BEIJING — President Donald Trump’s decision to pull out of the Paris climate change agreement has thrown China, notorious for the noxious air pollution clogging many of its cities, into the unlikely position of global leadership on climate change — whether it wants the job or not.

Environmentalists in the country condemned Trump’s decision on Friday even as they expressed doubts about how ready China is to pick up the slack.

“I feel that China is not eager to take on the leadership role,” said Ming Sung, the former chief Asia Pacific representative of the Clean Air Task Force and a senior adviser to a number of environmental groups. “They’re still trying to nudge the Western world — the EU and the US — to continue to take on a bigger role.”

It’s a surprising spot for China, the world’s largest emitter of greenhouse gases, which less than a decade ago was better known for its growing contributions to global carbon emissions than for its role in mitigating them.

In 2009, Beijing faced heavy international criticism for blocking more ambitious commitments at climate change talks in Copenhagen, and for refusing international verification measures. But the confluence of a slowing economy and heavy public pressure to tackle air pollution have ensured the Chinese leadership is, by all accounts, set to follow through on its commitments to mitigating carbon emissions — even if the US is not.

Trump’s decision comes after months of speculation among Chinese environmental and policy groups that the US would pull out of the Paris deal. As Trump made his statement, Chinese Premier Li Keqiang was at a summit with EU leaders in Brussels, where the two sides vowed to speed up the transition to clean energy.

Before Trump announced his decision, Li called combating climate change an “international responsibility” that was a point of consensus around the globe.

In contrast, Trump said the Paris deal put “draconian financial and economic burdens” on the US, emphasizing it was unfair to Americans. Trump has previously called climate change a hoax perpetrated on the US by China to undermine American industry.