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Energy and the environment explained Outlook for future emissions

Energy-related CO2 emissions could fall 25% to 38% below 2005 levels by 2030

The Annual Energy Outlook 2023 (AEO2023) includes projections for U.S. energy-related CO2 emissions in different cases.1 The AEO2023 projects lower energy-related CO2 emissions in 2030 relative to 2005 in the Reference case and all side cases. CO2 emissions are most sensitive to assumptions about economic growth and the cost of zero-carbon generation technology. Combinations of these two sets of assumptions form the high and low projections for energy-related CO2 emissions. Energy-related CO2 emissions decrease by 25% in 2030 relative to 2005 under assumptions for high economic growth and high zero-carbon technology costs and by as much as 38% under assumptions for low economic growth and low zero-carbon technology costs. Both of these AEO2023 side cases hinge on specific assumptions regarding the relationship between economic growth and zero-carbon technology development.2 In the High Economic Growth case, emissions fall initially and then begin to increase again in 2040 as industrial activity and travel (measured in vehicle miles traveled) increase, surpassing emissions reductions from the electric power sector.

Line graph showing projected U.S. energy-related carbon dioxide emissions in different cases of the U.S. Energy Information Administration's Annual Energy Outlook 2023.

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The largest variations in projected U.S. energy-related CO2 emissions across cases occur in the electric power, transportation, and industrial sectors. Although economic growth assumptions affect consumption and, in turn, projected CO2 emissions in all sectors, different case-specific assumptions affect sectors differently. For example, emissions from the electric power sector are particularly responsive to assumptions about the cost of zero-carbon technologies, and transportation sector emissions are sensitive to assumptions about fossil fuel supply and cost, particularly oil and petroleum products.

World CO2 emissions are projected to increase

The future trajectory of global energy consumption and energy-related CO2 emissions will be determined by complex and interrelated dynamics that play out across regions, sectors, and time. In the International Energy Outlook 2023 (IEO2023), EIA projects that global energy consumption increases 34% in the Reference case, from 638 quadrillion British thermal units (quads) in 2022 to 855 quads in 2050. Among the side cases, global energy consumption rises from 638 quads to between 739 quads and 999 quads by 2050. Corresponding energy-related CO2 emissions rise 15% in the Reference case, from 35.7 billion metric tons in 2022 to 41.0 billion metric tons in 2050. Among the side cases, they vary between 35.1 billion metric tons (a decrease from 2022) and 47.9 billion metric tons by 2050.

1 The AEO projections only consider energy-related CO2 emissions, which are only part of the full economy-wide emissions targets outlined in the U.S. nationally determined contribution (NDC) to global greenhouse gas reductions. The NDC is a formal submission to the United Nations Framework Convention on Climate Change. The United States submitted: "To achieve an economy-wide target of reducing its net greenhouse gas emissions by 50-52 percent below 2005 levels in 2030.”
2 The AEO 2023 combination cases explore a wider range of outcomes. The AEO 2023 did not explicitly consider the correlation or interaction between zero-carbon technology costs and economic growth. The High Economic Growth and High Zero-Carbon Technology Cost case assume this higher growth rate takes place without declining zero-carbon technology costs. Similarly, slower economic growth accompanies declining technology costs in the Low Economic Growth and Low Zero-Carbon Technology Cost case.

Last updated: October 27, 2023.