【Report】IPCC Synthesis Report emphasizes importance of fossil fuel phase-out

On 20 March 2023, the Intergovernmental Panel on Climate Change (IPCC) released its AR6 Synthesis Report. This article summarizes the findings and conclusions related to coal-fired power generation.

Global warming: Causes, effects, adaptation, and mitigation

In the AR6’s Section A. Current Status and Trends, the IPCC notes that the primary cause of global warming is greenhouse gas emissions associated with human activities (Section A.1), and that the largest share and growth in gross GHG emissions were from CO2 from fossil fuel combustion and industrial processes, including coal-fired power generation (Section A.1.4).

  • Human activities, principally through emissions of greenhouse gasses, have unequivocally caused global warming, with global surface temperature reaching 1.1°C above 1850-1900 in 2011-2020. (A.1)
  • Global net anthropogenic GHG emissions have been estimated to be 59 ± 6.6 GtCO2-eq9 in 2019, about 12% (6.5 GtCO2-eq) higher than in 2010 and 54% (21 GtCO2-eq) higher than in 1990, with the largest share and growth in gross GHG emissions occurring in CO2 from fossil fuels combustion and industrial processes (CO2-FFI) followed by methane. (A.1.4)


The IPCC has pointed out that the effects of global warming are felt disproportionately (A.2). The IPCC also states that limits to adaptation to global warming have been reached in some ecosystems and regions (A.3), and that current emissions reductions efforts by countries around the world still make it difficult to limit global warming to below 2°C by the end of the century, with global temperature rise likely to exceed 1.5°C (A.4).

  • Vulnerable communities who have historically contributed the least to current climate change are disproportionately affected (high confidence). (A.2)
  • Hard and soft limits to adaptation have been reached in some ecosystems and regions. (A.3)
  • Global GHG emissions in 2030 implied by nationally determined contributions (NDCs) announced by October 2021 make it likely that warming will exceed 1.5°C during the 21st century and make it harder to limit warming below 2°C. (A.4)


Acceleration of global warming and effectiveness of countermeasures

On the effectiveness of global warming countermeasures, the IPCC notes in Section B. Future Climate Change, Risks, and Long-Term Responses that deep, rapid, and sustained reductions in greenhouse gas emissions can limit further global warming (B.1, B.3). However, it also notes that, with every increment of global warming, the risks of climate change will escalate (B.2) and adaptation options will become constrained and less effective (B.4), and it emphasizes the need for earlier implementation of measures.

  • Deep, rapid, and sustained reductions in greenhouse gas emissions would lead to a discernible slowdown in global warming within around two decades, and also to discernible changes in atmospheric composition within a few years (high confidence). (B.1)
  • Risks and projected adverse impacts and related losses and damages from climate change escalate with every increment of global warming (very high confidence). (B.2)
  • Some future changes are unavoidable and/or irreversible but can be limited by deep, rapid and sustained global greenhouse gas emissions reduction. (B.3)
  • Adaptation options that are feasible and effective today will become constrained and less effective with increasing global warming. With increasing global warming, losses and damages will increase and additional human and natural systems will reach adaptation limits.(B.4)


More specifically, the IPCC predicts that rapid and deep reductions in greenhouse gas emissions this decade will be necessary to limit global warming to 1.5°C or 2°C or less (B.5, B.6), and that if the existing fossil fuel infrastructure, including coal-fired power generation, is in use, projected CO2 emissions from these infrastructures would exceed the remaining global carbon budget for 1.5°C (B.5). It also noted that carbon capture and storage (CCS) technology, which the Japanese government is heavily promoting, is not as mature in the power sector (B.6.3 Note 47).

  • Cumulative carbon emissions until the time of reaching net zero CO2 emissions and the level of greenhouse gas emission reductions this decade largely determine whether warming can be limited to 1.5°C or 2°C (high confidence). (B.5)
  • Projected CO2 emissions from existing fossil fuel infrastructure without additional abatement would exceed the remaining carbon budget for 1.5°C (50%) (high confidence). (B.5)
  • All global modelled pathways that limit warming to 1.5°C (>50%) with no or limited overshoot, and those that limit warming to 2°C (>67%), involve rapid and deep and, in most cases, immediate greenhouse gas emissions reductions in all sectors this decade. (B.6)
  • In contrast to the oil and gas sector, CCS is less mature in the power sector, as well as in cement and chemicals production, where it is a critical mitigation option. (B.6.3, Footnote 47)


The report also notes that, even if warming exceeds 1.5°C (overshoot), it can be reduced again, but the impacts and risks increase with the magnitude and duration of the overshoot. (B.7)

  • If warming exceeds a specified level such as 1.5°C, it could gradually be reduced again by achieving and sustaining net negative global CO2 emissions. (B.7)
  • Overshoot entails adverse impacts, some irreversible, and additional risks for human and natural systems, all growing with the magnitude and duration of overshoot. (high confidence) (B.7)


Urgency and equity of global warming countermeasures

In the Section C. Urgency of Near-Term Integrated Climate Action the IPCC notes that countermeasures against global warming in this decade will have an impact on the future, and accelerating actions will mitigate the losses and damages caused by climate change. (C.1, C.2). However, it also points out that delaying mitigation and adaptation actions would increase losses and damages through stranded assets and cost-escalation for high-emissions infrastructure such as coal-fired power plants. (C.2)

  • Climate change is a threat to human well-being and planetary health (very high confidence). There is a rapidly closing window of opportunity to secure a liveable and sustainable future for all (very high confidence). (C.1)
  • The choices and actions implemented in this decade will have impacts now and for thousands of years (high confidence). (C.1)
  • Deep, rapid and sustained mitigation and accelerated implementation of adaptation actions in this decade would reduce projected losses and damages for humans and ecosystems (very high confidence), and deliver many co-benefits, especially for air quality and health (high confidence). (C.2)
  • Delayed mitigation and adaptation action would lock-in high-emissions infrastructure, raise risks of stranded assets and cost-escalation, reduce feasibility, and increase losses and damages (high confidence). (C.2)


The IPCC also calls for substantial reduction in overall fossil fuel use, minimal use of unabated fossil fuels, and use of carbon capture and storage (CCS) in the remaining fossil fuel systems. (C.3.2) In this context, emission reduction measures refers to “that substantially reduce the amount of GHG emissions throughout the life cycle”, and examples include capturing 90% or more CO2 from power plants, or 50–80% of fugitive methane emissions from energy supply. (C3.2, Footnote 51)  Therefore, in order to be recognized as emission reduction measures, some of the measures promoted by the Japanese government and power companies to extend the life of coal-fired power plants must first resolve a number of difficult issues.J-Power’s GENESIS Matsushima project, which aims to reduce emissions by adding gasification equipment to old coal-fired power plants with CCS to be implemented in the future, and JERA’s Hekinan Thermal Power Plant demonstration test, which will co-fire ammonia (the co-firing rate is 20% for the time being), must resolve issues preventing full CCS implementation, use of green (not grey) ammonia, and expansion of the rate of ammonia used in co-firing.

  • Net zero CO2 energy systems entail: a substantial reduction in overall fossil fuel use, minimal use of unabated fossil fuels, and use of carbon capture and storage in the remaining fossil fuel systems; electricity systems that emit no net CO2; widespread electrification; alternative energy carriers in applications less amenable to electrification; energy conservation and efficiency; and greater integration across the energy system (high confidence). (C.3.2)
  • In this context, ‘unabated fossil fuels’ refers to fossil fuels produced and used without interventions that substantially reduce the amount of GHG emitted throughout the life cycle; for example, capturing 90% or more CO2 from power plants, or 50–80% of fugitive methane emissions from energy supply. (C3.2, Footnote 51)


Furthermore, the IPCC has repeatedly pointed out the importance of equity in implementation of climate actions (C.4, C.5). In particular, it emphasizes the need for consideration of just transition principles in regions with a high dependency on fossil fuels. (C.4.1)

  • Accelerated and equitable action in mitigating and adapting to climate change impacts is critical to sustainable development. (C.4)
  • In regions with high dependency on fossil fuels for, among other things, revenue and employment generation, mitigating risk for sustainable development requires policies that promote economic and energy sector diversification and considerations of just transitions principles, processes and practices (high confidence).(C.4.1)
  • Prioritising equity, climate justice, social justice, inclusion and just transition processes can enable adaptation and ambitious mitigation actions and climate resilient development. (C.5)



In the AR6, the IPCC clearly states that rapid and significant reductions in greenhouse gas emissions over the next decade, especially from fossil fuel infrastructure, are essential if we and future generations are to reduce damage from the climate crisis in the future. Japan should seriously heed this warning from science and prioritize a phase-out of fossil fuels that takes into account just transition, rather than depending on overly hopeful expectations for reduction methods like CCS that still have numerous issues to overcome.

Related links

・IPCC:AR6 Synthesis Report: Climate Change 2023(Link


Written/Published by: IPCC(Intergovernmental Panel on Climate Change)
Published: March 20, 2023