Review of Estimates for GHG Emissions Mitigation Opportunities in theUnited States
Nonfederal leaders across the United States are stepping up to address climate change while promoting
economic growth, creating jobs, and improving public health. Already, over 2,700 states, cities, and businesses,
representing 159 million Americans, have committed to cutting greenhouse gas (GHG) emissions consistent withthe goals of the Paris Agreement. These nonfederal actors have enacted a wide diversity of measures to achieve
real reductions in emissions while driving economic growth, including cap-and-trade policies, renewable
portfolio standards, low-emission vehicle targets, and standards for oil and gas methane that are deliveringresults.
But these opportunities are nowhere near exhausted. Given the rapid pace of innovation and technologicalchange, there are significant opportunities to accelerate these trends in coming years.
Long-term low-GHG pathways are not only technologically feasible but are pro-growth compared to no-action
alternatives.1 A 2014 report by the White House Council of Economic Advisors found that failure to act on climate
could result in annual global damages equivalent to 2% of global output by the end of the century.2 And the costs
are likely to be negligible compared to the benefits of investing in the new economy, improving health throughcleaner air, and avoiding climate damages.3 An additional study found that the United States could achieve
reductions in the range of its 2025 target with near-negligible impacts on GDP growth (less than 0.05%).
This note summarizes recent research from diverse organizations that, taken together, paints a broad andconsistent picture of major, near-term opportunities for significant new climate action in the United States. Theseestimates indicate that more can be done, increasing optimism for a cleaner future.
In September 2018, building on these important insights, America’s Pledge co-chairs UN Special Envoy for Climate
Action Michael Bloomberg and California Governor Edmund G. Brown, Jr. will release a first-of-its-kind, bottomup, economy-wide analysis detailing the significant impact these actors are already having on the US emissions
trajectory, and detailing new opportunities for states, cities, and businesses to reduce emissions in the near term
while laying the foundation to achieve long-term climate goals.

Power Sector•

Driven by technological innovation, market demand, and policies, a rapid transition in the US electric sector isunderway.

•In many regions of the United States, it is now cheaper to build new wind and solar than new fossil generation.4
The United States is projected to install 60 gigawatts (GW) of solar capacity through 2022,5 and 60 GW of wind
through 2026.6 Given favorable market conditions and strong support for policies such as renewable portfolio
standards,7 states, cities, and businesses have driven significant growth in this area and have the opportunity
to set more ambitious renewable energy targets.

1•A Bloomberg New Energy Finance study found that half of all coal-fired power plants (roughly 150 GW) haverun at a net loss over the last six years.8 Coordinated support for phasing out these plants could yield
substantial benefits well before 2030.

Transportation•There is significant untapped potential in cleaner transportation, which is now the biggest source of GHG
emissions in the United States. While the Trump Administration is moving to dismantle fuel-economy and GHGstandards for cars and trucks, the EPA estimated in 2016 that existing cost-effective technologies could cut
emissions from vehicles sold between 2022 and 2025 by a cumulative 540 MMTCO2e over the lifetime of thosevehicles.9•Since 2016, nearly every forecast for electric vehicle (EV) growth has increased dramatically,10 as costs have
dropped and consumer demand has increased. Bloomberg New Energy Finance projects that 27 million EVs
will be on US roads by 2030 and will increase nearly fivefold to reach 119 million by 2040.11•The International Council on Clean Transportation estimates that US automakers could cut carbon emissions
from new vehicles in half by 2030 from 2016 levels.12•

Nonfederal actors can help boost this potential through vehicle mandates, subsidies, infrastructure, andgovernment procurement policies.

Building and Industrial Efficiency•

Energy efficiency is consistently reported as the lowest-cost emissions reduction strategy while helping
consumers save money on their energy bills.13•

An analysis found that new state-level consumer appliance standards could reduce US emissions by 23
MMTCO2e annually by 2035.14 With renewed federal action, this could reach 134 MMTCO2e in annual savingsby 2035.15•

Through policies promoting smart growth, building efficiency, and increased public transportation, US cities
could reduce emissions 210–480 MMTCO2e annually by 2035.16•

The US Department of Energy estimates that existing technology (not including advanced technology, carbon
capture and storage, or electrification) could cut energy demand in refining by 13% and in chemical production
by 20%.17

Oil and Gas—Methane•

Oil and gas operations are responsible for nearly 300 MMTCO2e of emissions annually in the United States butup to 45% of this—equivalent to removing 140 MMTCO2e by 203018—could be captured at low or no costthrough new policies, such as Colorado’s, requiring technology improvements and monitoring for leaks.

•Another analysis estimates that this potential could be as high as 200 MMTCO2e by 2030.19

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Hydrofluorocarbons•

Hydrofluorocarbons (HFCs) are potent greenhouse gases used in air conditioners, insulation, and flame
retardants. Expedited phase-out of these chemicals could result in 250 MMTCO2e of emissions reductions by
2030 at zero or low cost.20•States, cities, and businesses can support this phaseout by encouraging HFC recovery and destruction fromappliances prior to disposal and engaging with large retailers such as supermarkets on improved refrigeration
management.

Land-Sector Emissions•Agriculture and land use is a large source of methane, carbon, and nitrous oxide emissions but these emissions
can be mitigated with greater adoption of climate-smart agriculture that has substantial cobenefits to farmers
and rural communities.

•Adoption of no-till farming and planting cover crops can increase soil carbon sequestration while reducing
erosion and water pollution and increasing resilience to drought. One analysis found that agricultural nitrous
oxide emissions could be reduced by 24%, assuming reasonable implementation costs.21

Overall US Economy•Studies assessing the potential impact of new policies on overall US emissions vary significantly and depend
on what sectors and gases are covered in the analysis, as well as assumptions about technology costs andpolicy impacts.

•A recent peer-reviewed study compared 11 different models to understand the potential for reductions infossil fuel emissions.22 It reports an average potential reduction estimate of roughly 800–1,400 MMTCO2e per
year below current levels by 2025, and an upper-end potential estimate of roughly 1,600–2,600 MMTCO2e per
year below current levels by 2025.

•In September, America’s Pledge will release a roadmap and assessment of potential new ambition, including
actions that stem from states, cities, and businesses and that can reduce emissions across all major greenhousegases.

###1 The White House, “U.S. Midcentury Strategy for Deep Decarbonization,” (2016), online at: https://unfccc.int/files/focus/long-term_strategies/application/pdf/us_mid_century_strategy.pdf.
2 White House Council of Economic Advisers, “The Cost of Delaying Action to Stem Climate Change,” The White House (2014), online at:https://obamawhitehouse.archives.gov/sites/default/files/docs/the_cost_of_delaying_action_to_stem_climate_change.pdf.
3 Barron, Alexander R., Allen A. Fawcett, Marc A.C. Hafstead, James R. McFarland, and Adele C. Morris. "Policy Insights from the EMF 32 Study on U.S.
Carbon Tax Scenarios." Climate Change Economics 2018 09:01, DOI: https://doi.org/10.1142/S2010007818400031
4 Energy Information Administration, “Levelized Cost and Levelized Avoided Cost of New Generation Resources in the Annual Energy Outlook 2018,”
March 2018, online at: https://www.eia.gov/outlooks/aeo/pdf/electricity_generation.pdf.
Rhodes, Joshua D., et al., “A Geographically Resolved Method to Estimate Levelized Power Plant Costs with Environmental Externalities, (2016), online
at http://energy.utexas.edu/the-full-cost-of-electricity-fce/.

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5 Green Tech Media Research, “U.S. Solar Market Insight: 2017 Year in Review,” (2017), online at:https://www.greentechmedia.com/research/subscription/u-s-solar-market-insight#gs.ZfXAWzM.
6 Deign, Jason, “The Global Wind Market Enters a Period of Transition,” Green Tech Media, June 15, 2017, online at:https://www.greentechmedia.com/articles/read/the-global-wind-market-enters-a-period-of-transition#gs.rTQx524
7 Howe, Peter D., Matto Mildenberger, Jennifer R. Marlon, and Anthony Leiserowitz, “Geographic variation in opinions on climate change at state andlocal scales in the USA.” Nature Climate Change (2015), online at: https://www.nature.com/articles/nclimate2583.
8 Nelson, William, “Half of U.S. Coal Fleet on Shaky Economic Footing,” Bloomberg New Energy Finance, March 26, 2018.
9 Environmental Protection Agency, “Final Determination on the Appropriateness of the Model Year 2022-2025 Light-Duty Vehicle Greenhouse Gas
Emissions Standards under the Midterm Evaluation,” January 17, 2017, online at: https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100QQ91.pdf.
10 Lacey, Stephen, “Everyone is Revising Their Electric Vehicle Forecasts Upward – except automakers,” Green Tech Media, June 17, 2017, online at:https://www.greentechmedia.com/articles/read/everyone-is-revising-electric-vehicle-forecasts-upward#gs.lqyaixU.
11 Shankleman, Jess, “Big Oil just woke up to the threat of rising electric car demand,” Bloomberg, July 14, 2017, online at:https://www.bloomberg.com/news/articles/2017-07-14/big-oil-just-woke-up-to-the-threat-of-rising-electric-car-demand.
12 International Council on Clean Transportation, “Efficient Technology and Cost Assessment for U.S. 2025-2030 Light-Duty, Vehicles,” March 2017,
online at: https://www.theicct.org/sites/default/files/publications/US-LDV-tech-potential_ICCT_white-paper_22032017.pdf.
13 See, for example, Ian M Hoffman, Greg Leventis, Charles A Goldman, “Trends in the Program Administrator Cost of Saving Electricity for Utility
Customer-Funded Energy Efficiency Programs” Lawrence Berkeley National Laboratory report LBNL-1007009, January 2017, online at:https://emp.lbl.gov/publications/trends-program-administrator-cost
14 Mauer, Joanna, Andrew deLaski and Marianna DiMascio, “States Go First: How States Can Save Consumers Money, Reduce Energy and Water
Waste, and Protect the Environment with New Appliance Standards,” Appliance Standards Awareness Project, July 2017, online at: https://appliancestandards.org/sites/default/files/States%20Go%20First.pdf.
15 deLaski, Andrew, et al., “Next Generation Standards: how the National Energy Efficiency Standards Program Can Continue to Drive Energy, Economicand Environmental Benefits,” Appliance Standards Awareness Project (August 2016), online at: https://appliancestandards.org/sites/default/files/States%20Go%20First.pdf.
16 National Renewable Energy Laboratory, “Estimating the National Carbon Abatement Potential of City Policies: A Data Driven Approach,” October
2016, online at: https://www.nrel.gov/docs/fy17osti/67101.pdf.
17 Department of Energy Advanced Manufacturing Office Bandwidth Studies are available online here: https://www.energy.gov/eere/amo/energyanalysis-data-and-reports.
18 Environmental Protection Agency, “Mitigation of Non-CO2 Greenhouse Gases in the United States: 2010 to 2030,” April 2014, online at:https://www.epa.gov/sites/production/files/2016-07/documents/mac_report_2014-us_summ.compressed.pdf.
19 Rhodium Group, “Untapped Potential: Reducing Global Methane Emissions from Oil and Natural Gas Systems,” April 2015, online at:https://rhg.com/wp-content/uploads/2015/04/RHG_UntappedPotential_April2015.pdf
20 Environmental Protection Agency, “Mitigation of Non-CO2 Greenhouse Gases in the United States: 2010 to 2030,” April 2014, online at:https://www.epa.gov/sites/production/files/2016-07/documents/mac_report_2014-us_summ.compressed.pdf.
21 Wilfried Winiwarter et al., “Technical Opportunities to Reduce Global Anthropogenic Emissions of Nitrous Oxide,” Environmental Research Letters
13 (2018) online at: http://iopscience.iop.org/article/10.1088/1748-9326/aa9ec9/pdf.
22Barron, Alexander R., Allen A. Fawcett, Marc A.C. Hafstead, James R. McFarland, and Adele C. Morris. "Policy Insights from the EMF 32 Study on U.S.
Carbon Tax Scenarios." Climate Change Economics 2018 09:01, DOI: https://doi.org/10.1142/S2010007818400031

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