly connects blue with oceans and coastal ecosystems. Other options refer to land (forests/agriculture), fossil fuels, or atmospheric carbon, which are termed by different color-coded conventions (green, black, grey, etc.). Thus, (a) stands out logically and factually.

Key Info: **What is Blue Carbon?**
Blue carbon refers to carbon captured and stored by oceanic and coastal vegetative ecosystems. Key ecosystems include:
*   Mangroves
*   Salt marshes
*   Seagrass meadows

**Effectiveness and Storage**
These systems act as highly effective carbon sinks, removing atmospheric CO2 and sequestering it in both above-ground plant biomass and deep sediments. Blue carbon ecosystems store carbon at rates much higher per unit area compared to terrestrial forests, and their sediment beds can lock carbon for centuries or millennia.

**Climate Mitigation Importance**
Conservation and restoration of blue carbon habitats are prioritized in global climate mitigation strategies.

**Other 'Colored' Carbon Terms**
In contrast to blue carbon, other terms describe different carbon types:
*   **Green carbon:** Carbon stored in terrestrial plant systems (forests and soils).
*   **Black carbon:** Carbonaceous particles from incomplete combustion.
*   **Brown carbon:** Organic atmospheric particles.

**International Efforts and Examples**
International efforts like the Blue Carbon Initiative encourage the protection of these ecosystems due to their value for both climate regulation and coastal protection. Major blue carbon reservoirs include:
*   The Sundarbans mangrove forests
*   Coastal seagrass beds in the Mediterranean
*   Seagrass beds in the Great Barrier Reef region

IASCODEX · Answer

Option B: Carbon sequestered in forest biomass and agricultural soils

IASCODEX · Answer

Option C: Carbon contained in petroleum and natural gas

IASCODEX · Answer

Option D: Carbon present in atmosphere