After President Trump pulled the United States out of the Paris climate agreement during his first term, many Democratic-led states passed their own laws to curtail carbon emissions.

But most states that set goals for 2030 are not on track to meet them. Now, with voters worried about inflation, and with the war in Iran raising energy prices, some states have begun to cut back or abandon those goals instead.

New York’s plan, like those in other states, was to meet the target by passing a series of individual climate regulations affecting transportation, home heating, industry and utilities. The law allowed citizens to sue if regulations to meet emissions targets were not enforced.

With the state behind on its goal, it had a choice: drastically push forward on its emissions target, or abandon it.

In May, New York scrapped the state’s 2030 emissions target. Gov. Kathy Hochul, a Democrat, said sticking to the plan would have imposed “additional crushing costs” on New Yorkers.

New York is not alone in falling behind its goals. Almost every state that passed an economywide emissions target for 2030 is behind pace.

Most states need to decrease emissions 4 to 6 percent per year to hit their 2030 goals. But in the late 2010s and early 2020s — around the time when states were setting their targets — emissions in many such states were falling by only 1 to 2 percent, or in some cases rising. (The latest data we have for most states goes through 2023.)

With energy prices increasing and emissions targets seemingly out of reach, other states have begun loosening their goals as well as the policies designed to hit those targets.

This year, California’s main climate regulator effectively reduced the cost of emissions that power plants must pay as part of its “cap-and-invest” program; the regulatory board said it was responding to affordability concerns. Connecticut, Arizona and North Carolina have relaxed or removed goals for renewable energy and emissions generated while producing electricity.

The Trump administration has made it harder for states to reach these goals. It has removed consumer tax credits for electric vehicle purchases and heat pump installations, canceled federal grants for solar projects, sued states over plans to make polluters pay, halted offshore wind projects, and scaled back funding for E.V. chargers.

But there is another reason these states with ambitious goals are struggling to reach their targets: Most of them had already made a lot of progress. On the whole, they had lower per capita emissions than the U.S. average when they enacted the goals.

One major issue: States with goals already have relatively clean electricity generation. Because cleaning the power sector is one of the simplest ways for states to reduce emissions — they have authority over utilities — this puts them at a disadvantage for future reductions. (These states almost always trade electricity with other states, as well as with Canada and Mexico, but most calculations and targets take into account only the electricity generated in-state.)

“The low-hanging fruit is mostly gone in many places,” said Danny Cullenward, an economist at the University of Pennsylvania. “We need to instead be thinking about the deeper and more difficult cuts.”

There is still low-hanging fruit in a state like Kentucky, which has no climate goal. It has decreased carbon emissions more than almost any other state in the last decade, in large part because it retired coal-burning power plants while opening new natural gas plants, which are much cheaper to run and emit less carbon dioxide.

New York, on the other hand, had phased out almost all coal by the early 2010s. It already generates a significant amount of its electricity through renewables and nuclear — which means it has fewer levers to pull. Regulators have blocked the construction of new natural gas plants as part of the state’s efforts to hit its 2030 goals, but even if New York replaced all of its natural gas and oil power plants with clean energy, it would not reach its original 2030 target without additional emissions reductions in other areas such as transportation or home heating.

That’s true for almost every state that has set a carbon goal. In these states, emissions from buildings and transportation typically make up the majority of emissions, dwarfing other economic sectors.

That’s a pretty different picture from most states that don’t have goals.

And building and transportation improvements are harder to make, Mr. Cullenward said, because states have no central regulators in those sectors the way they do for the electric power sector. These are also the areas where the end of the federal tax incentives — including rebates for solar panels, heat pumps and electric vehicles — will slow state goals.

Many states passed climate goals when energy use was relatively flat, electricity was getting cleaner and emissions were dropping.

Rising demand for electricity and higher energy prices have revived debates over the cost of transitioning to green energy — including in New York.

George Borrello, a Republican state senator, said New York’s emissions goals had been an “unmitigated disaster” that helped make electricity significantly more expensive than the national average.

“We’ve set goals with no actual real plan to achieve any of those goals,” he said.

As part of New York’s climate goal, regulators were preparing to establish a cap-and-invest program that would have taken fees from polluting power plants and distributors of heating fuels, gasoline and diesel. Those costs would have been passed onto consumers as higher gas and electricity prices; the revenues would have gone back to consumers as rebates, and would have helped fund new clean plants.

Ms. Hochul directed the state to delay that plan last year, citing already-high energy prices.

In many states, the political debate revolves around how much money consumers will pay under the new programs. Ms. Hochul cited a state agency report estimating that some upstate households could pay an additional $2,500 a year under a cap-and-invest program. Many lawmakers and environmental groups dispute that estimate.

Pete Harckham, a Democratic state senator and a sponsor of the 2030 targets, said that even with the setbacks, the original goals had helped accelerate solar power in the state. This year’s state budget included $1 billion for solar projects, and solar is the cheapest per-kilowatt electricity source in New York, he said.

“What was driving high utility costs over the winter was not the state’s climate law or clean energy,” he said. “It was a price of natural gas on the spot market.”

States aren’t likely to reach emissions reductions at the scale of the Paris agreement without help from the federal government, said Joshua A. Basseches, an assistant professor of public policy and environmental studies at Case Western Reserve. But targets are still useful, he said, for guiding the state and steering utilities.

“If you come up with these incremental policies, they may not be sufficient, but they’re so much better than nothing,” Professor Basseches said. “Global communities of scientists might set targets, but the reality is the status quo is the worst.”