Understanding the nexus between soil degradation and Climate Change
Dr. Sanjeev Narrainen
The UN Intergovernmental Panel on Climate Change 2019 Report revealed that our soil is degrading at an alarming rate, with a significant loss of macro and micro nutrients.
Contemporary societies live on a cultivated planet where agriculture covers approximately 38% of the land surface (Borrelli et al., 2020). Humans strongly depend on the capacity of soils to sustain agricultural production and livestock, which contributes more than 95% of global food production (FAO, 2015). Soil is the biggest terrestrial carbon sink (IUCN, 2015).
The world’s soils store more carbon that the planet’s biomass and atmosphere combined.
This includes soil organic carbon, which is essentially biodiversity, microbes, fungi, and invertebrates, as well as root matter and decomposing vegetation. Organic matter is one of the significant constituents of soils. It frames soil structure and stability, water and oxygen holding capacity, and nutrient storage, hence it furnishes a home ground for numerous soil micro fauna and flora. The microbes, insects and other organisms in soils are essential for soil health. Unfortunately, with changing climate, our soil conditions are changing. The combined effect of climate change and land mismanagement has resulted in an increasingly degraded soil. This leaves the soil with a reduced ability to support crops, livestock, and wildlife.
Soil degradation is essentially a reduction/ loss of the biological or economic productivity and complexity of land. Soil degradation encompasses change in the chemical, physical and biological properties of the soil. Such a change in soil properties alter and reduce the soil ability to sustain a peculiar quality and quantity of plant growth. Soil degradation manifests itself in many ways: land abandonment, extinction of species, loss of soil and soil health, reduction of rangelands and fresh water, and deforestation. The health of our soil is crucial to storing carbon. Soil condition facilitates many of the processes that affect climate from plant growth to carbon dioxide intake.
Key facts and figures about Soil degradation
- Soil degradation through human activities is undermining the well-being of at least 3.2 billion people.
- It encourages species extinction
- By 2050, soil degradation and climate change will reduce crop yields by an average of 10% globally, and up to 50% in certain regions.
- Soil degradation increases the number of people exposed to hazardous air, water and land pollution, particularly in developing countries.
- Developing national strategies for soil conservation.
- Sustainable land management can be accelerated through policy and financial instruments
Why Soil Matters?
The footprint that human activities have left on the world’s soils are tangible (Montanarella, 2015). The associated losses of nutrients, such as nitrogen and phosphorus, and organic carbon (Quinto et al., 2010) have shown compromising long-term effects on the local ability of certain soils to meet agricultural production and ecosystem service demands (Robinson et al., 2017). With increased erosion there is a consequent depletion of nutrients as organic matter in the soil leading to nutrient deficiency. Micronutrients such as boron and zinc are essentials in small quantities for health benefits. It has been observed that in certain areas with soil degradation, people are deficient in micronutrients, vitamin A, iron, zinc, and in particular boron.
Soil organic carbon contributes to the fertility of the soil and to its capacity to hold water, and therefore to a large extent determines the capacity of the soil to produce food and to support other biodiversity. It represents great challenges for sustainable development, biodiversity conservation, and above all mitigation and adapting to climate change (Robinson et al., 2017).
When soil is degraded, soil carbon can be released into the atmosphere, along with nitrous oxide, making land degradation one of the biggest contributors to climate change. An estimated two-thirds of all terrestrial carbon stores from soils and vegetation have been lost since the 19th century through soil degradation.
Climate Change
Anthropogenic climate change is recognized as one of the major factors contributing to land degradation. Soil degradation worsens climate change and undermines well-being of billions of people. The UN Intergovernmental Panel on Climate Change Report (2019) revealed that our soil is degrading at an alarming rate.
Soil degradation is a major contributor to climate change, and climate change is foreseen as a leading driver of biodiversity loss.
There is overwhelming evidence which points the consequences of climate change in land degradation. For instance, risk of soil erosion in South Korea is rapidly increasing due to the variability of rainfall in the recent past (Kang et al., 2021).
Climate change has severe consequences that can directly affect the quality of soil, including:
- Acidification
- Impact on nutrient levels
- Acid sulfate
- Changes to soil structure.
Consequences of soil degradation
Mismanagement of land significantly limits the ability to rebuild the soil’s ecosystem. Soil quality and function are being lost due to unsustainable management practices. The consequence is the inability of the biosphere to support the production of food and support all the processes and services that we get from healthy agricultural and natural ecosystems. Conversely, degraded soils will lead to poor plant growth and reduced carbon dioxide uptake from the atmosphere.
Whilst recognizing the efforts done by the scientific community, there is a lot to be done to maintain soil health. Reducing tillage, maintaining soil cover, protecting the soil from erosion so as to maintain the soil biological function. A lot of the problem is due to over fertilization and overuse of chemicals. Its high time we shift to organic nutrients sources in order to rebuild organic matter and retain nutrients in the soils.
The way forward to addressing soil degradation
Given the importance of soil’s carbon absorption and storage functions, the avoidance, reduction and reversal of soil degradation could provide more than a third of the most cost-effective greenhouse gas mitigation activities needed by 2030. This would help to keep global warming under the 2 degrees threshold targeted in the Paris Agreement on climate change.
In order to restore the soil quality, the following strategies would be helpful in halting and reversing the soil degradation: –
· Encouraging Green Infrastructure development, reducing soil loss, remediation of contaminated land, and conservative agriculture.
· Mainstreaming sustainable land management practices in national development and conservation planning.
· Facilitating sustainable land management through policy and financial instruments
· Promoting Awareness of importance of preserving soil’s health
· Developing strategies to prevent biodiversity loss and help climate change mitigation and adaptation.
Improving knowledge of the probable future rates of soil erosion, accelerated by human activity, is important both for policy makers engaged in land use decision-making and for the earth-system modelers seeking to reduce uncertainty on global predictions (Borrelli et al., 2020). In line with general interest to all countries around the world to avoid a decrease in agricultural productivity (Satori et al., 2019) it is important that the issue of soil degradation be tackled.
Given the growing challenge of soil degradation, the time to act is now. It can be achieved through appropriate agricultural policy, interventions, and better soil governance.
The Future of humanity is in the Soil!
This is a wake-up call to avoid, reduce and reverse soil degradation while mitigation and adapting to climate change and halting biodiversity loss.
Dr. Sanjeev Narrainen is Integrity and Compliance Specialist with Green Climate Fund
The article has been republished with author’s permission
