Rewet dried wetlands to save 100bn tons of CO2

Some of the most degraded and damaged ecosystems on the planet can still be restored to offer a massive reduction in carbon emissions.

The restoration of wetlands that have either fully dried or degraded is a high priority for many countries looking to rebuild and repair biodiversity. But these habitats also play a crucial role in the battle to stop global warming from becoming significantly worse in the coming decades. 

When wetlands are covered in water, they emit methane in large quantities. While this gas contributes to warming and climate change, when wetland soil and plant roots are fully exposed because the landscape has dried, that flora begins to decompose, emitting huge amounts of carbon dioxide (CO2). Now researchers at the Southern University of Science and Technology in China have published a report suggesting the carbon captured by keeping wetlands wet, or restoring them to their natural state, easily offsets the methane released. 

The effect is so significant, in fact, that estimates suggest revitalising 4million square miles of degraded wetlands globally would lead to the capture and storage of between 100 and 400 gigatons of CO2 equivalent emissions by the end of the century. This is a greater positive impact than all combined reforestation projects countries have committed to at the time of writing. Meanwhile, stopping the degradation of wetlands still intact will avoid between 150 and 650 billion tons of emissions, with the greatest potential found in areas of Siberia, Canada, the Congo, Brazil and Indonesia. 

Earlier this year, a study suggested that 44% of the planet’s landmass would need to be protected in order to safeguard existing levels of biodiversity.