(CNN) Pulling out of the Paris Agreement on climate change would do "enormous damage to the standing of the United States in the world," says the man who negotiated the deal on behalf of the country.

President Donald Trump is expected to make a decision soon on whether to exit the Paris Agreement. On the campaign trail, candidate Trump promised to "cancel" the accord. It's the world's first comprehensive climate agreement -- adopted by nearly 200 nations.

Todd Stern, former US special envoy for climate change under President Barack Obama, also says it could affect the United States' ability to seek international cooperation on a whole host of other issues, not just climate matters.

"It's a kind of 'To hell with you' with respect to an issue that countries have been enormously concerned about," Stern told CNN's "The Lead" with Jake Tapper on Friday. "You will see US credibility and leverage in the international community absolutely reduced, because this is an issue that people care about, and that they know they can't solve without US engagement."

Also under consideration by the Trump administration: whether to remain in the agreement, and simply reduce the United States' commitment to reduce its carbon emissions 26%-28% from 2005 levels by 2025. Stern says that option is a "bad signal, bad example to others -- but it's better than pulling out of the agreement all together."

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