Energy and Climate Change

Energy production and use is the largest source of global greenhouse-gas (GHG) emissions. As a result, the World Energy Outlook (WEO) has, for many years, assessed the impact of energy sector policies and other developments on the projected path of GHG emissions, and the implications for meeting the world’s agreed climate goal. Each year, the WEO has presented a 450 Scenario that sets out a pathway for the energy sector that is consistent with having a 50% chance of limiting the global temperature increase to less than two degrees Celsius (°C). The latest assessment of our energy-related and process-related GHG emissions (as presented in WEO-2015) shows that the emissions gap to a two degrees trajectory in the Current Policies Scenario in 2030 is 16 gigatonnes of carbon dioxide equivalents (Gt CO2-eq) and 12 Gt CO2-eq in the case of the New Policies Scenario (Table 1).

Table 1 - Global energy- and process-related greenhouse-gas emissions by scenario (Gt CO2-eq)Table 1 - Energy and climate change (2015)

Assessment of climate pledges ahead of COP21

The WEO released a Special Report on Energy and Climate Change in June 2015, and a related Special Briefing for COP21 in October 2015. Building on the June report, the Special Briefing assesses the impact of climate actions, so called Intended Nationally Determined Contributions (INDCs), on energy demand, supply, emissions and investment trends through to 2030. The IEA’s World Energy Model was used to analyse the INDCs, with the same economic and energy price assumptions as in WEO-2015. The analysis is based upon the full implementation of unconditional INDC pledges, while also taking into account domestic energy sector policies that are currently in place or under discussion across all countries (it equally takes into account the latest data on energy use in China).  Total GHG emissions have been assessed using the global warming potentials from the Intergovernmental Panel on Climate Change’s (IPCC) Fifth Assessment Report.

Table 2 - Global greenhouse-gas emissions in the INDC Scenario (Gt CO2-eq)
Table 2 - Energy and climate change 2015

Notes: There is large uncertainty about current emissions from land use, land use change and forestry (LULUCF). For example, the IPCC’s Fifth Assessment Report states an emissions level for LULUCF of 5.4 Gt CO2 in 2010, while the Food and Agriculture Organization (FAO) reports 2.4 Gt in 2010. For the assessment of current LULUCF emissions, the WEO analysis combined data from FAO with national estimates, where available, which yields an emissions level of 1.0 Gt CO2 in 2010. Non-energy related non-CO2 GHG emissions were assessed with the OECD ENV-Linkages model and updated with national sources, if available, and with data from the US Environmental Protection Agency (US EPA) for fluorinated gases (F-gases).

If climate ambition is not raised progressively, it is estimated that the path set by the INDCs leads to GHG emissions in 2100 of around 38 Gt CO2-eq. Such a pathway is consistent with an average global temperature increase of around 2.7 °C by 2100, and around 3.5 °C in the long term (i.e. after 2200). To assess the impact on average global temperature, MAGICC has been used, with a post-2050 emissions pathway in-between the representative concentration pathways (RCP) 4.5 and RCP 6 scenarios from the IPCC’s Fifth Assessment Report, as this was judged as the long-term emissions trajectory most closely aligned with IEA’s INDC Scenario.

The bridge to a two degree pathway

WEO analysis indicates that the actions taken in the INDC Scenario are not sufficient to steer the energy system onto a pathway consistent with the world’s 2 °C climate goal. The IEA has therefore proposed the Bridge Scenario in the Special Report on Energy and Climate Change, which suggests how INDCs could be enhanced by a series of immediately practicable steps. The Bridge Scenario proposes a set of actions, drawing only on known technologies and policy measures which are tried and tested, which can raise climate ambition and help keep the door to a 2 °C pathway open. The Bridge Scenario leads to a peak in energy-related GHG emissions around 2020. The proposed measures are:

  • Increasing energy efficiency in the industry, buildings and transport sectors 
  • Progressively reducing the use of the least-efficient coal-fired power plants and banning their construction 
  • Increasing investment in renewable energy technologies in the power sector to reach $400 billion in 2030
  • Gradually phasing out fossil-fuel subsidies to end-users by 2030
  • Reducing the methane emissions arising from oil and gas production

Our work on WEO

Recent Reports

  • World Energy Outlook 2017
    Energy demand and supply projections to 2040 based on different scenarios
  • Energy Access Outlook 2017: From Poverty to Prosperity

    Published: 19 October 2017

    Energy is essential for humanity to develop and thrive. In 2015, the new Sustainable Development Goals, adopted by 193 countries, included for the first time a target to ensure affordable, reliable, sustainable and modern energy for all, underscoring a new level of political agreement on the importance of access to modern energy services. At the same time, the declining cost of decentralised renewables, increased access to affordable energy-efficientt appliances and the use of mobile platforms are changing the way we think about providing energy access. It is against this backdrop that the IEA produced this Special Report, part of its flagship World Energy Outlook (WEO) series.

    Southeast Asia Energy Outlook 2017

    Published: 24 October 2017

    The ten Association of Southeast Asian Nations (ASEAN) countries are among the most dynamic parts of the global energy system and a rising force in international energy affairs. Thanks to its growing partnership with Southeast Asia, the International Energy Agency (IEA) has conducted regular in-depth studies of the energy challenges facing this region. This new report, which was prepared as part of the IEA’s flagship World Energy Outlook series, provides insights for policy makers, industry and other energy stakeholders to help address the energy sector challenges facing Southeast Asia today.
    The report highlights:
    - The state of play across the Southeast Asia’s energy sector, based on the latest data and announcements
    - How today’s policies shape this region’s energy demand and supply outlook to 2040, and the implications for energy security, the environment and development
    - The opportunities that broader changes in global markets and low-carbon technologies open up for Southeast Asia
    - The investment required to improve efficiency and expand energy supply infrastructure, especially in the electricity sector
    - The mix of fuels and technologies that can help Southeast Asia achieve universal electricity access
    - An alternative pathway, the Sustainable Development Scenario, to meet energy security and environmental goals

  • World Energy Outlook 2016
    Energy demand and supply projections to 2040 based on different scenarios
  • World Energy Outlook 2016: Special focus on Renewable Energy

    Renewable energy is at the heart of the effort to transform the energy system to make it less carbon intensive, sustainable and compatible with the internationally adopted climate goals. The following three chapters focus on renewable energy, addressing many of the key questions. How fast is it expanding? Does it need to grow even faster? Are renewables competitive today? If not, when? What roles will policy-makers need to play? Can variable renewables be successfully integrated into the electricity system at the scale required?

    World Energy Outlook 2016: Energy and Air Pollution

    • Around 6.5 million premature deaths each year can be attributed to air pollution
    • Energy production and use are by far the largest man-made sources of air pollutants
    • Technologies to tackle air pollution are well known

    Clean air is vital for good health. Yet despite growing recognition of this imperative, the problem of air pollution is far from solved in many countries, and the global health impacts risk intensifying in the decades to come.

    The scale of the public health crisis caused by air pollution and the importance of the energy sector to its resolution are the reasons why the IEA is focusing on this critical topic for the first time.

    Based on new data for pollutant emissions in 2015 and projections to 2040, this special report, the latest in the World Energy Outlook series, provides a global outlook for energy and air pollution as well as detailed profiles of key countries and regions: the United States, Mexico, the European Union, China, India, Southeast Asia and Africa.

    In a Clean Air Scenario, the report proposes a pragmatic and attainable strategy to reconcile the world’s energy requirements with its need for cleaner air. Alongside the multiple benefits to human health, this strategy shows that resolving the world’s air pollution problem can go hand-in-hand with progress towards other environmental and development goals.

    World Energy Outlook 2016: Water-Energy Nexus Excerpt

    This excerpt from the World Energy Outlook 2016 looks at the critical interplay between water and energy, with an emphasis on the stress points that arise as the linkages between these two sectors intensify. The analysis assesses the current and future freshwater requirements for energy production, highlighting potential vulnerabilities and key stress points. 

    In addition, for the first time, the World Energy Outlook looks at the energy-for-water relationship, providing a first systematic global estimate of the energy requirements for different processes in the water sector, including water supply, wastewater treatment and desalination.

    Download Water-Energy Nexus in EPUB format

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