The Brazilian Cerrado, a vast savanna covering roughly 26% of the country, harbors a surprising climate secret. New research reveals this often-overlooked ecosystem stores more carbon per unit area than the Amazon rainforest, a critical fact often missing from global carbon accounting. This isn’t just about biodiversity; it’s about water security, regional climate regulation, and the fate of millennia-old carbon deposits.
The Cerrado’s Carbon Superpower
The Cerrado’s wetlands, fed by groundwater, accumulate carbon in their waterlogged soils at a rate six times higher than Amazonian vegetation. These wetlands function as massive carbon sinks, storing an estimated 1,200 metric tons of carbon per hectare. To put that in perspective, while the soil isn’t technically “peat” by strict definitions, it contains comparable carbon density due to its sheer volume.
The study, published in New Phytologist, fills a significant data gap in tropical carbon cycle research. Researchers dug deep – literally – extracting meters-long soil cores across seven sites, revealing carbon layers dating back as far as 20,000 years. This age underscores the irreversible loss if these ecosystems are degraded.
Why This Matters Now
The Cerrado’s wetlands cover roughly 8% of the biome (16.7 million hectares), yet their carbon-storing potential has been largely ignored in Brazil’s national accounting. This oversight is critical because land use changes, agriculture, and climate change are already threatening these systems. The research team found that 70% of wetland emissions occur during the dry season, meaning droughts could trigger rapid carbon release as the soil dries out.
This is no academic detail. The Cerrado is already under pressure as a “sacrifice biome” – absorbing land use demands that would otherwise fall on the better-protected Amazon. This dynamic is flawed, as the Cerrado’s water flows support the Amazon, meaning its degradation undermines the very forest it’s meant to spare.
The Policy Gap
Brazilian law offers some wetland protection, but it often fails to safeguard the water sources that sustain them. Without holistic water management and stronger land-use regulations, the Cerrado’s carbon sink is at risk. The issue is urgent: these ecosystems are disappearing “silently, invisibly,” with little recognition from policymakers or the global scientific community.
“If we lose the carbon in the Cerrado that has accumulated for millennia, we can’t put it back so easily,” says ecologist Amy Zanne.
The findings underscore the need for better protection, including laws that recognize groundwater connectivity and enforce sustainable water usage. Ignoring the Cerrado’s crucial role will not only accelerate regional climate change but undermine global climate targets.
