They also agreed to meet goals similar to those in the Paris climate accord, which President Trump announced earlier this year the USA would withdraw from.
The American economy's success comes down to environmental policies put in place during the Obama administration, said former President Barack Obama during a speech Tuesday as he jokingly thanked himself.
They will build on UNESCO's updated Strategy for Action on Climate Change, adopted by the 195 Member States in November at the General Conference.
Despite Trump's unwillingness to participate until the agreement is renegotiated, individual American companies - along with USA states and cities - have stepped up their commitment to the deal. "It was going to be up to all of us".
Chicago officials billed the North American Climate Summit, which began Monday evening, as the first of its kind for the city.
"But the good news is that the Paris agreement was never going to solve the climate crisis on its own", Obama stated.
The need for greater cooperation among cities is evident by the environmental challenges they face, Steve Adler (D), mayor of Austin, Texas, said during the charter's signing ceremony.
The agreement requires the cities to track and publicly report city emissions, advocate for greater local authority and flexibility to take aggressive action on climate, and incorporate the realities of climate change and its impacts into local infrastructure and energy planning.
On Tuesday, they will sign the Chicago Climate Charter, which aligns with the Paris climate accord, an agreement President Donald Trump's Administration pulled the USA out of earlier this year. "We just hope the president of the United States wakes up" and recognizes the importance of addressing climate change.
The Trump administration has made multiple decisions to end or reverse Obama-era policies focused on combatting climate change. Trump has said the terms of the agreement should be more favourable to businesses and taxpayers.
In lieu of the nation's withdrawal from an worldwide agreement on climate change, 50 municipal leaders from around the country, including Portland Mayor Ted Wheeler, signed a charter Tuesday committing their cities to emissions reductions.
"There is an absence of leadership out of Washington", said Chicago Mayor Rahm Emanuel, who served as Obama's White House chief of staff. "But we're all in on the Paris protocols".