In recent years, the urgency of addressing climate change has led to a growing interest in carbon dioxide removal (CDR) as a tool for combatting this global emergency. As the concentration of carbon dioxide (CO2) in the atmosphere continues to rise, it's essential that we not only reduce emissions but also actively remove excess CO2. While there are various approaches to CDR, land-based solutions have been a mainstay of the carbon offset markets since their inception in the 1990s, and they continue to offer a promising pathway toward a more sustainable and greener future.
XPRIZE Carbon Removal is a $100 million competition encouraging innovators from around the world to find the most efficient and scalable CDR solutions. Teams developing “land” solutions are innovating a range of techniques that leverage both natural ecosystems and innovative technologies to capture and store carbon from the atmosphere. In particular, the competition’s 100-year durability requirement for sequestered CO2 challenges teams to explore ways to improve the durability of CO2 removed using land-based solutions.
METHODS OF OF LAND-BASED CDR
REFORESTATION AND AFFORESTATION
Planting trees on a massive scale remains one of the most straightforward land-based CDR methods. Trees absorb carbon dioxide during photosynthesis and store it as biomass. Reforestation and afforestation efforts can not only sequester carbon but also support biodiversity, improve soil health, and enhance water retention in ecosystems. An IPCC Special Report on Climate Change and Land estimated that reforestation and afforestation have the potential to mitigate 0.5 - 10.1 gigatonnes per year.
SOIL CARBON SEQUESTRATION
Soils also have the ability to store significant amounts of carbon through practices like cover cropping, agroforestry, and no-till agriculture. The estimated total carbon stored in terrestrial ecosystems is approximately 3170 gigatons of which nearly 80% is found in soil. Soil carbon sequestration techniques enhance soil health while locking carbon away in the ground for extended periods.
BIOENERGY WITH CARBON CAPTURE AND STORAGE
Bioenergy with carbon capture and storage involves cultivating energy crops, like switchgrass or silvergrass, which are cheap and easy to grow, burning them as fuel to produce bioenergy, and then capturing the CO2 emitted during combustion for long-term storage. This technique combines energy production with carbon removal.. The same IPCC Special Report estimates the mitigation potential of bioenergy with carbon capture and storage at 0.4 - 11.3 gigatonnes per year.
BLUE CARBON ECOSYSTEMS
Coastal habitats like mangroves, seagrasses, and salt marshes are excellent carbon sinks, storing carbon in the sediment they grow from. Protecting and restoring these so-called blue carbon ecosystems not only captures carbon but also provides invaluable coastal protection and habitat for marine life. It’s estimated that certain blue carbon ecosystems are 4 times more efficient at mitigating carbon than a forest ecosystem of the same size.
BENEFITS AND CHALLENGES OF LAND-BASED CDR
Land-based carbon dioxide removal offers numerous benefits beyond just reducing atmospheric CO2 levels. They can enhance ecosystem resilience, support biodiversity, improve local air and water quality, and provide socio-economic benefits to communities. These approaches can also be relatively low-tech, making them accessible to a wide range of regions and communities around the globe.
As we strive to meet global climate goals and secure a sustainable future, land-based carbon dioxide removal solutions offer a pragmatic and hopeful path towards a world with net-negative carbon emissions and a healthier environment for all. By investing in these solutions, as XPRIZE Carbon Removal is doing by incentivizing innovation in the field, we can turn the tide on climate change and create a legacy of stewardship for generations to come.
Learn more about land-based CDR by watching these videos on XPRIZE Carbon Removal teams Carbon Down Under and Landwärme & bioCORE. Carbon Down Under is developing a solution that converts waste biomass to a water-soluble liquid and stores it underground to be eaten by soil microbes, while Landwärme and bioCORE are building the first economically viable facility for the sequestration of biogenic CO2 for permanent storage.