The ICJ’s Historic Advisory Opinion: A New Era for Climate Justice?
25 August 2025
Podcast: Intergenerational Justice and Germany’s Climate Policy Failures
26 August 2025
By Joaquín Gosalvez CASTILLO
While global GHG emissions have kept increasing after the pandemics[i][ii], the UN Secretary General, Antonio Guterres, has pointed that they “must decrease by 45 per cent by 2030”[iii][iv] to keep the 1,5-degree target alive. The world’s current inability to comply with the Paris Agreement challenges the logic of our energy transition model. Indeed, mitigation policies are based on energy efficiency, which involves using technology that requires less energy to perform the same function. Yet, with the 1970s oil crisis, two key pillars for energy security emerged[v]: conservation and efficiency. Nowadays, sufficiency, integrating energy conservation, has been defined in the latest IPCC report as “a set of measures and daily practices that avoid demand for energy, materials, land and water while delivering human well-being for all within planetary boundaries”[vi]. Thus, to what extent is it key to include a sufficiency approach in the IPCC reports to effectively tackle climate change and reach climate neutrality?
Firstly, efficiency alone will not be enough. Although efficiency measures in the last two decades have prevented 12% more energy use in 2017 and they can lead to more than 40% of the emissions cuts needed to fulfil the Paris Agreement[vii], these figures also show that the reduction has been too slow. Indeed, the constant increase in energy demand, partly due to a rebound effect[viii][ix], has erased all the efficiency gains as the IEA recognizes in the graph below[x][xi]. Another key issue for efficiency policies (electrification, renewable energy rollout) is the availability of critical minerals[xii], both in terms of reserves[xiii][xiv][xv], and of resilience of supply chains in the face of geopolitical tensions[xvi].
Total mineral demand for clean energy technologies by scenario, 2020 compared to 2040 (IEA, 2021).
Now the sufficiency approach should be systematized to enable further reductions while ensuring human well-being. The IPCC can inspire governments by pushing the Avoid, Shift and Improve logic[xx], and focusing on the materialization of a circular economy[xxi][xxii], based on reducing, recycling and reusing. It can follow the example of the NGO négaWatt which shows the potential of sufficiency policies with proposals, building on the first Plan de sobriété énergétique announced by the French Government, enabling to save 10% of energy consumption in two years[xxiii]. Limiting heating temperature to 19ºC, improving insulation, installing water-saving devices, among other measures, could reduce 30% gas and 36% fuel oil consumption in the buildings sector. In the transport sector, only three measures, as 110 km/h speed-limit in highways, would lead to a 3,6% energy demand reduction.
In conclusion, it is necessary to integrate an ambitious sufficiency approach in IPCC technical reports and models, and hence in its resulting SPMs, to help promote sufficiency plans globally. This is crucial to meet our climate goals.
[i] Ritchie, H., Roser, M., & Rosado, P. (2020, May 11). Greenhouse gas emissions. Our World in Data.
[ii] IEA. (2023, March 2). Global CO2 Emissions Rose less than initially feared in 2022 as clean energy growth offset much of the impact of greater coal and oil use. IEA.
[iii] UN News. (2022, April 27). Warning global emissions must shrink 45 per cent by 2030, secretary-general tells non-state expert group world cannot afford slow movers, greenwashing. United Nations.
[iv] UN News. (2021, September 17). Paris climate deal could go up in smoke without action: Guterres. United Nations.
[v] Bertoldi, P. (2022). Policies for Energy Conservation and sufficiency: Review of existing policies and recommendations for new and effective policies in OECD countries. Energy and Buildings, 264, 112075.
[vi] IPCC. (2022). Climate change 2022: Mitigation of climate change. Intergovernmental Panel on Climate Change.
[vii] IEA. (2018, October). Energy efficiency 2018 – analysis and outlooks to 2040. International Energy Agency.
[viii] Stutz, J. (2014, April 16). Quantifying sufficiency. Tellus Institute.
[ix] Lebot, B., Bertoldi, P., & Harrington, P. (n.d.). Consumption versus efficiency: Have we designed the right policies and programmes? American Council for an Energy-Efficient Economy.
[x] IEA. (2018, October). Energy efficiency 2018 – analysis and outlooks to 2040. International Energy Agency.
[xi] N.B. : Unit of the graph is TJ.
[xii] IEA (2021), The Role of Critical Minerals in Clean Energy Transitions, OECD Publishing, Paris.
[xiii] Lee, L. Y., & Glynn, J. (2023, March 14). Critical minerals: Will there be enough to meet the 2050 net-zero emissions target? Energy Post.
[xiv] OECD. (2022, May 9). Minerals critical to the Energy Transition. OECD.
[xv] Wang, S., Hausfather, Z., Davis, S., Lloyd, J., Olson, E. B., Liebermann, L., Núñez-Mujica, G. D., & McBride, J. (2023, January 27). Future demand for electricity generation materials under different climate mitigation scenarios. Joule.
[xvi] Osaka, S. (2023, February 2). Minerals are crucial for electric cars and wind turbines. Some worry whether we have enough. The Washington Post.
[xvii] See figure SPM.7 and SPM.8.
[xviii] See figure SPM.6.
[xix] IPCC. (2022, April 4). The evidence is clear: The time for action is now. We can halve emissions by 2030. IPCC.
[xx] Parrique, T. (2022, April 24). Sufficiency means degrowth. Timothée Parrique.
[xxi] Bocken, N. & Short, S. (2019). Transforming Business Models: Towards a Sufficiency-based Circular Economy.
[xxii] Jungell-Michelsson, J., & Heikkurinen, P. (2022). Sufficiency: A systematic literature review, Ecological Economics, Volume 195, 107380, ISSN 0921-8009.
[xxiii] Sobriété: Négawatt Présente SES propositions chiffrées. (2022, September 29). Association négaWatt.
References
Bocken, N. & Short, S. (2019). Transforming Business Models: Towards a Sufficiency-based Circular Economy.
IEA (2021), The Role of Critical Minerals in Clean Energy Transitions, OECD Publishing, Paris, https://doi.org/10.1787/f262b91c-en.
IEA. (2018, October). Energy efficiency 2018 – analysis and outlooks to 2040. International Energy Agency. Retrieved April 16, 2023, from https://www.iea.org/reports/energy-efficiency-2018
IEA. (2023, March 2). Global CO2 Emissions Rose less than initially feared in 2022 as clean energy growth offset much of the impact of greater coal and oil use. IEA. Retrieved April 16, 2023, from https://www.iea.org/news/global-co2-emissions-rose-less-than-initially-feared-in-2022-as-clean-energy-growth-offset-much-of-the-impact-of-greater-coal-and-oil-use
IPCC. (2022). Climate change 2022: Mitigation of climate change. Intergovernmental Panel on Climate Change. Retrieved April 16, 2023, from https://www.ipcc.ch/report/ar6/wg3/
IPCC. (2022, April 4). The evidence is clear: The time for action is now. We can halve emissions by 2030. IPCC. Retrieved April 16, 2023, from https://www.ipcc.ch/2022/04/04/ipcc-ar6-wgiii-pressrelease/
Jungell-Michelsson, J., & Heikkurinen, P. (2022). Sufficiency: A systematic literature review, Ecological Economics, Volume 195, 107380, ISSN 0921-8009, https://doi.org/10.1016/j.ecolecon.2022.107380.
La préfecture et les services de l’État en région Nouvelle-Aquitaine. (2022, December 2). Dossiers : Sobriété énergétique. Les 15 mesures du plan de sobriété. Retrieved April 16, 2023, from https://www.prefectures-regions.gouv.fr/nouvelle-aquitaine/Grands-dossiers/Sobriete-energetique/Les-15-mesures-du-plan-de-sobriete#:~:text=%C3%89teindre%20les%20lumi%C3%A8res%20%C3%A0%20certaines,entre%204%20et%206%20ans
Lebot, B., Bertoldi, P., & Harrington, P. (n.d.). Consumption versus efficiency: Have we designed the right policies and programmes? American Council for an Energy-Efficient Economy. Retrieved April 16, 2023, from https://www.aceee.org/files/proceedings/2004/data/papers/SS04_Panel7_Paper18.pdf
Lee, L. Y., & Glynn, J. (2023, March 14). Critical minerals: Will there be enough to meet the 2050 net-zero emissions target? Energy Post. Retrieved April 16, 2023, from https://energypost.eu/critical-minerals-will-there-be-enough-to-meet-the-2050-net-zero-emissions-target/
OECD. (2022, May 9). Minerals critical to the Energy Transition. OECD. Retrieved April 16, 2023, from https://www.oecd.org/coronavirus/en/data-insights/minerals-critical-to-the-energy-transition
Osaka, S. (2023, February 2). Minerals are crucial for electric cars and wind turbines. Some worry whether we have enough. The Washington Post. Retrieved April 16, 2023, from https://www.washingtonpost.com/climate-environment/2023/02/02/critical-minerals-run-out-shortage/
Bertoldi, P. (2022). Policies for Energy Conservation and sufficiency: Review of existing policies and recommendations for new and effective policies in OECD countries. Energy and Buildings, 264, 112075. https://doi.org/10.1016/j.enbuild.2022.112075
Parrique, T. (2022, April 24). Sufficiency means degrowth. Timothée Parrique. Retrieved April 16, 2023, from https://timotheeparrique.com/sufficiency-means-degrowth/
Ritchie, H., Roser, M., & Rosado, P. (2020, May 11). Greenhouse gas emissions. Our World in Data. Retrieved April 16, 2023, from https://ourworldindata.org/greenhouse-gas-emissions
Sobriété: Négawatt présente ses propositions chiffrées. (2022, September 29). Association négaWatt. Retrieved April 16, 2023, from https://www.negawatt.org/sobriete-propositions-chiffrees
Stutz, J. (2014, April 16). Quantifying sufficiency. Tellus Institute. Retrieved April 16, 2023, from https://www.tellus.org/tellus/publication/quantifying-sufficiency
UN News. (2021, September 17). Paris climate deal could go up in smoke without action: Guterres. United Nations. Retrieved April 16, 2023, from https://news.un.org/en/story/2021/09/1100242
UN News. (2022, April 27). Warning global emissions must shrink 45 per cent by 2030, secretary-general tells non-state expert group world cannot afford slow movers, greenwashing. United Nations. Retrieved April 16, 2023, from https://press.un.org/en/2022/sgsm21250.doc.htm
Wang, S., Hausfather, Z., Davis, S., Lloyd, J., Olson, E. B., Liebermann, L., Núñez-Mujica, G. D., & McBride, J. (2023, January 27). Future demand for electricity generation materials under different climate mitigation scenarios. Joule. Retrieved April 16, 2023, from https://www.cell.com/joule/fulltext/S2542-4351(23)00001-6?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2542435123000016%3Fshowall%3Dtrue