Why soils matter
Soils are complex, three-dimensional landscape elements and essential parts of terrestrial ecosystems. They hold more organic carbon than the atmosphere or the world’s living vegetation, making them an important part of the global carbon cycle. Soils vary widely in their chemical, physical and biological properties. These properties develop through interactions among factors such as climate, geology, water and living organisms. You can find an overview of different soil types here.
Storing organic carbon is an important soil function, but the amount stored — and how quickly it changes — varies greatly from one soil to another. Land use, management and climate change can all cause soil carbon stocks to rise or fall. Even in places with similar climate, geology and water conditions, differences in land use can lead to substantial differences in the amount of carbon stored. In some cases, stocks may vary by as much as 50%.
Two factors are especially important: how much organic material enters the soil, and how quickly and efficiently it is broken down. Both can be influenced by humans. This is why changes in land use and management can help soils store more carbon, thereby providing carbon sinks — although the outcome depends on the soil, the practices used and how long their effects last.
