Two years ago, President Donald Trump signed an executive order for a review of actions that could stop the tapping of fossil fuel reserves for energy resources. It also revoked Obama administration efforts to prepare and protect the country from the impacts of climate change.

The Obama-era rule, the Clean Power Plan, encouraged generating electricity using renewable energy and closing heavily polluting plants; it was a welcome direction. But the U.S. Environmental Protection Agency’s proposed replacement, known as the Affordable Clean Energy (ACE) rule, slashes restrictions on coal-burning plants.

Hawaii is among a group of 29 states and cities that this week filed a lawsuit that aims to block the new rule, rightly asserting that through it the EPA ignores its responsibility under the Clean Air Act to set limits on greenhouse gases. Coal is most in need of restriction because it generates more greenhouse gases than any other electricity source.

The ACE rule discards the first national limits on carbon dioxide pollution from power plants. Instead it tasks states with deciding whether to scale back emissions by way of technologies that improve power plant efficiency. Such easing could result in toothless clean-energy initiatives.

In Hawaii’s case, the state has a mandated ambitious 2045 deadline for generating 100% of electricity sales from renewable resources, and should press on to meet state-imposed milestones, such as producing a renewable portfolio standard (RPS) in which 30% of electricity sales are in renewables by 2020.

In recent years, coal has served as the source for 15-20% of Hawaii’s electricity production — the runner-up to imported oil.

Now, Hawaiian Electric Companies has launched an effort to find new, clean-energy projects to provide replacement service as coal-fired AES Hawaii on Oahu is slated to be retired in 2022. This move is encouraging, though coal use may not be entirely scrapped here.

This year, state lawmakers shelved a proposal to prevent the state Public Utilities Commission from allowing coal-burning power after the plant’s closure. Both Hawaiian Electric and AES opposed the bill, maintaining that coal — the cheapest among grid energy sources — could be a go-to contingency should clean-energy alternatives fall short.

Environmental groups countered, persuasively, that Hawaii should opt to be “coal-free by 2023” due to climate change threats, such as sea level rise, and concern about coal’s mercury content. The neurotoxin can make its way into the soil and water. Moving toward clean energy targets, the state must avoid setting the stage for coal resurgence.

Last year, the Hawaii Climate Commission adopted the “Hawaii Sea Level Rise Vulnerability Adaption Report,” which projects sea level rise of 3.2 feet over the next 30 to 70 years, with potential impacts on Oahu alone including the loss of $12.9 billion in structures and land.

One dozen jurisdictions, including several California cities facing similar threats, are suing dirty-energy companies that they assert knowingly contributed to climate-related problems by disseminating misleading information for the sake of protecting business pursuits.

Rhode Island, the sole state in this group to date, is suing BP, Chevron, ExxonMobil and Shell in state court, seeking to hold them financially accountable for playing a role in climate-related damages.

At the national level, meanwhile, the EPA maintains that loosening regulation via the Affordable Clean Energy rule will give states more flexibility in addressing environmental issues. That’s quite a spin for a proposed weakening of coal restrictions. Whatever happens on the federal level, though, Hawaii must hold to the state’s goals and stay the course for science- backed protections.