Soils to Sequester Carbon

What is the issue?

The ability of soils to sequester carbon should be given a serious focus by policymakers in the context of climate change actions.

What is carbon sequestration?

It is the process by which carbon dioxide is removed from the Earth’s atmosphere and then stored in liquid or solid form.
It could involve both natural and artificial processes to remove and store carbon.
Significant carbon pools on earth are found in the earth’s crust, oceans, atmosphere and land-based ecosystems.
The prime purpose of artificially doing this is to mitigate or delay global warming and avoid extreme climate change.

What is the need for focussing on soils?

Agricultural Practices - After the changes undertaken as part of the Green Revolution, crop yields increased for several decades.
But parallelly there has also been a dramatic increase in the use of chemicals as pesticides, herbicides and fertilizers.
The resultant degraded soils are getting to be a prime reason for undermined agricultural yields in many places now.
Industrial changes to agriculture have led to a range of adverse effects including:
1. 1. loss of biodiversity
  2. elimination of beneficial microbes and insects
  3. reduction in yield
  4. contamination of water bodies and soils
  5. increasing toxicity, etc
Global Warming - Currently, the world is on a path to be about 3ºC warmer than pre-Industrial times.
This is despite adhering to 2015 Paris climate deal commitments.
Atmospheric concentrations of carbon dioxide have crossed limits and oceans are already turning acidic.
But, policies are largely focussed on reducing greenhouse gas (GHG) emissions from electricity sector, transport and industry.
The policy shortfalls call for a renewed focus in understanding how soils can serve as carbon sinks to address the increasing pressures.

How effective are soils as carbon sinks?

SOC - Soil organic carbon (SOC) comes from plants, animals, microbes, leaves and wood, mostly found in the first metre or so.
Soils contain around 2,300 Gt (1 gigatonne = 1 billion tonnes) of organic carbon, making this the largest terrestrial carbon pool.
Benefits - Increasing SOC through various methods can improve soil health.
It can contribute to agricultural yield, food security, water quality, and also reduce the need for chemicals.
It helps address carbon mitigation and also improve conditions of fresh water, biodiversity, land use and nitrogen use.
Moreover, carbon sequestration in soils has the potential to offset GHG emissions from fossil fuels by up to 15% annually.
Utilising this option would thus offer the breathing time before other technologies can help transiting to a zero-carbon lifestyle.

How is it achieved?

There are many conditions and processes that determine changes to SOC content.
These include temperature, rainfall, vegetation, soil management and land-use change.
Thus, increasing Soil Organic Carbon involves adopting sustainable agricultural practices to keep these factors in balance.
The approaches to increase SOC include:

What should the government do?

India does have a large number of successful sustainable agricultural practices.
The knowledge of farmers who have successfully experimented with these methods must be considered in research and policy.
State-level policy makers should identify the kinds of support needed by farmers with small holdings to transition from existing practices.
There is also a need for revising the existing fertiliser subsidy policy and promoting organic fertilizers.
The ability of soils to sequester carbon is thus a win-win strategy for farmers, people and for climate change.

Source: The Hindu