Grasslands are an Overlooked Carbon Sink Right Beneath Our Feet
If we are looking for a way to remove carbon from the air, we only need to look below our feet. While not a commonly thought of tool for mitigating climate change, studies show that grasslands have equal or greater potential for carbon sequestration than forests.
Most carbon sequestration focuses on afforestation — planting trees where there aren’t any — yet other habitats can provide a similar benefit. As a result, scientists and activists are pushing to restore grasslands at higher rates, arguing for the benefits grasslands provide as carbon sinks and wildlife habitats.
Grasslands may not seem to be a significant carbon sink, but their power lies in the ability to sequester carbon in the soil. This is beneficial, as they can store carbon and other nutrients in the soil for long periods. Unlike trees in forests that store carbon during lifespans and then release it back to the atmosphere during postmortem decomposition, grasses are constantly rejuvenating themselves.
Conversion to cropland is one of the greatest threats to the world’s grasslands. It causes habitat fragmentation and a loss of vital wild grazing species. In addition, degraded grasslands emit more carbon than they absorb, especially grasslands used for agriculture. To use grasslands as carbon sinks, they need to be restored just as with forests.
Grassland restoration can reduce soil erosion as the extensive root system holds soil in place. Grasslands are just as worth saving as forests though currently under-appreciated as compared to picturesque forests.
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Planting trees is the main focus of numerous environmental non-profits and carbon-trading schemes. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services and Intergovernmental Panel on Climate Change state that restoring carbon-rich ecosystems is one of the easiest and cheapest ways to mitigate climate change, but this often manifests as reforestation. Sixty countries have joined the Bonn Challenge to restore 350 million hectares of deforested and degraded land by 2030. The focus on tree-planting initiatives is good, but it neglects other valuable ecosystems.
Some scientists worry that focusing on tree-based carbon sequestration will reduce carbon stocks in the soil. Since trees hold most of their carbon above ground, they do not increase soil organic carbon as grasses do. In addition, grasslands are more resilient than forests in regions more susceptible to drought and wildfires. Perennial grasses can survive for years because of their root system, even through fires. A study from University of California Davis shows that, in some cases, under our current climate trajectory, grasslands are better carbon sinks than forests.
Unfortunately, afforestation often comes at the cost of grasslands: trees are planted on grasslands, which diminishes their size. Trees can sequester large amounts of carbon, but they hurt the wildlife dependent on those ecosystems when they replace grassland. Replacing grasslands with forests can also disrupt water flow in the surrounding area.
The benefits of grasslands speak to the need for conscious nature-based solutions. Instead of covering the entire planet with trees, we should instead look to restore nature in a way that respects the regionality of ecosystems. If the land was once grassland, we should prioritize healing that grassland instead of forcing a forest to live there. There are also cultural impacts to restoring habitats. Thoughtful and context-based solutions are needed to improve our ecosystems without hurting others in the process.
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