[1] The Compact highlights cities' climate impact while measuring their relative risk levels and carbon pollution.

The Compact of Mayors seeks to show the importance of city climate action, both at the local level and around the world.

Mayors Eduardo Paes of Rio de Janeiro, Brazil, Anne Hidalgo of Paris, France and Park Won-soon of Seoul, South Korea joined in the announcement, representing C40, UCLG, and ICLEI.

On 8 December 2014, World Resources Institute, C40 Cities, and ICLEI revealed the Global Protocol for Community Scale Greenhouse Gas Emission Inventories (GPC), identified as the first set of standardized global rules for cities to measure and publicly report their carbon pollution emissions.

[10] On 30 June 2015, Mike Bloomberg and Mayor Anne Hidalgo jointly announced their plans to host a Climate Summit for Local Leaders on 4 December at Paris City Hall.

[17] On 20 November 2015, the Compact of Mayors was recognized by the White House for exceeding 100 U.S. member cities prior to the COP 21 climate negotiations in Paris.

[19] Following the Climate Summit, 428 global cities had committed to the Compact of Mayors, representing over 376 million people worldwide.

[32] Foreign Minister of Taiwan Joseph Wu said “We are happy to learn that they have changed our name back to the original title".