Scenarios in the World Energy Outlook 2025

In 2021, the IEA was asked by the COP26 Presidency to give an indication of what achieving the 1.5 °C goal would mean for the energy sector. The NZE Scenario, which responded to this request, represents a global pathway for the energy sector towards the goal of limiting warming to 1.5 °C. It describes a pathway to reducing global energy-related carbon dioxide (CO2) emissions to net zero by 2050, alongside achieving goals on universal energy access and large reductions in air pollution. It does this while recognising that there are various paths to reaching these objectives and that each country will have its own route.

The NZE Scenario has been updated in the WEO every year since 2021. Because of the delay in reducing emissions, each successive update factors in higher cumulative emissions and higher peak warming. In the WEO-2024 version of the NZE Scenario, peak warming reached just below 1.6 °C around 2040 before subsequently declining to below 1.5 °C by 2100.

The level of long-term warming today stands at around 1.4 °C. Based on the latest trends of technology deployment, sector by sector - including slower improvements in efficiency and electrification of some end-uses, and lower deployment of hydrogen and carbon capture, utilisation and storage (CCUS) - the nearer-term emissions trajectory for the NZE Scenario in the WEO-2025 has again been revised upwards. At the same time, the goal of net zero emissions by 2050 is retained in the scenario design.

As countries prepare to consider the next round nationally determined contributions under the Paris Agreement, the updated NZE Scenario pathway provides an overview of what would it take to keep alive the possibility of limiting the rise in global average temperatures to 1.5 °C, taking into account recent data on energy, technology, investment and emissions.