The Trump administration's pullbacks on the Iran nuclear and Paris climate deals will make it harder for other countries to take the U.S. seriously on a range of topics, former Energy Secretary Ernest Moniz said Wednesday in Washington.

Trump's announcements have "challenged the cohesion of the U.S. and its allies," he said. "If we aren't going to follow agreements ... from Paris to Iran … it's kind of like, what's the point," Moniz said, speaking at the Bipartisan Policy Center think tank. European allies are not "walking with us," he added.

Moniz, a nuclear physicist, was a key architect of the Iran nuclear weapons deal under former President Barack Obama. He was also a top proponent and negotiator for joining the Paris climate change deal in 2015.

Trump threatened last week to "cancel" the Iran nuclear deal unless Congress and European allies can develop a plan to curb the regime's nuclear program and regional aggression. Trump announced the decision to withdraw from the Paris climate deal on June 1.

But Trump's antagonism on both international agreements may come to harm the U.S. when the president needs to work with its partners in Europe and around the world, Moniz said. The biggest of those issues is nonproliferation, especially in the Middle East where Saudi Arabia, Egypt, and the United Arab Emirates are pursuing civilian nuclear programs while making informal commitments to buy reactors from Russia, he said.

Moniz, who has been involved in the nonproliferation debate for the last three decades, said the U.S. is slowly losing its ability to maintain its nuclear expertise on power generation and on weapons development. That will hurt the nation in the future, but it also makes the U.S. less credible when it comes to its influence on nuclear development in the Mideast.

"If we don't maintain the capacity, we lose the ability to do that," Moniz said. The U.S.'s influence on nuclear nonproliferation is grounded in the "strength of our nuclear supply chain."

He said most of the nuclear weapons being developed today are using fissile material harvested a decade ago. Moniz issued a new report from his think tank, the Energy Futures Initiative, that recommends a series of actions required to beef up the nation's nuclear supply chain, including a skilled nuclear labor force, which is fading.

Moniz suggested the Iran complication is just the tip of the iceberg about nuclear materials development in the Middle East. He suggested that Russia currently could hold more influence than the U.S.

On climate change, Trump's withdrawal from the Paris Agreement will be a "little bit of a delay, shall we say," but the market has already changed in favor of low-carbon energy. "We aren't going back," he said, despite Trump's decision. "We are heading to a low-carbon future."