WASHINGTON — President Barack Obama on Saturday hailed the newly passed international climate agreement that he said “offers the best chance we have to save the one planet we have.”

Obama, speaking from the White House, sought to trumpet what could be a legacy-defining achievement, if the Republican-controlled Congress or the courts don’t block him, or his successors in the White House reverse him.

“I believe this moment can be a turning point for the world,” Obama said. “We’ve shown that the world has both the will and the ability to take on this challenge.”

The climate agreement was reached by nearly 200 nations and is designed to curb global warming. Obama said that it will mean less of the carbon pollution that threatens the planet and more economic growth driven by investments in clean energy.

Obama said the world leaders meeting in Paris “met the moment” and that people can be more confident “the planet will be in better shape for the next generation.”

Obama said the agreement is not perfect, but sets a framework that will contain periodic reviews and assessments to ensure that countries meet their commitments to curb carbon emissions. As technology advances, targets can be updated over time. The agreement also calls for supporting the most vulnerable nations as they pursue cleaner economic growth.

“In short, this agreement will mean less of the carbon pollution that threatens our planet and more of the jobs and economic growth driven by low-carbon investments,” Obama said.

Top Republicans in Congress dismissed the pact as nothing more than a long-term planning document and said that Obama was making promises he won’t be able to keep in the months and years ahead.  They say Obama’s commitment to reduce emissions from U.S. power plants would cost thousands of American jobs and raise electricity costs.

Senate Majority Leader Mitch McConnell of Kentucky said Obama is “making promises he can’t keep, writing checks he can’t cash, and stepping over the middle class to take credit for an ‘agreement’ that is subject to being shredded in 13 months.”

And Republican Sen. James Inhofe of Oklahoma said that Americans can expect the administration to cite the agreement as an excuse for establishing emission targets for every sector of the U.S. economy.

Secretary of State John Kerry, said from Paris: “I have news for Senator Inhofe. The United States of America has already reduced its emissions more than any other country in the world.

“This has to happen,” he said of the agreement. “I believe this will continue because I just personally cannot believe that any person who doesn’t understand the science and isn’t prepared to do for the next generation what we did here today and follow through on it cannot and will not be elected president of the United States.”

Several Democratic lawmakers applauded Obama’s efforts.

House Democratic leader Nancy Pelosi hailed it as a “monumental moment” and praised Obama for his leadership on the issue.

Sen. Harry Reid, the Senate Democratic minority leader, said climate change poses one of the greatest threats the world has ever known, and that no country acting alone can stem the tide.

“The time to act is now,” the Nevada lawmaker said.