Brazil’s soil stores equivalent of 70 years of CO2 emissions, warns study

A report by MapBiomas has revealed that Brazil’s soil stores the equivalent of 70 years of carbon dioxide (CO2) emissions in the country, emphasizing the importance of preserving native vegetation cover.

The study highlights that out of the total 37 billion tons of soil organic carbon (COS) in Brazil in 2021, nearly two-thirds (63%) are stored in soils under stable native cover (23.4 billion tons of COS).

Only 3.7 billion tons of COS are stored in soils in areas converted to human use since 1985.

The Atlantic Forest and the Pampas exhibit the highest average soil organic carbon stocks per hectare, with an average of 50 tons per hectare (t/ha) and 49 t/ha, respectively.

The Amazon region has an average of 48 t/ha, while the Caatinga biome in northeastern Brazil has the lowest reserves with an average of 31 t/ha.

In terms of absolute reserves, the Amazonia region holds the largest COS reserve in Brazil, measuring 19.8 billion tons in 2021.

However, from 1985 to 2021, the carbon stored in Brazil’s forest-covered soil decreased from 26.8 billion tons to 23.6 billion tons, resulting in a loss of 3.2 billion tons.

This loss is greater than the entire COS stock of the Caatinga in 2021 (2.6 billion tons) and equivalent to almost six years of Brazil’s greenhouse gas emissions.

MapBiomas explains that soil is one of the largest carbon reservoirs on the planet, alongside the atmosphere, oceans, and plants.

When soil undergoes degradation, it can release carbon into the atmosphere in the form of CO2 and methane, exacerbating climate change.

Professor Taciara Zborowski Horst, one of the mapping coordinators, emphasizes the importance of preserving soil as a carbon reserve and directing efforts towards agriculture practices that store carbon and minimize carbon emissions.

The study underscores the need to consider soil preservation alongside above-ground preservation in discussions on public policies and environmental discourse.

It warns that agricultural use and conversion to pasture pose a risk of carbon emissions from soils with high carbon stocks.