At the COP31 climate summit in Antalya, Turkey, John Kerry called Donald Trump “the biggest loser we’ve seen in a long time,” arguing that his retreat from climate action is weakening the United States’ position in the clean-energy race with China.

The U.S. government sent no official delegation to the United Nations-backed summit, attended by nearly 200 countries; U.S. participation instead included Gavin Newsom, Sheldon Whitehouse, Tim Walz, Michelle Lujan Grisham, mayors and members of Congress.

The White House dismissed the summit as supportive of “extremist climate policies,” as the Trump administration withdrew the United States from the international climate process, reversed much of Joe Biden’s clean-energy support, rolled back tax breaks, imposed tariffs and directed public funds toward coal plants.

Newsom said the federal retreat threatens U.S. competitiveness and automobile manufacturing, and called the absence of federal representatives at COP a disgrace.

Kerry warned that the U.S. approach weakens American businesses and gives China an edge in clean technology, saying the country had “walked away from the battlefield” rather than compete.

In response, coalitions representing 24 governors and 350 mayors across 47 states pledged to work with the United Nations to track U.S. greenhouse-gas emissions and report progress toward decarbonization; their constituents account for 55% of the U.S. population.

State and local groups will contribute to the global stocktake of progress toward climate goals, due to conclude in 2028, even as the United States is set to leave the UN climate treaty framework in February 2027.

A report from America Is All In and the University of Maryland Center for Global Sustainability estimates that state-level policies, market forces and falling technology costs could reduce U.S. carbon dioxide emissions by as much as 46% below 2005 levels by 2035.

Rapid growth in renewable energy helped avert some new fossil-fuel power generation, and global emissions edged down slightly last year, but summit participants said much deeper cuts are needed to avoid catastrophic climate change.

UN secretary general António Guterres urged countries to phase out fossil fuels, while Greta Thunberg called climate summits “greenwashed circuses” because of their slow progress.

Kerry said frustration over high energy bills and climate concerns contributed to Democratic gains in the recent U.S. midterm elections, and he expects the issue to return to Washington’s agenda.

Newsom and Walz said the election results gave them renewed optimism, though Newsom cautioned that Democratic influence could only partly limit environmental-policy damage during Trump’s remaining two years in office.