Addressing the crisis of climate change requires action on several fronts. We now need large-scale deployment of carbon removal alongside critical reductions in emissions. Carbon removal refers to natural or technological approaches for removing carbon dioxide from the atmosphere.
We're a non-profit that analyzes carbon removal opportunities based on the best available science and data. We help organizations make specific decisions towards their carbon removal goals. And we work collaboratively to build open tools and resources for the evaluation and deployment of carbon removal and other climate solutions.
We collaborate with researchers to build open source data and tools for carbon removal and climate solutions. Through this work we produce datasets, models, interactive articles, and commentary on climate policies and programs.
We work across a range of strategies that remove carbon dioxide from the atmosphere.
Forests are natural carbon sinks, capturing carbon dioxide from the atmosphere through the chemical reactions of photosynthesis and storing it in their biomass, about half of which is carbon. Carbon removal projects with forests can include planting trees or other vegetation to restore existing forests, or preventing deforestation, which enhances the natural carbon sink — but all remain at risk to natural or human disturbance.
Soil carbon sequestration occurs when changes to land management practices increase the storage of carbon in soils. Practices include the addition of cover crops, changes from conventional tillage to no tillage, and applying soil amendments. In theory, these practices can both increase soil storage and crop health, but they must be maintained over time for effective carbon removal.
When biological systems sequester carbon, it ends up in a form that will eventually decompose and result in carbon dioxide emissions. It is possible to take biomass and convert it to some more durable form, such as building materials or biochar. While producing these materials on its own is not carbon removal, the complete system of biomass production and carbon storage removes carbon dioxide from the atmosphere.
Direct air capture is a class of technologies that use synthetic sorbents or solvents that selectively bind carbon dioxide. Large contactors housing these chemicals use fans to expose them to carbon dioxide, and chemical separation is then used to recover the carbon dioxide in pure form. The resulting stream can be combined with mineralization or geological injection to achieve permanent carbon removal.
When alkaline materials react with carbon dioxide they form solid carbonate minerals that can achieve effective permanent carbon removal. Source materials include naturally occurring silicates like olivine and serpentine, or wastes from mining operations. Specific implementations can include grinding minerals for reaction with carbon dioxide in ambient air, or injecting pure carbon dioxide into alkaline-rich geological formations.
The world's oceans are vast carbon sinks with a critical role in the carbon cycle. At least two pathways may accelerate uptake and storage of carbon in the ocean. The first is to enhance the productivity of organisms in the ocean, such as phytoplankton. The second is to increase the store of inorganic carbon in the ocean through the extraction, processing, and dissolution of minerals. Both have enormous potential scale, but require significant research and testing.