Even so, states like California and New York, which would rank as the world’s 5th- and 11th-largest economies if they were stand-alone countries, have the ability to sway large markets. For instance, their purchasing power can increase demand for things like electric buses or efficient heating pumps and potentially drive down prices.

They can also force even some global industries to embrace technological advances. America’s automakers, for instance, are now grappling with the prospect that 14 states, led by California, could soon enforce stricter pollution standards for cars than federal law will mandate, potentially splitting the American auto market in two.

A fierce battle is shaping up between California and the federal government over the authority to set pollution regulations that have a direct effect on global warming. Depending on the outcome, it could create a scenario where automakers sell different vehicles in different states or face fines if, for instance, people buy gas-guzzling S.U.V.s in one state, then cross a border to use them in a different state that has tougher emissions standards.

In the future, of course, Congress could step in and enact a federal climate policy that covers all states throughout the country. But in the meantime, few if any of the GOP-led states so far are envisioning aggressive policies to transition away from fossil fuels altogether. That growing divide among states is likely to have a powerful influence over future national policy debates.

As some states race ahead to curb their emissions and others lag behind, that could make it more complicated to design national climate policies , such as a carbon tax or national clean-electricity standard that would put a heavier burden on the most carbon-intensive states.

“It potentially makes the question of how you weave together a future federal climate policy very challenging,” said Dr. Rabe.

How heavily a state relies on fossil fuels is increasingly becoming a good predictor of how it leans in national politics. In the 2016 election, the 14 states with the least carbon-intensive economies voted for Hillary Clinton, while 26 of the 27 most carbon-intensive states voted for Donald Trump, who vowed to promote oil, gas and coal production.