Enlarge (credit: Getty Images | Rudy Sulgan)

This article originally appeared on Inside Climate News, a nonprofit, independent news organization that covers climate, energy, and the environment. It is republished with permission. Sign up for its newsletter here. 

Among the many obstacles to enacting federal limits on climate pollution, none has been more daunting than the Supreme Court. That is where the Obama administration’s efforts to regulate power plant emissions met their demise and where the Biden administration’s attempts will no doubt land.

A forthcoming study seeks to inform how courts consider challenges to these regulations by establishing once and for all that the lawmakers who shaped the Clean Air Act in 1970 knew scientists considered carbon dioxide an air pollutant, and that these elected officials were intent on limiting its emissions.

Enlarge (credit: Bernhardt Lang)

On Friday, the US Court of Appeals for the DC Circuit denied a request to put a hold on recently formulated rules that would limit carbon emissions made by fossil fuel power plants. The request, made as part of a case that sees 25 states squaring off against the EPA, would have put the federal government's plan on hold while the case continued. Instead, the EPA will be allowed to continue the process of putting its rules into effect, and the larger case will be heard under an accelerated schedule.

Here we go again

The EPA's efforts to regulate carbon emissions from power plants go back all the way to the second Bush administration, when a group of states successfully sued the EPA to force it to regulate greenhouse gas emissions. This led to a formal endangerment finding regarding greenhouse gases during the Obama administration, something that remained unchallenged even during Donald Trump's term in office.

Obama tried to regulate emissions through the Clean Power Plan, but his second term came to an end before this plan had cleared court hurdles, allowing the Trump administration to formulate a replacement that did far less than the Clean Power Plan. This took place against a backdrop of accelerated displacement of coal by natural gas and renewables that had already surpassed the changes envisioned under the Clean Power Plan.

Enlarge / Ozone-producing chemicals come from a variety of sources and don't respect state borders. (credit: John Edward Linden)

On Tuesday, a slim majority of the US Supreme Court issued an emergency ruling that places a stay on rules developed by the Environmental Protection Agency, meant to limit the spread of ozone-generating pollutants across state lines. Because it was handled on an emergency basis, the decision was made without any evidence gathered during lower court proceedings. As a result, the justices don't even agree on the nature of the regulations the EPA has proposed, leading to a blistering dissent from Justice Amy Coney Barrett, who was joined by the court's three liberal justices.

Bad neighbors

The rule at issue arose from the EPA's regular process of revisiting existing limits in light of changes in public health information and pollution-control technology. In this case, the focus was on ozone-producing chemicals; in 2015, the EPA chose to lower the limit on ozone from 75 to 70 parts per billion.

Once these standards are set, states are required to submit plans that fulfill two purposes. One is to limit pollution within the state itself; the second involves pollution controls that will limit the exposure in states that are downwind of the pollution sources. The EPA is required to evaluate these plans; if they are deemed insufficient, the EPA can require the states to follow a federal plan devised by the EPA.