The report’s assessments are based on a new energy-system modeling study by Resources for the Future, a centrist nonpartisan think tank in Washington, D.C.

States in the alliance will, by 2025, reduce emissions 20 to 27 percent below their all-time high, the report says. That means that only good luck—or new policy—will let the alliance achieve the Obama administration’s promise under the agreement. This partial success comes as other countries in the world gather to negotiate and announce the next, more ambitious phase of the emissions reductions.

These emissions cuts still trounce those of the states that aren’t in the alliance, which the report projects will cut emissions only 3 to 11 percent by 2025. By 2030, those states could even see their collective emissions rise by 3 percent.

Their goal to meet the Paris-plan target is pretty tough, to be honest. Trump’s administration has blocked or repealed most of the Barack Obama–era policy that sought to achieve those cuts at the national level. So the alliance is stuck working at the smaller scale of state government, and it can’t fall back on the muscle or much deeper pockets of Uncle Sam.

“When it comes to efficiency or energy standards, when it comes to fuel-efficiency standards for cars, it’s much easier to do that at federal level,” Chris Davis, a senior policy adviser for Inslee attending the UN negotiations, told me. “No one wants fragmented standards, but that’s unfortunately what you get when you oppose everything at the federal level.”

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Even if the alliance makes its goal, it will achieve less than half of the Obama-era cuts because greenhouse gases aren’t allotted proportionally across the union. The 25 governors in the alliance preside over most of the country’s population and 60 percent of its GDP—and they are happy to tell you as much. But their reach covers only about 42 percent of American carbon pollution, according to 2016 data. Texas, which emits more than 10 percent of the country’s carbon pollution, is not in the alliance.

Davis noted that it was impressive that eight states had joined since the alliance was formed and that the goals were still in reach. “To add that many states, and to do so in such a short time, and to still stay in range [of the Paris goals] is great,” he said.

Ben Grumbles, a climate adviser to Maryland Governor Larry Hogan, a Republican, told me that the alliance showed that some bipartisan efforts—such as the Regional Greenhouse Gas Initiative, a carbon-trading market among northeastern states—are popular and working. He noted that Maryland had recently committed to having a zero-emission electricity system by 2040.

“Two thousand forty is ambitious, but maybe that’s achievable,” he said. “Two thousand thirty would not be, because some of the strategies that will be a part of that—like carbon capture, utilization, and storage—will not be deployable by 2030. The key is to have a wide range of strategies to decarbonize electricity and other sectors.”