skip to content

Cambridge Institute for Sustainability Leadership (CISL)

Phasing out fossil fuels

Climate change is a threat to human well-being, planetary health and long-term economic prosperity. Human activities, principally through emissions of greenhouse gases (GHGs) such as CO2, have unequivocally caused global warming, with global surface temperature by 2020 reaching approximately 1.1°C above pre-industrial levels.

Continued greenhouse gas emissions will lead to increasing global warming. Every increment of global warming will intensify multiple and concurrent hazards.

There is a rapidly closing window of opportunity to secure a liveable and sustainable future for all. What’s more, the costs of action are lower, and the benefits arrive quicker the more quickly we act. The choices and actions implemented in this decade will have impacts now and for the distant future.

The Paris Agreement is a global, legally binding agreement, to hold the increase in the global average temperature to well below 2°C above pre-industrial levels and pursue efforts to limit the temperature increase to 1.5°C. There is broad consensus that, to limit global warming to these levels, global greenhouse gas emissions must peak before 2025 at the latest, decline 43 per cent by 2030 and reach net zero by mid-century. For some advanced economies, swifter transition is both necessary (to enable achievement of global goals) and explicitly adopted as a goal.

The latest IPCC findings, including their assessment of the challenges facing large scale deployment of Carbon Capture and Storage (CCS), clearly indicate that the achievement of the Paris Agreement will require a dramatic cut in the use of fossil fuels. Starting immediately, with sustained and deep reductions over the coming decades. This will require phasing out the vast majority of fossil fuel use by 2050, and scaling up technology to capture the emissions of residual fossil fuel use. Even to achieve weaker climate targets, such as limiting global average temperature increases to 2°C (which implies significantly increased climate impacts with consequent loss of life, destruction and collapse in natural systems), will still require significant reductions in fossil fuels over the same period.

There are, of course, significant complexities inherent in transition. Including, for example, issues relating to: energy security; global trade, financing mechanisms and economics; the challenge of sourcing the raw materials required to build new energy infrastructure; the lack of near-term viable and scalable alternatives for some industrial processes currently dependent on fossil fuels; and the need to address issues of social justice particularly in relation to the distribution of the costs and benefits of transition. In light of these complexities, there are significant live debates and tensions about transition pathways and timelines (eg replacing coal with gas as a transition fuel in countries heavily dependent on coal). The evidence and analysis provided by the IPCC is clear that we have no option but to find ways to navigate and resolve these challenges.

CISL’s work contributes to accelerating the transition to a net zero energy system in multiple ways and it is important that we have a consistent position and approach to decisions about who we work with and the nature and focus of our activities internationally, in support of transition.

Our approach is informed by the most up-to-date and robust evidence and analysis of current status and trends, as well as potential future risks and responses. It is also informed by insight from our work with businesses, governments, and financial institutions about what can practically be achieved in the near term in support of long-term goals, and our assessment about what CISL can most credibly and effectively do to accelerate progress. Based on that we support the following positions:

  • Any increase in global average temperature creates multiple and concurrent hazards - some of which pose existential risks to the economy and parts of society. Therefore, immediate and transformative action must be taken to limit further temperature increases.  Although it is looking increasingly challenging to limit global temperature increase to 1.5 degrees without overshoot, we believe that it is important to remain focused on this goal, because higher increases will have significant negative impacts for the global population and the natural systems on which we depend. With a 2°C increase the risks of extreme heat waves, droughts, water stress and extreme weather would be far greater. We therefore continue to focus on keeping warming within the 1.5 °C limit.
  • In order to limit global warming to 1.5 °C above pre-industrial levels, there is a need to phase out the vast majority of fossil fuel use by 2050. We recognise that the IPCC indicates the need for "transitioning from fossil fuels without abatement or ‘carbon capture and storage’ (CCS) to very low- or zero-carbon energy sources". The IEA net zero roadmap indicates that fossil fuels must "fall from almost four‐fifths of total energy supply in 2021 to slightly over one‐fifth by 2050”.
  • Projected CO2 emissions from existing fossil fuel infrastructure without significant additional abatement would exceed current global emission reduction goals. To deliver upon global emissions reductions goals we believe there is no scope for any new fossil fuel development. We believe that fossil fuel producers should therefore focus not on new exploration and development but on output – and emissions reductions – from the operation of existing assets, and on transitioning out of these assets on a timeline that is consistent with a 1.5°C trajectory.
  • Both the IPCC and the IEA acknowledge that fossil fuel abatement mechanisms, i.e. carbon capture and storage (CCS, carbon capture, use and storage – CCUS) are being deployed at levels below expectations. The IPCC notes that CCS (CCUS) “currently faces technological, economic, institutional, ecological, environmental and socio-cultural barriers. Currently, global rates of CCS deployment are far below those in modelled pathways limiting global warming to 1.5°C to 2°C.” We believe that the potential for widescale deployment of CCS/CCUS should not be used to delay significant cuts to fossil fuel use over the next decade. These solutions should be prioritised for neutralising the hardest to abate carbon emissions and for achieving a net negative emissions economy in the latter half of this century.
  • To slow warming we must not only work ever more urgently on cutting CO2 but also focus on the shorter lived, far more potent greenhouse gases such as methane.  The IEA 2022 progress tracker noted that, although there is a need to reduce Fugitive Methane Emissions(FMEs)1 associated with fossil fuels by 75% by 2030, and effective policy tools exist to achieve this outcome, FMEs continue to increase. There is a need for urgent action to stop fugitive methane emissions.
  • The current strategies and development pipelines of the fossil fuel sector (across national, state owned and major private enterprises) are not consistent with global emission reduction targets. In addition, public and private finance flows for fossil fuels are still greater than those for climate adaptation and mitigation. There is therefore an urgent need for government action to drive the transition away from fossil fuels. As highlighted by the IEA, this includes fossil fuel subsidy phaseouts, carbon pricing and other market reforms to ensure appropriate price signals. Policies should limit or provide disincentives for the use of certain fuels and technologies, such as unabated coal- fired power stations.
  • A socially just transition is possible and feasible. Informed by IPCC analysis, we believe that, with effective long-term policy, innovation, collaboration and investment, it will be possible to achieve the sustainable development goals (including eradicating extreme poverty, energy poverty and providing decent living standards) in low emitting countries in the near term without significant emissions growth, and without a dependence on expansion of unabated fossil fuel production. Global and European energy transition scenarios and analysis indicate that it is possible and economically viable to achieve transition in line with global climate goals, and that the transition would deliver multiple additional social, economic and environmental benefits.

CISL’s position is informed by:

1. The latest synthesis report by the Intergovernmental Panel on Climate Change (IPCC)

2. The Paris Agreement, an international treaty on climate change

3. Work by the International Energy Agency on:

  • A roadmap for how to transition to a net zero energy system by 2050 while ensuring stable and affordable energy supplies, providing universal energy access, and enabling robust economic growth.
  • A net zero by 2050 scenario for the energy sector
  • Tracking progress against this scenario for 55 components of the energy system that are critical for clean energy transitions.

4. Analysis undertaken by the Fossil Fuel Registry, an open, transparent repository of data on fossil fuel production worldwide, expressed in terms of its embedded carbon dioxide emissions

This position is not intended as a comprehensive overview of energy transition, but specifically to outline CISL’s position on fossil fuel phase out and engagement with fossil fuel companies.

Read more about our work to drive a net zero economy


1 Fugitive methane emissions occur from leakages that are not intended, for example because of a faulty seal or leaking valve (IEA)