The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations The objective of the IPCC is to provide governments with scientific information they can use to develop climate policies. IPCC reports provide summaries of what is known to date about the drivers, impacts and risks associated with climate change, and how adaptation and mitigation can reduce those risks. Unfortunately, these reports are written in a highly technical style appropriate for specialists and are not an easy read for the rest of us. In other words, the IPCC reports can be a real slog to get through. The IPCC really should release parallel reports for the layperson. In lieu of that, I will occasionally post bits and pieces of reports that I’ve found especially interesting or useful.
This is the fourth (and last) post in a series based on the 2018 IPCC report, “Mitigation pathways compatible with 1.5°C in the context of sustainable development” - specifically, a multi-page table listing 70 measures that have been represented in the mitigation pathway literature. This post covers carbon dioxide (CO2) removal and other mitigation measures, starting with some definitions, care of the IPCC glossary (unless otherwise indicated):
Climate Change Mitigation: Human intervention to reduce emissions or enhance the sinks of greenhouse gases.
Sink: The United Nations Framework Convention on Climate Change (UNFCCC) refers to a sink as any process, activity or mechanism which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere.
Bioenergy with carbon dioxide capture and storage (BECCS): Carbon dioxide capture and storage (CCS) technology applied to a bioenergy facility.
Carbon dioxide capture and storage (CCS): A process in which a relatively pure stream of carbon dioxide (CO2) from industrial and energy-related sources is separated (captured), conditioned, compressed and transported to a storage location for long-term isolation from the atmosphere.
Direct air carbon dioxide capture and storage (DACCS): Chemical process by which CO2 is captured directly from the ambient air, with subsequent storage.
Enhanced weathering: Enhancing the removal of carbon dioxide (CO2) from the atmosphere through dissolution of silicate and carbonate rocks by grinding these minerals to small particles and actively applying them to soils, coasts or oceans.
Afforestation: Planting of new forests on lands that historically have not contained forests.
Biochar: Stable, carbon-rich material produced by heating biomass in an oxygen-limited environment. Biochar may be added to soils to improve soil functions and to reduce greenhouse gas emissions from biomass and soils, and for carbon sequestration.
Carbon dioxide capture and utilisation (CCU): process in which CO2 is captured and then used to produce a new product.
Ocean fertilization: Deliberate increase of nutrient supply to the near-surface ocean in order to enhance biological production through which additional carbon dioxide (CO2) from the atmosphere is sequestered. This can be achieved by the addition of micro-nutrients or macro-nutrients.
Ocean alcalinization (also spelled alkalinization): Chemical enhancement of ocean alkalinity to increase ocean carbon uptake (thereby reducing atmospheric CO2), and simultaneously reverses ocean acidification (Linton et al, 2018).
Photocatalysis: The utilization of solar energy to convert CO2 and other undesirable substances to renewable fuels or valuable chemicals (Fu, Yang, et al, 2019).
Halocarbons: A collective term for the group of partially halogenated organic compounds, such as the chlorofluorocarbons and hydrofluorocarbons. Many of the halocarbons have large global warming potentials. The chlorine and bromine-containing halocarbons are also involved in the depletion of the ozone layer.
Okay, now for carbon dioxide removal measures:
Source: Table 2.SM.6 (Section)/2018: Mitigation Pathways Compatible with 1.5°C in the Context of Sustainable Development Supplementary Material. In: Global Warming of 1.5°C. An IPCC Special Report https://www.ipcc.ch/sr15 Accessed February 8, 2020
Plus, measures that don’t fit into the other categories:
Source: Table 2.SM.6 (Section)/2018: Mitigation Pathways Compatible with 1.5°C in the Context of Sustainable Development Supplementary Material. In: Global Warming of 1.5°C. An IPCC Special Report https://www.ipcc.ch/sr15 Accessed February 8, 2020
Note that I’m not endorsing some measures over others. None of the above measures are mature technologies (meaning their path to optimality remains strewn with knowledge gaps) and none should be excluded from consideration. As energy systems engineer and Princeton professor Jesse Jenkins put it:
“If we’re really in a ‘climate crisis,’ then you go to war with your full arsenal, you don’t hold anything back. And you don’t purposefully make this crisis harder by limiting our already limited options.”
—
References:
Forster, P., D. Huppmann, E. Kriegler, L. Mundaca, C. Smith, J. Rogelj, and R. Seferian, 2018: Mitigation Pathways Compatible with 1.5°C in the Context of Sustainable Development Supplementary Material. In: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. Portner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Pean, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. Waterfield (eds.)]. Available from https://www.ipcc.ch/sr15
Fu, Z., Q. Yang, et al. (2019). "Photocatalytic conversion of carbon dioxide: From products to design the catalysts." Journal of CO2 Utilization 34: 63-73.
Lenton, A., Matear, R. J., Keller, D. P., Scott, V., and Vaughan, N. E.: Assessing carbon dioxide removal through global and regional ocean alkalinization under high and low emission pathways, Earth Syst. Dynam., 9, 339–357, https://doi.org/10.5194/esd-9-339-2018, 2018.
Rogelj, J., D. Shindell, K. Jiang, S. Fifita, P. Forster, V. Ginzburg, C. Handa, H. Kheshgi, S. Kobayashi, E. Kriegler, L. Mundaca, R. Séférian, and M.V. Vilariño, 2018: Mitigation Pathways Compatible with 1.5°C in the Context of Sustainable Development. In: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. Waterfield (eds.)]. In Press. https://www.ipcc.ch/sr15/chapter/chapter-2/