Organic Carbon in Soils of the World

TLDR

Soil carbon stores nearly three times the aboveground biomass and about twice the atmosphere, yet reliable estimates are hampered by limited global soil data. Using new databases, the study aims to deliver more reliable global soil carbon estimates than prior work. Globally, 1576 Pg of C is stored in soils, 32 % of which lies in tropical soils, of which 40 % is in forest soils, and deforestation can cause 20–50 % loss of this carbon mainly via erosion.

Abstract

The C stored in soils is nearly three times that in the aboveground biomass and approximately double that in the atmosphere. Reliable estimates have been difficult to obtain due to a lack of global data on kinds of soils and the amount of C in each soil. With new data bases, our study is able to provide more reliable data than previous estimates. Globally, 1576 Pg of C is stored in soils, with ≈ 506 Pg (32%) of this in soils of the tropics. It is also estimated that ≈ 40% of the C in soils of the tropics is in forest soils. Other studies have shown that deforestation can result in 20 to 50% loss of this stored C, largely through erosion.