Enhanced weathering is a nature-based carbon removal technology with the potential to permanently lock away CO₂ from the atmosphere. This carbon removal approach is receiving increasing interest given its great scaling potential and co-benefits such as crop yield increase. There are, however, still several key questions that need to be addressed and scientific consensus needs to be reached on the exact reactions and kinetics that occur in the enhanced weathering process.

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One of the aims of the Catalyst program is to share knowledge and insights on key CDR topics and provide a platform for knowledge exchange. This is the first of a series of blog posts where we will do a deep dive into enhanced weathering. In this first post, we will provide a brief overview of the key concepts of this CDR approach and introduce our current Catalyst participants developing enhanced weathering projects. ‍

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A brief background on enhanced weathering 

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The geological process of mineral weathering has happened naturally for millions of years. It is a process in which rocks are broken down into smaller particles and dissolved into water over time (physical and chemical weathering). This process plays a crucial role in the earth's carbon cycle by removing CO₂ from the atmosphere and storing it in the form of dissolved bicarbonates. They are formed through the reaction of CO₂ with silicate minerals in the presence of water. These dissolved bicarbonates then drain away through groundwaters and rivers, eventually ending up in the oceans where they precipitate in the form of calcium or magnesium carbonate and remain there for thousands of years. This is how the weathering of rocks removes CO₂ from the natural carbon cycle for millennia. The process takes hundreds to thousands of years in nature but can be artificially accelerated through human intervention.

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The basic idea of enhanced weathering is to speed up the natural process of weathering by finely grinding rock to increase its surface area and reactivity. The potential of CO₂ sequestration using enhanced weathering is very promising and there is significant interest from the scientific community and industry. Research institutions in collaboration with start-ups are investigating different aspects of enhanced weathering from mineral selection to delivery methods, and economic viability. The basic scientific principles of enhanced weathering are well understood but unclear regarding the exact kinetics of weathering (how fast the rock powders dissolve), and the most reliable methods to measure the sequestration of CO₂. Therefore, these are currently the subjects of extensive research efforts.

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Through the Catalyst program, Carbonfuture aims to bring together companies facing similar challenges, encourage the exchange of information and work together towards finding solutions. Among our Catalyst participants are three startups that set out to contribute to these efforts with the aim of reaching consensus on a method to reliably measure and verify the amount of carbon captured through enhanced weathering.  

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Lithos Carbon 

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The startup founded in 2022 by former tech founder Mary Yap and two world-class geochemists Dr. Noah Planavsky and Dr. Chris Reinhard, deploys carbon dioxide mineralization through enhanced rock weathering on managed lands, with software for optimized deployment and novel, cost-effective empirical attribution. Basalt rock dust is applied to farmland, where it reacts with rainwater, converting atmospheric CO₂ to dissolved bicarbonate and releasing macro- and micronutrients to the soil. Over time, dissolved bicarbonate is then transferred by rivers and streams to the coastal ocean, where it remains stable long-term. Eventually, dissolved bicarbonate reacts to form calcium carbonate minerals that are permanently deposited on the ocean floor. About three tonnes of basalt are needed to capture one tonne of CO₂, but the capture rates, safety, and efficiency depend on a highly engineered process - which Lithos has honed. Lithos’ modeling pipeline is backed by long-term research conducted at Yale University and the Georgia Institute of Technology. The venture traces the captured carbon as it moves through different ecosystems, starting at the moment of application at the farm, following runoff and erosion through rivers and streams, to the point it enters the ocean. 

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In October 2022, the startup from the US closed a $6.3M seed round to support Lithos’ vision “to shape the future of low-cost, highly-scalable, and directly-measured carbon removal in agriculture”, Mary Yap, CEO and Co-Founder. ”We will ramp up our team and scale the deployment of our enhanced rock weathering technology.” ‍

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Silicate 

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Silicate is an Ireland-based carbon removal company leveraging the massive potential of surplus concrete from the building industry to safely and permanently remove excess CO₂ from the atmosphere. The company’s roots are both in agriculture and geochemistry, with founder Maurice Bryson beginning Silicate after years working on some of the world’s largest farms, and science lead Prof. Frank McDermott of University College Dublin building on his decades of experience as a low temperature geochemist.

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The company’s dedication to the scientific integrity of their solution has seen them forge new paths in enhanced weathering. They are the first company in the world to utilize returned concrete for this process, untapping a previously idle source for durable carbon removal. Similar to Lithos’ approach, Silicate processes the material and works with farmers to spread the crushed concrete on their fields. The startup uses the geochemical reactivity of their returned concrete material to sequester shallow-soil CO₂ as soluble groundwater bicarbonate, leading to carbon removal lasting millennia. In addition to providing a durable carbon removal solution, their material can have co-benefits to the crops where it is applied, with the silica contained in it potentially boosting plants’ natural resistance to pests, lessening the need for agrichemical inputs. “We believe that returned concrete can be an affordable, rapidly scalable, and durable carbon removal solution that until now has not been harnessed. We see massive potential in this material and are demonstrating this empirically through our field and lab projects”, says Maurice Bryson, founder of Silicate. 

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In the last couple of months, Silicate has been focused on measuring the mass of carbon they are drawing down from their largest pilot project to date: 1,000 tonnes of crushed returned concrete which was applied to agricultural land in August 2022. “We are getting lots of amazing data from the August 2022 application of material, which is helping us shape the next application”, says Maurice. The upcoming project will be bigger again, using 2,000 tonnes of crushed returned concrete applied to 300 hectares of farmland in Ireland during spring 2023. Silicate is expanding its science team to help gather quality data from these large-scale projects, with the overarching goal being to create a robust, scalable and verifiable measurement protocol that can be readily applied across multiple mineral and rock types.‍

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InPlanet 

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Niklas Kluger and Felix Harteneck, Founders of InPlanet, are focusing their efforts on the tropics, where enhanced weathering of Silicate rock has the highest potential while also helping to regenerate tropical soils and fertilize crops. Silicate rock reacts with water and CO₂ and as a result, dissolved bicarbonates are produced.

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With its pilot projects in Brazil, InPlanet is building the first fully integrated platform to connect quarries, farmers, and the global carbon market. There, the startup is testing novel MRV mechanisms to develop tools for the accurate quantification, verification, and certification of carbon removal credits based on enhanced weathering technology which is essential to ensure that each carbon sink is properly documented. Additionally, the startup aims to empower farmers in tropical regions to replace conventional chemicals used in their farming practices with natural rock powders from local mines. Niklas, COO and Co-Founder, who is living in Piracicaba, São Paulo, where Inplanet incorporated its first subsidiary, is building strategic partnerships and organizing further pilot projects. As part of his daily routine, he visits mines and farmers in the region to verify MRV protocols as well as to gain an understanding of the operations and logistics behind spreading rock powder on agricultural land at scale. In February 2023, InPlanet’s science team implemented the first tropical Field Monitoring Station at the University of São Paulo to accelerate qualitative and quantitative data collection for robust MRV. 

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Earlier this year, InPlanet closed an oversubscribed €1.2M pre-seed round from leading impact and climate investors. “We are thankful for the support of our pre-seed investors and excited to use the funding to grow our team”, says Felix CEO and Co-Founder. Currently a team of seven, the startup is looking to grow to a total of twelve team members by the end of March, which will help expand their operations: “In 2023, we plan to spread 50.000 tonnes of rock powder to remove 10.000 tonnes of CO₂. This will allow us to generate unique and scientifically valuable data to understand the weathering process in the tropics even better.”  Alongside support from Carbonfuture and the Catalyst program, and after receiving initial funding from the Frontier and ClimAccelerator programs, this most recent funding round will get them closer to achieving their concrete goal.

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To sum it up: Enhanced weathering is one of the most promising nature-based carbon removal technologies, but there’s a dearth of high-quality, cradle-to-grave carbon MRV to get it off the ground. Our three Catalyst participants are currently combining their efforts to generate reliable and comparable data from their models and field trials, so stay tuned for more insights to come in this series of blog posts!