Estimating Carbon Dioxide Sequestration Potential of Enhanced Rock Weathering

Enhanced Rock Weathering (ERW) is being explored as a potential strategy for carbon dioxide removal (CDR) through the application of silicate minerals to agricultural lands. This approach leverages natural weathering processes to sequester carbon, with the effectiveness influenced by climatic conditions such as temperature and soil moisture.

Nature

The efficacy of ERW in sequestering carbon is significantly affected by biophysical factors, particularly temperature and soil excess water. Higher soil temperatures and increased moisture levels enhance carbon sequestration rates by accelerating weathering processes. The study utilizes data from the TerraClimate dataset, covering global annual mean temperature, cumulative precipitation, and evapotranspiration from 1980 to 2023, to inform its analysis.

Nature

The annual carbon sequestration rate under specific conditions is modeled using the equation \( K(T,E) = K_0 \times f(T) \times f(E) \), where \( K_0 \) is a baseline rate, and \( f(T) \) and \( f(E) \) are functions representing the effects of temperature and water surplus, respectively. The model incorporates a range of climatic scenarios to estimate the potential of ERW across different regions.

Nature

The study projects future ERW adoption shares and carbon sequestration rates using data from the Shared Socioeconomic Pathway 4 (SSP4), which reflects disparities in technological adoption between developed and developing regions. The model predicts that as global temperatures rise, the proportion of cropland allocated to ERW will increase, driven by heightened public awareness and policy support for climate mitigation.

Nature

The findings indicate that ERW could play a significant role in global efforts to mitigate climate change by enhancing carbon sequestration in agricultural systems. The model suggests that regions with favorable climatic conditions could become hotspots for ERW deployment, potentially leading to substantial reductions in atmospheric CO2 levels.

Nature

The research emphasizes the importance of integrating societal responses to climate change with technological solutions. The authors argue that as climate impacts worsen, public risk perception will likely increase, accelerating the adoption of ERW technologies.

Nature

While the study presents a promising outlook for ERW, critics may point to the challenges of widespread adoption, particularly in developing countries where economic barriers and technological access remain significant obstacles. Additionally, concerns about the long-term ecological impacts of large-scale mineral application could be raised.

Nature

There is a lack of consensus on the precise carbon sequestration rates achievable through ERW, as estimates can vary based on local environmental conditions and the specific minerals used. Further research is needed to validate the model's assumptions and refine projections.

Nature

• “In general, higher soil temperature and excess water enhance carbon sequestration through accelerated weathering rates56,57.” — Research Team

Nature

• “Accordingly, the choice of SSP4 aligns with our objective of projecting the unequal spatial and temporal paces of ERW adoption across regions and its implications for future climate change.” — Research Team

Nature

This comprehensive analysis of ERW highlights its potential as a viable CDR strategy, while also acknowledging the complexities and challenges that accompany its implementation.

Nature