eCite Digital Repository
CO2 removal with enhanced weathering and ocean alkalinity enhancement: potential risks and co-benefits for marine pelagic ecosystems
Citation
Bach, LT and Gill, SJ and Rickaby, REM and Gore, S and Renforth, P, CO2 removal with enhanced weathering and ocean alkalinity enhancement: potential risks and co-benefits for marine pelagic ecosystems, Frontiers in Climate, 1, (OCT) Article 7. ISSN 2624-9553 (2019) [Refereed Article]
![]() | PDF 3Mb |
Copyright Statement
Copyright 2019 Bach, Gill, Rickaby, Gore and Renforth. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/
DOI: doi:10.3389/fclim.2019.00007
Abstract
Humankind will need to remove hundreds of gigatons of carbon dioxide (CO2) from the atmosphere by the end of the twenty-first century to keep global warming below 2°C within the constraints of the global carbon budget. However, so far it is unclear if and how this could be achieved. A widely recognized idea is to accelerate weathering reactions of minerals that consume CO2 when they dissolve. Acceleration could be realized by pulverizing and distributing gigatons of these minerals onto land (termed "enhanced weathering (EW)") or sea (termed "ocean alkalinity enhancement (OAE)") thereby largely increasing their reactive surfaces. However, the desired consumption of atmospheric CO2 during dissolution would inevitably be accompanied by a release of mineral dissolution products (alkalinity, Si, Ca, Mg, Fe, Ni, and maybe others). Here, we approximate their maximum additions to assess potential consequences for pelagic communities (mainly primary producers) and the biogeochemical fluxes they control. Based on this assessment, we tentatively qualify the potential to induce positive and/or negative side effects to be high for Fe, Ni, Si, intermediate for alkalinity, and low for Ca and Mg. However, perturbation potentials are always higher at perturbation hotspots and would be different for EW than for OAE. Furthermore, ecological/biogeochemical consequences of EW/OAE largely depend on the minerals used. We hypothesize that mainly calcifiers would profit in a scheme where CaCO3 derivatives would be used due to beneficial changes in carbonate chemistry. Figuratively, this may turn the blue ocean into a white(r) ocean. When using silicates, the release of additional Si, Fe and Ni could benefit silicifiers and N2-fixers (cyanobacteria) and increase ocean productivity ultimately turning the blue ocean into a green(er) ocean. These considerations call for dedicated research to assess risks and co-benefits of mineral dissolution products on marine and other environments. Indeed, both EW and OAE could become important tools to realize CO2 removal at the planetary scale but associated risks and/or co-benefits should be revealed before deciding on their implementation.
Item Details
Item Type: | Refereed Article |
---|---|
Keywords: | CO2 removal, negative emissions, enhanced weathering, ocean alkalinity enhancement, plankton, geoengineering, risk assessment, iron, nickel, silicon, silicification, calcification |
Research Division: | Earth Sciences |
Research Group: | Oceanography |
Research Field: | Biological oceanography |
Objective Division: | Environmental Policy, Climate Change and Natural Hazards |
Objective Group: | Mitigation of climate change |
Objective Field: | Climate change mitigation strategies |
UTAS Author: | Bach, LT (Dr Lennart Bach) |
ID Code: | 136057 |
Year Published: | 2019 |
Deposited By: | Ecology and Biodiversity |
Deposited On: | 2019-11-28 |
Last Modified: | 2019-12-12 |
Downloads: | 7 View Download Statistics |
Repository Staff Only: item control page