Green Carbon is the carbon that has been stored in the biosphere. We call it 'green' because plants absorb carbon from the atmosphere through photosynthesis, which is dependent on the green chlorophyll pigment found in plant leaves. The carbon sequestered through photosynthesis and stored in natural forests is referred to as green carbon in this context. Natural forests are those that have not been disturbed by intensive human land-use activities such as commercial logging. In this article, we will discuss Green Carbon which will be helpful for UPSC exam preparation.

Role of Forest in Carbon Cycle and Climate Change

• Terrestrial ecosystems are responsible for approximately 25% of anthropogenic carbon dioxide emissions globally.
• Forests are a significant contributor to global carbon uptake and storage, and they are largely responsible for the consistency of the global carbon sink, with semiarid ecosystem response to precipitation and temperature accounting for interannual variability in carbon uptake.
• The dynamics of forest carbon source-sink and the total amount of carbon stored vary regionally and are heavily influenced by human land use, climate change, and disturbance.
• The relative importance of these drivers and the consequences of their interaction vary by region.
• The success of the strategies we use to leverage forest-based climate mitigation will be determined by a thorough understanding of the local ecological, social, and climate contexts.

Carbon Stocks in Major Terrestrial Ecosystem

Forests

• Forests have received the most attention in research on carbon sequestration and potential climate change mitigation by terrestrial ecosystems. This is primarily due to deforestation, which contributes to global CO2 emissions.
• Tropical rainforests alone cover approximately 9.4 million km2, an area nearly the size of China.
• These rainforests have an average organic carbon stock of 320 tonnes of carbon per hectare.

Peatlands

• Peatlands cover only 3% of the Earth's terrestrial area but have the second largest carbon stock of any terrestrial ecosystem, with an estimated average carbon stock of 1,450 t C/ha.
• As such, they represent a significant carbon sink and are gaining recognition for their significance and threat levels.
• Human activities threaten approximately 15% of global peatland area, either through drainage or burning, and the resulting CO2 emissions account for approximately 5% of global carbon emissions.
• The Global Peatlands Initiative coordinates activities related to peatland conservation on a global scale.

Grassland and Savannah

• In their natural state, grasslands and savannah cover nearly 25% of the Earth's terrestrial area, with an average carbon stock estimated at 150-200 t C/ha depending on climate and soil properties, with soil storing 80 percent of the carbon.
• Agriculture, animal grazing, fire and changes in climate conditions have the greatest impact on carbon stocks in grasslands and savannah.
• Grassland restoration could contribute up to 45 million tonnes of carbon sequestration per year, according to estimates.

Tundra

• Tundra ecosystems are mostly found in the northern hemisphere and cover nearly 10% of the Earth's land surface, with average carbon stocks ranging from 218 to 890 t C/ha.
• Tundra ecosystems are distinguished by their peat-forming vegetation, but they primarily store carbon stocks in their soils, particularly in permanently frozen layers of soil.
• They are the largest terrestrial organic carbon sink, along with boreal forests, containing at least 1,700 Gigatonnes of carbon.
• However, there is growing concern that tundra ecosystems will become a major source of carbon emissions as a result of climate change and increased human intervention, as permafrost layers release carbon when they melt or are disturbed and degraded.
• Existing anthropogenic threats are primarily caused by extractive industries (e.g., fossil fuel and mineral extraction), which may worsen in the future if the size and frequency of such activities increase.
• The distribution of carbon in tundra ecosystems is thought to be uneven, but this remains a mystery.
• There are currently no major international initiatives to conserve tundra ecosystems because halting and/or reversing permafrost thawing is impossible.
• However, when developing new activities, public and private sector actors can ensure that they plan effectively to avoid degrading these ecosystems.

Cropland

• Croplands, or agricultural lands, cover approximately 13% of the Earth's surface, with an average soil carbon stock ranging from 95 to 177 t C/ha.
• Currently, the majority of croplands are located in former forests and grasslands. Croplands' carbon sink function is highly variable and highly dependent on local climate and geological conditions, as well as management practises.
• Croplands are critical for global food security, but they generally reduce carbon stocks, especially if they come from converted natural or semi-natural habitats.

Conclusion

Green carbon is carbon that is stored in plants and soil in natural ecosystems and is an important component of the global carbon cycle. Currently, international rules are colorblind, so green carbon in natural forests is not recognised, resulting in unintended consequences such as ongoing deforestation and forest degradation, as well as the conversion of vast areas of land to industrial plantations.

FAQs

MCQs

1. What is the primary process through which plants absorb carbon dioxide from the atmosphere?

A) Respiration
B) Photosynthesis
C) Transpiration
D) Nitrogen Fixation

2. Which of the following ecosystems is primarily associated with Green Carbon?

A) Mangroves
B) Coral Reefs
C) Tropical Rainforests
D) Seagrasses

3. Which human activity is a major threat to Green Carbon storage?

A) Urbanization
B) Deforestation
C) Industrialization
D) Mining

4. What term is used to describe the carbon captured by oceanic and coastal ecosystems?

A) Green Carbon
B) Black Carbon
C) Blue Carbon
D) Brown Carbon

5. Which practice can enhance Green Carbon sequestration?

A) Monoculture Farming
B) Afforestation
C) Urban Expansion
D) Overgrazing

GS Mains Questions and Model Answers

Q1: Discuss the role of Green Carbon in mitigating climate change and the challenges associated with its conservation.

Answer: Green Carbon, stored in terrestrial ecosystems like forests, plays a pivotal role in mitigating climate change by absorbing atmospheric CO₂ through photosynthesis. This natural sequestration process helps reduce greenhouse gas concentrations, thereby limiting global warming. However, challenges such as deforestation, land-use changes, and forest degradation threaten these carbon sinks. Addressing these issues requires implementing sustainable forest management practices, enforcing conservation policies, and promoting reforestation and afforestation initiatives to enhance Green Carbon storage and combat climate change effectively.

Q2: Explain the differences between Green Carbon and Blue Carbon, and their respective roles in the global carbon cycle.

Answer: Green Carbon refers to the carbon stored in terrestrial ecosystems, particularly forests and vegetation, through the process of photosynthesis. Blue Carbon, on the other hand, is the carbon captured by oceanic and coastal ecosystems, such as mangroves, salt marshes, and seagrasses. Both play crucial roles in the global carbon cycle by sequestering atmospheric carbon, reducing greenhouse gas concentrations, and mitigating climate change. While Green Carbon focuses on terrestrial ecosystems, Blue Carbon emphasizes the importance of coastal and marine environments in carbon storage and climate regulation.

Q3: Assess the impact of human activities on Green Carbon reservoirs and suggest measures to protect and enhance these resources.

Answer: Human activities, such as deforestation, land-use changes, and industrialization, significantly impact Green Carbon reservoirs by releasing stored carbon back into the atmosphere, thereby contributing to climate change. To protect and enhance these resources, measures such as sustainable forest management, reforestation, afforestation, and conservation of existing forests are essential. Policies and incentives for community-based forest management, along with stricter regulations against deforestation, can further strengthen efforts to preserve and expand Green Carbon reservoirs, thus aiding in climate change mitigation.

Previous Year Questions on Green Carbon

1. UPSC CSE Prelims 2020:

Question: What is Green Carbon primarily associated with?

A) Coastal Ecosystems
B) Terrestrial Ecosystems
C) Industrial Emissions
D) Fossil Fuels

Answer: (B)

Explanation: Green Carbon is primarily associated with terrestrial ecosystems, such as forests and vegetation, which absorb and store carbon through photosynthesis.

2. UPSC CSE Mains 2019 (GS Paper 3):

Question: "Discuss the importance of Green Carbon in the context of global climate change and suggest measures to enhance its conservation."

Answer: Green Carbon, stored in terrestrial ecosystems like forests and vegetation, plays a critical role in mitigating global climate change by absorbing atmospheric CO₂. This process helps in reducing greenhouse gas concentrations, thereby limiting the effects of global warming. To enhance its conservation, measures such as reforestation, afforestation, sustainable forest management, and conservation policies are crucial. Protecting existing forests and promoting agroforestry practices can further bolster the capacity of terrestrial ecosystems to act as carbon sinks, thereby aiding in climate change mitigation efforts.