Accelerated weathering mimics and speeds up the natural process of rock weathering to remove carbon dioxide (CO₂) from the atmosphere and store it in stable mineral forms[2][7]. This carbon sequestration approach involves enhancing the reaction between rocks, water, and air[2].
How it Works
Accelerated weathering fast-tracks natural rock weathering, which typically takes thousands of years, to a scale of years or decades. This acceleration is achieved by:
* Increasing the surface area of the rock[1].
* Selecting the most reactive rock types[1][6].
* Applying rocks to optimal soils and climatic conditions[1].
When rocks are exposed to the atmosphere, CO₂ reacts with water to form carbonic acid, which then reacts with the minerals in the rocks to form carbonates[6]. The application of crushed rock to soil sequesters carbon[6].
Implementations of Accelerated Weathering
1. Enhanced Weathering on Land: Involves spreading finely ground silicate rocks, like basalt or olivine, on agricultural lands[3], forests, or coastal areas[4]. This application can remove atmospheric CO₂, improve soil fertility[1], reduce ocean acidification, enhance crop yields[1], and amend degraded soils[1].
2. Ocean Alkalinity Enhancement (OAE): Adds alkaline substances, such as crushed limestone or olivine, to the ocean[8] or coastal lands[4] to increase seawater alkalinity and enhance CO₂ absorption[8][11]. This method can reduce ocean acidification and increase CO₂ sequestration in the ocean[8].
3. Direct Air Capture with Mineralization: Integrates mineral carbonation with direct air capture (DAC) technologies, reacting captured CO₂ with minerals to form stable carbonates[5].
Benefits
* Removes atmospheric CO₂ and stores it in stable mineral forms, aiding climate change mitigation[3][8].
* Enhances soil fertility by releasing essential nutrients and increasing pH levels, improving crop yields[1] and promoting sustainable agriculture[3].
* Reduces ocean acidification by increasing alkalinity and buffering capacity, protecting marine ecosystems and biodiversity[4].
* Uses widely available materials (such as basalt)[2], providing a scalable approach to carbon sequestration[10].
Challenges
* Requires sustainable sourcing and transportation of large quantities of rock materials, potentially impacting local environments and communities[10]. Mining exerts the dominant influence on environmental impacts[2].
* Potential impacts on soil and marine ecosystems need careful assessment and monitoring to avoid unintended consequences[3].
* Scaling up accelerated weathering requires significant investments in infrastructure and monitoring systems[5].
* Achieving significant carbon removal requires accelerating reaction rates, which may involve energy-intensive processes[5].
Enhanced Rock Weathering (ERW)
Enhanced Rock Weathering (ERW) fast-tracks natural carbon removal[1] and has many positive benefits for agriculture and land[1]. Spreading silicate rocks in soil can[1]:
* Increase crop yield and enhance agricultural productivity.
* Amend degraded soils.
* Build plant resistance against pests and diseases.
* Improve crop water retention, potentially increasing crop resilience to drought.
* Reduce the need for fertilizers.
Puro.earth has developed the first enhanced rock weathering (ERW) carbon crediting methodology and issues CO₂ Removal Certificates (CORCs) to carbon removal suppliers through the Puro Registry[1]. FabricNano is also using biology with geology, through enzymes, to offer a holistic approach[9].
By reacting with atmospheric CO₂, the process has the potential to sequester up to 2-4 tonnes of CO₂ per hectare per year. While offering opportunities, several limitations should be considered[3]. The most significant limitation is the cost, social acceptability, and potential unanticipated consequences that will limit utilization[3]. Urgent efforts to phase down fossil fuel emissions will need to occur to make the solution viable[3].
With careful planning, responsible implementation, and robust monitoring, accelerated weathering can play a vital role in achieving global climate goals[3] and promoting a more sustainable future.
Read More
[1] https://puro.earth/enhanced-rock-weathering
[2] https://en.wikipedia.org/wiki/Enhanced_weathering
[3] https://pubs.acs.org/doi/10.1021/acs.est.4c02368
[4] https://www.edf.org/sites/default/files/documents/Ocean%20Alkalinity%20Enhancement.pdf
[5] https://egusphere.copernicus.org/preprints/2025/egusphere-2025-447/
[6] https://blog.verde.ag/en/science-enhanced-rock-weathering/
[7] https://uol.de/en/icbm/microbiogeochemistry/research/accelerated-weathering-of-limestone
[8] https://oceanvisions.org/ocean-alkalinity-enhancement/
[9] https://fabricnano.com/blog/accelerated-rock-weathering-a-potential-game-changer-in-carbon-sequestration
[10] https://www.nature.com/articles/s43247-022-00436-3
[11] https://climateinterventions.org/interventions/ocean-alkalinity-enhancement/
[12] https://un-do.com/enhanced-weathering/