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EnvironmentSupporting Sustainable CitiesAmerican Cities Climate Challenge

American Cities Climate Challenge

As hubs of talent and innovation, American cities are uniquely positioned to take bold action to fight climate change and improve the health, economy, and well-being of their residents. Especially after former President Trump’s decision to withdraw the U.S. from the Paris Agreement, American cities became even more emboldened to take on the challenge of climate change head-on. Launched in 2018, the American Cities Climate Challenge provides powerful resources and support to 25 U.S. mayors as they accelerate climate action, using a holistic approach that focuses on clean buildings and transportation. 

Climate Challenge actions will reduce CO2 emissions by 74 million metric tons from 2020 through 2030 – compared to a business-as-usual scenario.

Participating cities are scaling and implementing climate solutions to help grow the economy, protect public health, and upgrade city infrastructure to meet the needs of the 21st century. Each winning city received a unique package of support, including additional staff capacity, technical assistance from world class partners, access to intensive peer-to-peer networking and support in launching communications, outreach and education campaigns. In total, actions from the Climate Challenge will reduce CO2 emissions by 74 million metric tons from 2020 through 2030, compared to a business-as-usual scenario. Notably, when evaluating the combined work of all cities, including action taken outside of the Climate Challenge, cities are collectively on track to reduce emissions by 32 percent below 2005 levels by 2025, which will beat the 2025 Paris Agreement goal of a 26 to 28 percent reduction.

Examples of policy and programmatic initiatives that were facilitated with support from the Climate Challenge include:

  • St. Louis’ Building Energy Performance Standard (BEPS) ordinance requires at least 65 percent of the buildings of a certain property type to improve their energy efficiency, thereby reducing greenhouse gas emissions and boosting job creation and economic development.
  • Portland’s citywide network of street improvements have helped to speed transit service and increase transit ridership.
  • Cincinnati’s WarmUp Cincy program assists tenants who live at or below the poverty line with in-unit energy equipment upgrades and financial help to pay energy bills.
  • Nearly half of the cities procured renewable energy using tried-and-true purchasing and financing methods, helping to set a nationwide record for local government renewable energy procurement in 2020.


Advancing Climate Policy through our American Cities Climate Challenge

American Cities Climate Challenge by-the-numbers as of June 2021:


  • 23 policies passed
  • 30 programs launched
  • 400 million square feet covered by new benchmarking policies
  • 37,000 energy audits completed


  • 31 policies passed
  • 41 programs launched
  • 1,136 new electric vehicles in city fleets
  • 510 miles of new improved bike lanes
  • 37 lane miles of bus/transit improved

Now, as the U.S. federal government springs into action on climate under President Biden, these cities will continue to innovate, test what works, and maintain momentum as federal climate policy expands and evolves.

The Bloomberg American Cities Climate Challenge winning cities are:

  • Albuquerque, NM
  • Atlanta, GA
  • Austin, TX
  • Boston, MA
  • Charlotte, NC
  • Chicago, IL
  • Cincinnati, OH
  • Columbus, OH
  • Denver, CO
  • Honolulu, HI
  • Indianapolis, IN
  • Los Angeles, CA
  • Minneapolis, MN
  • Orlando, FL
  • Philadelphia, PA
  • Pittsburgh, PA
  • Portland, OR
  • Saint Paul, MN
  • San Antonio, TX
  • San Diego, CA
  • San Jose, CA
  • Seattle, WA
  • St. Louis, MO
  • St. Petersburg, FL
  • Washington, DC

Top photo: Mike Bloomberg announces St. Petersburg, FL as a winner in the Bloomberg American Cities Climate Challenge alongside Mayor Rick Kriseman.