As president of the United States, the most powerful nation on the planet, Donald Trump should be leading the global effort to avoid the worst effects of climate change.

Instead, Trump is threatening to duck the fight altogether, saying he will decide this week whether the U.S. will remain a signatory to the landmark 2016 Paris climate accord.

EDITORIAL

That’s bad news for the planet, and it goes a long way to explaining why Trump’s visit to Europe last week was judged there to be an abysmal failure. It is one thing to scold America’s allies to make good on their NATO dues. It is quite another to throw the world’s climate crisis to the wind.

Trump not only should announce the United States’ continued commitment to the accord; he should openly accept that climate change is a real threat and more generally support sound environmental policies.

Scientists warn us we are on a path to more devastating storms, higher sea levels, massive species extinctions, calamitous crop damage and social upheaval as greenhouse gases released largely by the burning of fossil fuels build up in the atmosphere. To forestall catastrophe, the 195-nation Paris accord lays out a series of voluntary goals set by each nation.

The accord includes no enforcement mechanisms, which means there is no reason for the United States to drop out. The Trump administration already has gone after such environmental initiatives as the Clean Power Plan and improved fuel efficiency for cars. If, as a result, our nation misses its stated goal on emissions, there is no penalty. To characterize the accord as a “bad deal,” as Trump has, makes no more sense.

If Trump decides to pull the United States — the world’s No. 2 emitter of carbon — out of the Paris accord, other nations might follow, shredding hopes for keeping the average rise in global temperatures below two degrees Centigrade. Other nations might also decline to contribute to a fund set up to help poorer nations reduce greenhouse gas emissions.

It’s possible rapid advances in renewable energy technology will blunt any decision to exit the climate treaty. As users turn to wind, solar or other forms of clean energy, the nation’s carbon pollution will decrease with or without the accord. States such as Illinois, which enacted a Clean Jobs bill to promote energy not derived from fossil fuels, could lead the way.

But that’s no reason to pull out of the Paris accord. It’s a reason to stay in, because meeting the goals would be that much easier.

At the G7 summit in Sicily, Italy, other world leaders tried unsuccessfully to persuade Trump to announce he is committed to the climate agreement. On Tuesday, he met with EPA administrator Scott Pruitt, who has denied the science behind climate change.

If Trump is serious about putting America first, he will announce his full support for the Paris climate accord.