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 existential challenge. 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 a variety of approaches to CDR—including rock-, air-, and ocean-based solutions—land-based solutions have been a mainstay of the carbon offset markets since their inception in the 1990s. Today, they continue to offer a promising pathway toward a more sustainable and greener future.
XPRIZE Carbon Removal is a $100 million competition incentivizing innovators from around the world to find the most efficient and scalable CDR solutions to stabilize the Earth’s climate. Teams developing solutions in our Land track are leveraging both natural ecosystems’ carbon capture ability and innovative technologies to capture and store carbon from the atmosphere.
METHODS OF LAND-BASED CDR
REFORESTATION AND AFFORESTATION
Planting trees on a massive scale remains one of the most straightforward land-based CDR strategies. The benefits of reforestation for carbon sequestration are numerous. Perhaps the most well-known is that trees absorb CO2 during photosynthesis, resulting in biomass carbon storage. There are many more though—as companies and individuals invest in reforestation and afforestation (creating forests in previously unforested areas) they are also supporting biodiversity, improving soil health, and enhancing water retention in ecosystems. An IPCC Special Report on Climate Change and Land estimates that reforestation and afforestation have the potential to mitigate 0.5 - 10.1 gigatonnes of carbon 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. For many teams, this also included creating biochar, a stable charcoal-like substance made by heating biowaste without oxygen. The estimated total carbon stored in terrestrial ecosystems is approximately 3,170 gigatonnes, of which nearly 80% is found in soil. Soil carbon sequestration techniques like biochar 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.
GEOLOGIC CARBON SEQUESTRATION
In geologic carbon sequestration, captured carbon dioxide is stored deep underground in the empty spaces and pores between rocks in underground geologic formations. This captured carbon can come from a variety of sources including the atmosphere through direct air capture or as biowaste from agricultural byproducts.
BENEFITS AND CHALLENGES OF LAND-BASED CDR
The role of land-based CDR in climate change mitigation stretches beyond just reducing atmospheric CO2 levels. These innovations can enhance ecosystem resilience, support biodiversity, improve air and water quality, and provide socio-economic benefits to local communities. These approaches can also be relatively low-tech, making them accessible to a wide range of regions and communities around the globe.
Out of the 1,300 teams from 88 countries that competed in the XPRIZE Carbon Removal competition, XPRIZE chose 20 finalist teams, including five Land track teams: Applied Carbon, MASH Makes, NetZero, Takachar, and Vaulted Deep. This final phase before the competition’s end included site visits to see the innovative technology in action, and robust validation procedures.
Learn more about these competing teams and their technology in our recently released Land track episode of our XPRIZE Carbon Removal docuseries. This series covers each of our prize tracks, and you can watch each episode now to learn about our finalist teams across all four tracks!
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