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.

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

EIA’s International Energy Outlook 2021 (IEO2021) Reference case projects that if current policy and technology trends continue, global energy consumption and energy-related CO₂ emissions will increase from 2020 through 2050 as a result of population and economic growth. However, projected future growth in energy-related CO₂ emissions is not evenly distributed across the world, and most of the projected future growth in energy-related CO₂ emissions is among the nonmember countries of the Organization for Economic Cooperation and Development (OECD).

¹ Only energy-related CO₂ emissions are considered in the projections, which does not cover the full nationally determined contribution (NDC) scope. 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 purpose of the IEO 2021 combination cases was to explore a wider range of outcomes. The IEO 2021 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: August 22, 2023.