There used to be an underwater forest of kelp along the coast of southern Maine, providing shelter on the sea floor for marine life.

But as researchers from the University of New Hampshire have documented, the kelp has largely vanished from the sea bottom south of Portland, a likely victim of man-made climate change. The Gulf of Maine is the second-fastest-warming body of water on the planet, and the absence of cold-loving kelp should sound an alarm: Just as deforestation on land threatens all the species that live in that habitat, underwater deforestation will have a profound impact on the native fish, crabs and lobsters so important to Maine’s economy.

This is not the first climate-change alarm heard from Maine, and it will not be the last. But unfortunately, the federal government isn’t listening. The Trump administration has gone from failing to show leadership on the most important environmental crisis facing the world to actively making things worse – dismantling programs that attempt to slow the emissions of heat-trapping gases that build up in the atmosphere.

The Environmental Protection Agency canceled scheduled increases in vehicle fuel-efficiency standards, and in September the federal government revoked the state of California’s waiver, which allowed it to set more demanding standards than the federal ones. California filed suit the next day to protect its standards, a lawsuit that 13 states, including Maine, have joined. Last week, California filed an expanded suit that challenges the EPA’s attempt to revoke part of a waiver it granted California in 2013, permitting the state to impose its greenhouse-gas and zero-emission vehicle standards.

Maine is also one of 23 states that have adopted California efficiency standards because air pollution from Maine cars contributes to public health problems, like our high rate of asthma and other breathing conditions. But the state also has an interest in what comes out of tailpipes 3,000 miles away in California.

When it comes to climate change, there is no such thing as a local pollution problem. The vehicles used by 40 million Californians have more impact on the temperature of the Gulf of Maine than do the ones that transport 1.3 million Mainers.

It’s bad enough that Washington has declined to provide global leadership when it’s badly needed, but the Trump administration’s attack on what little has been done already is unconscionable. Stifling action on the state level is bad policy, especially by Republicans, who have traditionally advocated giving states the freedom to act without federal interference.

“It is long established that (a state) may protect its citizens by taking innovative steps to reduce emissions and promote the use of cleaner vehicles,” Maine Attorney General Aaron Frey said in a statement. “Now, the federal government is trampling on this authority.”

Until the federal government takes the climate crisis seriously, we will have to rely on state and local efforts to slow greenhouse-gas emissions. Maine should continue to fight alongside any other state that is taking action against climate change.