How healthy soil can mitigate Climate Change.
Land degradation such as unsustainable farming practices, industrial activities, mining, untreated urban waste and other non-environmental friendly practices are all human activities that affect our soil.
World Soil Day is held annually on 5th December, to raise awareness of the importance of soil quality for human well-being, food security and ecosystems. Soil carbon that is released into the atmosphere, through land degradation, is a big contributor to climate change.
Karen Shippey, Chief Director for Sustainability at the Department of Environmental Affairs and Development Planning (DEA&DP) says: “Soil is essentially a non-renewable resource as it takes years, decades, even centuries, to grow a centimetre of healthy topsoil.”
Soil is the second largest carbon store, or ‘sink’, after the oceans. Carbon sinks absorb and store carbon from the atmosphere helping reduce the greenhouse effect. Shippey adds that often people don’t see the link between climate change and soil but in actual fact when plants photosynthesise, they draw carbon out of the atmosphere and it gets distributed through the roots of a plant, the surplus of which is deposited in the soil.
“If undisturbed, this carbon can become stable, and remain locked away for thousands of years. Healthy soils can thus mitigate climate change. But they also help us adapt and be able to withstand climate change impacts. Soil provides both a solution to the cause, and an answer to the impending problems associated with climate change.”
Healthy top soils provide a sponge-like effect that can absorb rainfall, reduce the risks of floods, retain water and increase storage of groundwater.
“These are all vital functions required in a warming world where more severe floods and droughts are expected in the Western Cape,” says Shippey.
In South Africa there is limited fertile land and the majority of crop farmers need to increase the fertility of their soils to achieve good crop yields and those in fertile soil areas also need to maintain the fertility of their soils, as frequent cropping depletes the soil of nutrients. A dependence and overuse of synthetic fertilisers, pesticides and herbicides reduces long-term soil fertility, causes soil erosion, pollutes water supplies, poisons fragile ecosystems, exposes farmers and farm workers to toxins, and contributes to climate change through greenhouse gas emissions.
Annually, we’re still losing an estimated 500 million tons of sediment, composed of mainly soil and topsoil. Much of this is occurring in the little arable land that we have. Over 60% of the national terrestrial carbon stock is located in grassland and savanna ecosystems in the northern parts of South Africa. Within these two ecosystems, more than 90% of the total carbon pool is located below ground mainly in the form of soil organic carbon.
“The Western Cape has lower carbon stocks in the soils of the Fynbos and Karoo ecosystems, but these are still equally important not only for soil carbon stocks but for maintaining soil functionality that will continue to support both crops, grazing lands and natural ecosystems that provide us with food, water, and climate buffering functionality through spongy soils that protect us from droughts and floods,” says Shippey.
As provincial government, the Western Cape Climate Change Response Strategy, The SmartAgri Plan and the Western Cape Provincial Biodiversity Strategy and Action Plan collectively aim to tackle this challenge through multiple programmes and interventions.
Shippey adds that ending land degradation and restoring degraded land would get humanity one third of the way to keeping global warming below 2°C (or 1.5.C), the target climate scientists say we need to avoid the most devastating impacts to human civilisation.