Groups working to curb climate change said a Supreme Court ruling limiting the ability of the Environmental Protection Agency (EPA) to control carbon emissions is a major setback in their fight.

The justices, on a 6-3 vote along ideological lines, ruled only Congress can set limits on carbon monoxide and other pollutants, in Arizona and elsewhere. Going forward, the EPA must have clear congressional authorization to formulate most regulations.

Kirti Datla, director of strategic legal advocacy for Earthjustice, said the ruling could affect other regulatory agencies as well.

"If a court thinks that what an agency is trying to do is too new or too big, or addressing too important of a problem, it's going to basically assume that Congress didn't give the agency that authority," Datla explained.

Climate-change activists vow to fight the ruling, but a deadlocked Congress will make it difficult. In recent years, Phoenix and other Arizona cities have passed resolutions calling for emissions cutbacks, but state regulators have not made them mandatory for energy producers.

Datla pointed out in its ruling, the high court invoked a rarely-used rule known as the "major questions doctrine," which blocks the EPA and potentially other agencies from setting regulations deemed "transformational" to the economy unless Congress approves them first.

"There's some reason for concern that all the environmental laws, and kind of the system that's existed for the last 50 years that we've taken for granted keeping us safe -- or at least, safer than we would have been -- are being challenged," Datla emphasized.

Datla noted the ruling negates an Obama-era doctrine which set carbon limits aimed at pushing states to use less coal and more alternative energy sources. She thinks the decision could also undo a recent executive order requiring all federal agencies to take steps to reduce their carbon footprints.

"I think the bottom line here is that the decision is bad, and that it takes a highly effective way of regulating emissions from power plants off the table," Datla asserted. "Those emissions are an incredibly important piece of solving the climate puzzle."

According to the U.S. Energy Information Agency, coal and other hydrocarbon-based fuels account for almost 80% of U.S. power generation, while renewables make up 12%. The Biden Administration's goal is to cut greenhouse gases in half by 2030, and make the nation carbon-neutral by 2050.

Conservation groups along several states on the East coast stretching from North Carolina to northeast Florida are working through a plan to conserve one million acres of salt marsh nearly the size of Grand Canyon National Park.

When it comes to Mother Nature, state boundaries are non-existent - so environmental groups, scientists, native communities and state and federal agencies are working together on the South Atlantic Salt Marsh Initiative Project.

It's a voluntary, collaborative plan to help states protect channels of coastal grasslands that do more than meets the eye.

Kent Smith - a biological administrator with the Aquatic Habitat Conservation and Restoration Section of the Florida Fish and Wildlife Conservation Commission - said salt marshes are extremely good at sequestering carbon from the atmosphere by forming a thick peat to trap the CO2 in the sediments below.

"They also stabilize the shorelines in coast areas," said Smith. "So they keep sediments in place and they protect properties from the impacts of climate change, sea-level rise, tropical storms, things like that."

Smith said coastal development threatens the natural protections salt marshes provide, and their hope is to spread awareness so communities and developers can work together to protect these natural habitats.

Jim McCarthy - president of the North Florida Land Trust - is part of the initiative and works to buy salt marshes to preserve and protect them. He said manmade solutions to protect areas from things like storm surges don't always work.

He said one example is in Jacksonville, where marsh grasses were taken out of an area and replaced with concrete bulkheads. He said that was disastrous during Hurricane Irma.

"And as the St. Johns River turns east," said McCarthy, "it literally went over its banks because there is nothing to make the energy out of it and there is nothing to absorb it, if you will, as there would be if you had had natural marsh grasses. "

The National Oceanic and Atmospheric Administration estimates that the U.S. loses 80,000 acres of coastal wetlands, including salt marshes, each year, driven by development and sea-level rise.

Support for this reporting was provided by The Pew Charitable Trusts.

West Virginia has received federal Infrastructure Bill funding to complete the Corridor H Highway, a four-lane route beginning in Tucker County and connecting with Interstate 81 in Strasburg, Virginia.

Some environmental groups and local residents argued the project's current route could disrupt wildlife habitat and local economies based on outdoor recreation and tourism.

Hugh Rogers, board member and chair of the highways committee for the West Virginia Highlands Conservancy, said small towns around Blackwater Falls would feel the impact from increased traffic and congestion.

"The people on the mountain who live in Thomas and Davis, they don't want a four-lane slamming right between their towns," Rogers emphasized. "And causing a whole different kind of development probably from the kind that has been very successful."

More than 120 miles of Corridor H is now open, with around 30 miles left to complete, according to the West Virginia Department of Transportation. The state maintains the project will open up remote areas in Grant, Tucker and Hardy counties to economic development and shorten travel times through the mountains.

But Rogers countered the outdoor tourism small businesses and residents have worked to build up around Blackwater Falls is at stake. He pointed out travelers come to the area to escape major development.

"And there's just all this opportunity for recreation," Rogers explained. "As you know, mountain biking is very big around here. Lots of hiking, of course. Rafting and kayaking on the river, it's just a wonderful playground"

He added nearly 2,000 residents have signed an online petition calling for the highway's path to be diverted from the Blackwater region to an alternate route.

"For years, people thought, we have to take whatever the Department of Highways gives us; we just 'want' the changes that it will bring," Rogers noted. "Now, more and more people are getting the idea that we don't have to settle for a lousy version of this."

Research from the Allegheny Blue Ridge Alliance shows the highway could potentially impact threatened and endangered species such as Cheat Mountain salamander, Indiana bat, Virginia big-eared bat and West Virginia flying squirrel.

Idaho has issued its first major permit for a gold mine east of McCall. Conservation groups and the Nez Perce tribes say the project raises alarm bells.

The Idaho Department of Environmental Quality issued an air-quality permit to Perpetua Resources Idaho for its Stibnite Gold Project, an open-pit mine proposed at the headwaters of the East Fork of the South Fork Salmon River.

Josh Johnson, senior conservation associate for the Idaho Conservation League, said there are concerns about particulate matter from the mining, especially the carcinogen arsenic, which the area's rocks naturally contain in high levels.

"The arsenic gets attached to what's called the fugitive dust," Johnson explained. "The dust that is just getting thrown into the air by different operations or by vehicle traffic, and that arsenic is one that can obviously have big impacts on human health if it's in high enough concentrations."

The Idaho Conservation League, Save the South Fork Salmon and Nez Perce Tribe have appealed the Idaho Department of Environmental Quality's decision, arguing officials violated the federal Clean Air Act and state regulations. Perpetua Resources countered it will be mining for antimony, which is used for storage batteries, and noted the mine will create jobs.

Fred Coriell, a board member for Save the South Fork Salmon, said the conditions in the air quality permit are essentially voluntary and not legally enforceable.

Coriell emphasized without stringent controls, his organization is concerned the project could have health consequences for people who use the area.

"There's a lot of recreation that our members do up there: hunting, fishing, floatboating, berry picking, hiking, family camping," Coriell outlined. "They pass through the mine site to access areas that are in and around Frank Church Wilderness."

The Nez Perce Tribe said the mine would be within its "aboriginal homeland where the Tribe has treaty-reserved rights and natural resources, cultural resources and sacred sites."

Other permits and regulations are required for the project to move forward, including an environmental review by the U.S. Forest Service.