This week’s publication highlights relate to carbon pricing, marine CDR, bioenergy with carbon capture and storage and enhanced rock weathering.
Pigou’s Advice and Sisyphus’ Warning: Carbon Pricing with Non-Permanent Carbon Dioxide Removal
Abstract
This paper develops a welfare and public economics perspective on optimal policies for carbon removal and storage (CDR) in permanent and non-permanent sinks. Non-permanent CDR reduces mitigation costs, even though the stored carbon is released into the atmosphere eventually. It may serve as bridge technology until permanent CDR becomes available. In contrast to permanent removals, non-permanent CDR does not reduce the optimal long-run temperature level. Its valuation differs from the social cost of carbon since a social cost of carbon removal arises from marginal damages caused by emissions released from non-permanent storage. We discuss three policy regimes that ensure optimal deployment of non-permanent CDR in terms of their informational and institutional requirements for monitoring, liability, and financing.
Franks, M. et al. (2026) Pigou’s Advice and Sisyphus’ Warning: Carbon Pricing with Non-Permanent Carbon Dioxide Removal 89 (11) Environmental and Resource Economics.
Read the full paper here: Pigou’s Advice and Sisyphus’ Warning: Carbon Pricing with Non-Permanent Carbon Dioxide Removal I Environmental and Resource Economics.
Decoupled Timescales of Organic Carbon and Phosphorus Recycling in the Global Ocean
Abstract
The ocean’s biological carbon pump exports atmospheric CO2 to the deep ocean, where it can remain sequestered for decades to centuries, and attempts to artificially enhance this natural carbon sink by fertilizing portions of the open ocean could help mitigate the impacts of excessive anthropogenic CO2 emissions. However, differences in the cycling rates of carbon and other nutrients may impact the long-term response to ocean fertilization. In this study, we use a steady-state global biogeochemical inverse model, optimized to match hydrographic observations, to examine how differential production, remineralization, and circulation-driven re-exposure timescales of organic carbon and phosphorus affect long-term carbon sequestration. We partition global organic matter production based on the time required for regenerated carbon and phosphorus to return to the ocean surface. We find that less than 15% of total organic carbon and 31% of total organic phosphorus production remains sequestered in the ocean interior for 1 y, with only 3.3% (1.8 Pg C y−1) and 8.3% (0.046 Pg P y−1), respectively, remaining for a century or longer. The C:P ratio of the sequestration flux declines with increasing residence time, from 255:1 for total production to 98:1 for material sequestered for 100+ years, indicating that carbon is recycled to the surface more rapidly than phosphorus. This decoupling between carbon and phosphorus sequestration timescales could result in a “productivity hangover,” where the slow recovery of surface phosphate leads to a long-term suppression of global productivity, reducing the net removal of atmospheric CO2.
Sullivan, M. et al. (2026) Decoupled Timescales of Organic Carbon and Phosphorus Recycling in the Global Ocean 123(8) PNAS.
Read the full paper here: Decoupled Timescales of Organic Carbon and Phosphorus Recycling in the Global Ocean I PNAS
Mechanisms, Processes and Implications of Blue Carbon Sequestration and Pollution Control for Climate Change Mitigation
Abstract
Mangroves, seagrass beds, and salt marshes are examples of blue carbon ecosystems that are essential to the global carbon cycle because they store atmospheric CO2 in biomass and sediments. In order to assess the biogeochemical processes, sequestration rates, and environmental factors that control carbon storage and emissions in these ecosystems, this study summarizes data from peer-reviewed research published over the previous 20 years. Seagrass and salt marsh systems sequester 30–218 g C m⁻2 yr⁻1 and 150–250 g C m⁻2 yr⁻1, respectively, whereas mangroves have considerable belowground carbon storage (up to 1,023 Mg C ha⁻1) supported by anoxic, sulfate-reducing sediments and vertical accretion rates of 3–10 mm yr⁻1. Additionally, we evaluate carbon-loss mechanisms that might turn blue carbon sinks into net carbon sources, such as sediment erosion, methane generation, and oxidation after disturbance. Sea level rise, nitrogen loading, hydrological changes, and pollution are some of the factors that affect carbon stability and sequestration effectiveness. Our research as a whole shows that while restoration can recover 50–90% of depleted carbon stocks over several decades, intact blue carbon ecosystems significantly contribute to climate mitigation. These results highlight the significance of protecting coastal ecosystems and incorporating blue carbon solutions into frameworks for carbon offsets, pollution management, and climate adaption.
Dinakarmur, Y. et al. (2026) Mechanisms, Processes and Implications of Blue Carbon Sequestration and Pollution Control for Climate Change Mitigation 3(5) Discover Oceans.
Read the full paper here: Mechanisms, Processes and Implications of Blue Carbon Sequestration and Pollution Control for Climate Change Mitigation I Discover Oceans.
Integrated Biogasification and Carbon Capture Pathways: A System-Level Review of Technologies, Storage Options, and Deployment Challenges
Abstract
Carbon-negative energy systems that integrate bioenergy production with permanent carbon dioxide (CO2) sequestration are increasingly recognized as essential for achieving global net-zero and beyond-zero climate targets. While extensive research exists on individual components such as biogasification, carbon capture technologies, and geological storage, a coherent system-level synthesis linking these pathways remains fragmented. This review addresses this gap by providing an integrated assessment of biogasification-based carbon capture and storage (CCS) systems, with particular emphasis on techno-economic performance, capture efficiency, subsurface storage options, and deployment challenges. Following the PRISMA 2020 guidelines, 112 studies were systematically selected from an initial pool of 780 publications and analyzed to compare advanced gasification routes, emerging capture technologies, and storage strategies. The results indicate that hybrid gasification–solid oxide fuel cell systems can achieve efficiencies of up to 55%, while cryogenic carbon capture consistently delivers CO₂ purities above 95% with reduced energy penalties. Supercritical water gasification and hydrothermal pathways demonstrate strong potential for wet biomass conversion, achieving hydrogen yields exceeding 1150 mmol/L and carbon efficiencies above 80%. Despite these technical advances, large-scale deployment remains constrained by high costs (USD 800–1350 per tonne CO2), infrastructure limitations, and policy uncertainty.
Upreti, K. et al. (2026) Integrated Biogasification and Carbon Capture Pathways: A System-Level Review of Technologies, Storage Options, and Deployment Challenges 46(15) Environmental Systems and Decisions.
Read the full paper here: Integrated Biogasification and Carbon Capture Pathways: A System-Level Review of Technologies, Storage Options, and Deployment Challenges I Environmental Systems and Decisions.
Spatiotemporal Soil Fertility Responses to Enhanced Rock Weathering along a Hillslope Catena within a Temperate, Agricultural Watershed
Abstract
Enhanced rock weathering (ERW) is a promising strategy for removing carbon dioxide from the atmosphere, yet field-scale observations suitable for evaluating ERW co-benefits related to soil-fertility improvements within temperate agriculture settings remain scarce. We conducted a 2.5-year investigation within a headwater catchment at the Sleepers River Research Watershed in Danville, Vermont, applying 20 t ha−1 of finely milled, calcium-rich meta-basalt to near-stream pastures and adjacent, upslope hayfields. After establishing a year-long baseline, we continued to monitor topsoil chemical fertility indicators (pH, exchangeable essential nutrients, and cation exchange capacity) for 13 months following basalt application to evaluate changes relative to untreated control transects. The basalt amendment significantly raised soil pH by 0.15–0.24 units (p < 0.05) and increased exchangeable calcium by as much as 12%, with larger pH gains in soils that were initially more acidic. Other nutrients showed only modest responses, partly reflecting slow dissolution of metamorphic minerals rich in potassium and magnesium, such as chlorite, actinolite, and sericite present in the applied meta-basalt. Higher background variability in the pasture may have muted the detectable basalt-treatment signal, yet across the hillslope catena, the magnitude of pH change scaled inversely with initial pH (lowest at the shoulder and foot), illustrating the role of land use and topographic position in modifying ERW responses. These results indicate that calcium-rich meta-basalt acts as a slow-release liming agent in well-buffered temperate soils and provide indications of the co-benefits of ERW to improving soil health within temperate agroecosystems.
Zacharias, Q. et al. (2026) Spatiotemporal Soil Fertility Responses to Enhanced Rock Weathering along a Hillslope Catena within a Temperate, Agricultural Watershed 132(25) Nutrient Cycling in Agroecosystems.
Read the full paper here: Spatiotemporal Soil Fertility Responses to Enhanced Rock Weathering along a Hillslope Catena within a Temperate, Agricultural Watershed I Nutrient Cycling in Agroecosystems.