The Trump administration has been systematically dismantling the nation's climate change regulations, often claiming a high cost of compliance as justification. But a new study says keeping those rules would actually save nearly $300 billion a year by 2030.

"That just gives you a sense of the scale of the impact of the climate deregulation that's underway right now," said Jessica Wentz, a staff attorney at Columbia University's Sabin Center for Climate Change Law and one of the study's authors.

To get the figure, Wentz and a colleague took the cost-benefit analyses published by the federal government with each major greenhouse gas emissions rule issued under Barack Obama—regulations that touched on the power sector, the oil and gas industry and automobiles—and essentially added them up.

They found that the total costs associated with those rules—the costs for companies to comply, higher prices for consumers and other indirect costs—were projected to be about $84 billion per year in 2030. But in that same year, the benefits—including the direct savings from lower carbon emissions, improved public health from lower emissions of pollutants, and new jobs created by the rules—were expected to be worth nearly $370 billion. They also found that the rules would prevent the emission of the equivalent of nearly 1 billion tons of carbon dioxide in 2030.

To calculate the benefits, the government had used the so-called social cost of carbon to generate a monetary value for changes in greenhouse gas emissions. That calculation itself is now under threat from an executive order that President Donald Trump signed in March that eliminated a government-wide effort to assess such a cost.

The EPA had also found financial benefits from the climate regulations beyond cutting greenhouse gas emissions, including cost savings from greater efficiency and improved health as a result of lower emissions of smog-forming pollutants. All told, the new report says, the rules would result in 3,300 fewer premature deaths, 4,500 fewer asthma attacks, and 1,600 fewer non-fatal heart attacks per year in 2030.

Trump began an administration-wide review of existing climate and energy regulations almost as soon as he entered office. All of the rules examined by the Columbia report are either now under review or have been delayed by the Trump administration.

Here's a breakdown of the rules analyzed in the study and their projected costs and benefits in 2030 or, in the case of the oil and gas regulations, in 2025.

Clean Power Plan

Total benefits: $51.8 billion

Total costs: $5.5 billion

The Clean Power Plan would regulate emissions from the electricity sector by setting emissions reductions targets for each state. Aside from the benefits derived from lower emissions and improved health, the report says, the EPA projected that the regulations would lead to the creation of tens of thousands of new jobs (an exact figure is difficult to assess because the EPA in some cases estimated number of jobs while in other cases used an assessment called "job-years").

Auto Efficiency Standards

Total benefits: $318.2 billion

Total costs: $78.1 billion

The report looks at four sets of regulations on the fuel efficiency of cars and trucks. Some of these have already gone into effect on existing vehicles, but others are planned for coming years, and Trump has said he would have the government review them. The researchers found that the benefits from fuel savings alone would more than outweigh the cost of shifting to more efficient vehicles.

Emissions Limits on the Oil and Gas Sector

Total benefits: $1.2 billion

Total costs: $780 million

These include regulations that would cover both existing oil and gas operations on federal lands and new oil and gas equipment everywhere in the country.

Opponents of climate regulations have questioned the federal estimates that the new Columbia report used. The Heritage Foundation, a conservative think tank, has argued that the Clean Power Plan would result in higher energy costs.

For more details from the Columbia report, the authors published an extensive appendix with a full breakdown of the costs and benefits for each of the rules by category.