Isometric has issued the world’s first certified River Alkalinity Enhancement (RAE) credits to CarbonRun. 76 credits were generated by CarbonRun’s Kvina River Project in southern Norway, to be delivered to Frontier buyers including Stripe, Shopify, and McKinsey Sustainability.
This marks a major milestone for a carbon removal pathway with the potential to remove millions of tonnes of carbon dioxide from the atmosphere each year. Rivers are the main way carbon moves across land to the ocean—and in the process, they release up to 2.5 billion tonnes of carbon dioxide into the atmosphere annually.
RAE addresses carbon emissions by accelerating the Earth’s natural weathering process. Finely crushed limestone is dissolved into river water, where it reacts with acidic carbon dioxide to form stable carbonate and bicarbonate ions. This reaction prevents carbon dioxide from being released into the atmosphere. These stable ions are carried downstream to the ocean, where the carbon is safely stored for tens of thousands of years.
This approach builds on river liming, a practice used for decades to restore water quality and remedy the effects of acid rain, notably in salmon rivers.
The credits will be delivered under Frontier’s $25.4 million offtake agreement with CarbonRun to remove 55,442 tonnes of carbon dioxide between 2025 and 2029.
Hannah Bebbington Valori, Head of Deployment at Frontier, said: “River liming for carbon removal is low‑cost, scalable, and relatively straightforward to measure—a rare combination that makes it a particularly promising carbon removal pathway. The first certified credits mark an important step for an approach that remains underexplored and underfunded relative to its potential.”
CarbonRun selected the Kvina River for its RAE project due to its history of river liming and the potential for positive impacts on the river’s ecosystem. The project operates in close collaboration with local authorities and scientific partners, with continuous monitoring to ensure ecological safety and robust measurement of carbon removal.
Shannon Sterling, PhD, Founder, and Chief Scientific Officer of CarbonRun, said: “This first issuance of RAE credits demonstrates what rigorous science, continuous monitoring, and responsible deployment can achieve. Rivers are already responding to climate pressures—warming, acidification, ecological stress—and River Alkalinity Enhancement gives us a way to strengthen these systems while delivering durable carbon removal.
"The Kvina project shows that when local expertise, strong data, and transparent MRV come together, RAE can operate safely and effectively at scale. This milestone is an important proof point for the field and a foundation for the global work ahead.”
These credits were issued under Isometric’s industry-first River Alkalinity Enhancement Protocol, which applies a scientifically rigorous approach to monitoring, reporting, and verification (MRV). The protocol uses a flexible quantification framework, supported by direct measurements along the river’s course and a dynamic baseline, to capture river conditions and ensure carbon removal is quantified accurately and conservatively.
The Kvina River project was independently validated and verified by 350Solutions, and the underlying data and documentation behind each credit are publicly available on the Isometric Registry.
This issuance marks a major step forward for river-based carbon removal, demonstrating for the first time that RAE can be accurately quantified and certified.
