Scientists find how soil, a sink for GHGs, also contributes to climate change

Sub : Env

Sec : Climate change

Context:

A new groundbreaking study has revealed the critical role soil plays in contributing to global greenhouse gas (GHG) emissions, accounting for about 15% of global climate warming. The findings highlight the dual nature of soil as both a reservoir for carbon and a significant source of GHG emissions.

Key Findings:

Dominant Greenhouse Gases from Soil:
- Carbon Dioxide (CO2): Contributes 74% of soil-derived warming, mainly due to the loss of Soil Organic Carbon (SOC) from land-use changes.
- Nitrous Oxide (N2O): Accounts for 17%, primarily from inefficient nitrogen fertilization.
- Methane (CH4): Contributes 9%, mainly from rice paddies.
Historical Emissions:
- CO2 emissions peaked between 1800 and 1900 due to large-scale land-use changes, particularly in countries like Brazil and Argentina.
- These historical emissions still influence current atmospheric GHG levels.
Land-use Demand:
- By 2050, the United Nations Food and Agriculture Organization (FAO) estimates an additional 165-600 million hectares of land will be required for food production, intensifying soil emissions.

Challenges and Implications:

Soil emissions pose a significant barrier to achieving international climate goals, including limiting global warming to 1.5-2°C above pre-industrial levels.
The need to balance increased food production for a growing population with reduced soil-based emissions creates a “wicked problem.”

Recommendations for Mitigation:

Prevent Land-Use Changes: Avoid land-use changes for agriculture and biofuel production to preserve SOC and prevent further CO2 release.
Increase Nitrogen Fertilizer Efficiency: Optimize nitrogen use to curb nitrous oxide (N2O) emissions.
Reduce Methane from Rice Paddies: Implement water management and alternative farming practices to limit CH4 emissions.
Prevent Permafrost Thawing: Take actions to maintain permafrost integrity and avoid massive carbon and methane releases.
Soil Carbon Management: Develop strategies to enhance soil as a carbon sink while minimizing its GHG emissions.

Source: DTE