Climate change is not a theory, and it’s not something that is happening far away from Maine.

Heat-trapping gases in the atmosphere are already warming the air and water, changing their chemical composition and contributing to severe weather.

In Maine, we can expect damage from coastal flooding, the decline of fisheries (including the lobster industry), longer allergy seasons, the end of our mild summers and more instances of chronic breathing ailments like asthma.

That’s why Mainers should applaud the announcement Monday of proposed rules by the Environmental Protection Agency. In what would be the most ambitious step to date to address the world’s most serious environmental problem, the rules would regulate carbon pollution from power plants for the first time, reducing their emissions by 30 percent by 2030.

The proposed Clean Power Plan is based on the same concepts as the Regional Greenhouse Gas Initiative, which has lowered carbon emissions dramatically, while investing millions in energy efficiency and lowering power prices in New England and the mid-Atlantic states.

The architect of RGGI was then-Massachusetts environmental regulator Gina McCarthy, who is now the administrator of the EPA. She made clear in her remarks Monday that her target is not an esoteric environmental issue with distant effects.

“This is not about disappearing polar bears or melting ice caps,” McCarthy said Monday. “It’s about protecting our health and our homes. This is about protecting local economies and jobs.”

What McCarthy has proposed is setting carbon emission reduction targets for each of the 50 states, giving each of the states the flexibility to comply with them. A model for many states may be RGGI, and there is no reason that Maine and its partners should not stay on the course they have taken since 2008.

Under RGGI, power generators and industrial facilities buy allowances at auction to release greenhouse gases. The proceeds from those auctions are used to invest in energy efficiency, which reduces overall emissions. Over time, the total allowed amount of emissions shrinks, leaving it up to the market to determine the most cost-effective way to meet the goal.

The program has been a success. In 2013, RGGI states more than met their target for cutting greenhouse emissions, while electricity prices have dropped. As an added benefit, the level of other pollutants has shrunk even faster as a byproduct of the RGGI process.

While Maine should be able to continue on its path, it could benefit from other states changing theirs. Manufacturing in polluting states with aging plants and access to low-cost coal has enjoyed an advantage over competitors in Maine. And Maine has hydro, wind and biomass power that would be in demand if other states were forced to move to cleaner electricity.

Increased demand for renewable power could be expected to lower prices, driving a transition that would slow down global climate change.

The proposed rules will be targeted by the coal industry and large polluters. It’s important that members of Maine’s congressional delegation – Democratic, Republican and independent – stand up for this common-sense rule change that would benefit Maine people.

Maine’s traditional industries, agriculture, forestry and fishing, as well as tourism and hospitality, would all be hurt by unchecked carbon pollution. We can’t afford to pay the high cost of doing nothing.