Soils are a double-edged climate sword. They are huge reservoirs of organic carbon and can act as a carbon sink. But they can also release CO2 into the atmosphere when used unsustainably.
Author: Irene Banos Ruiz | Published: February 6, 2018
Forests are often called the lungs of the planet because of the way they “breathe” in carbon dioxide. The role they play in locking in carbon dioxide is so essential UN schemes promote forests conservation as a way to offset greenhouse gas emissions.
Soils, meanwhile — less beautiful, and oft forgotten beneath our feet — get less press. Yet they hold 70 percent of the planet’s land-based carbon — four times as much as all the world’s biomass and three times the amount of CO2 in the atmosphere.
Agriculture is responsible for around 13 of global greenhouse gas emissions. But if farms managed their soils more sustainably, they could lower that share considerably, scientists say.
And not only would they emit less greenhouse gases — as carbon reservoirs, agricultural soils could even mop up carbon already in the atmosphere. And that’s a win-win situation because once in the soil, carbon fertilizes plants, boosting agricultural yields.
Carbon – a valuable resource
Plants absorb carbon dioxide during photosynthesis. Some is released back into the atmosphere and some is stored in plant matter. When that biomass is broken down by microorganisms in the soil, it becomes an organic material called humus, which nourishes plants and other organisms, conserves water and balances the soil’s pH level.
“This carbon is like the fuel for any soil,” Ronald Vargas, soils and land officer at the UN Food and Agriculture Organization (FAO), told DW.