Scientists have found that hidden wetlands in Brazil's Cerrado savanna hold up to 1,200 tons of carbon per hectare, six times the biomass of typical Amazon forests. Carbon dating shows this material has been in the ground for an average of 11,000 years, with some deposits up to 20,000 years old. The storage happens because waterlogged soils slow decomposition, locking carbon away for millennia. New mapping using remote sensing and machine learning suggests these wetlands cover about 64,500 square miles of the Cerrado, at least six times larger than earlier estimates. But agricultural expansion, drainage, and small dams are lowering water tables and triggering carbon releases. Unlike forests, these peatlands cannot recover stored carbon within human lifetimes if disturbed. The study warns that 47% of the Cerrado is now occupied by human uses, and hotter, drier conditions from climate change could accelerate carbon loss. Researchers say better mapping and stronger protection are needed to preserve these ancient carbon stores.
