He said that the best course of action is to create circumstances where world leaders can work together to redefine the accord, and that the world needs to take the Paris agreement as a starting point and work from there.
Trump said the deal was "very unfair" to the United States and would impact the job market.
"It is now more important than ever for cities to act and be advocates for minimizing the effects of climate change".
The vast majority of scientists believe that global warming - bringing with it sharp changes in climate patterns - is mainly the result of human activities including power generation, transport, agriculture and industry.
This is in stark contrast to Trump's desire to expand coal use in the USA, however, it is thought that the ongoing advance of renewable energy and storage systems globally means that market pressures will make this hard for the president. It removes the United States from the worldwide debate over one of the most pressing issues now facing the world, one that will result in mass migrations due to drought and hunger that will worsen global conflicts, as the Pentagon has repeatedly warned.
That brought a rebuke from Bill Peduto, the mayor of Pittsburgh, in Pennsylvania, who declared that Trump's decision did not represent his city and vowed that Pittsburgh would stick to Paris accord guidelines, regardless of the official U.S. government stance. In an exceptional step, continental Europe's three biggest economies - Germany, France and Italy - issued a joint statement in which they criticised Trump's decision and said the pact was "not renegotiable, reported Agence France-Presse".
The Paris Agreement commits governments to hold the increase in average global temperature to 2 C above pre-industrial levels.
Long a skeptic of climate change-calling it a "hoax" propagated by the Chinese to suppress USA manufacturing-this is the latest, and perhaps most significant, action taken by Trump under his "America First" doctrine, calling the agreement unfair to American workers and the economic impacts of "draconian".
Trump's rebuke of the agreement signed by 195 nations in 2015 deepened a trans-Atlantic rift laid bare during a recent NATO summit meeting in Brussels and a Group of 7 meeting in Italy, when the US president lectured other leaders on trade, climate and military spending.More news: Why China is stepping up against climate change
Li had expressed China's continued support for the global climate deal on Thursday during his meeting with German Chancellor Angela Merkel, saying, "China will stand by its responsibilities on climate change".
Supporters of the decision in USA believe pulling out of the pact will save jobs, unburden industries, and save money.
The meeting will end with a joint statement pledging full implementation of the Paris deal, committing China and the European Union to cutting back on fossil fuels, developing more green technology and helping raise $100 billion a year by 2020 to help poorer countries reduce their emissions.
Total pledges add up to $10 billion, including an unmet U.S. promise of $3 billion by U.S. President Barack Obama.
That said, Nicaragua actually refused to sign on because its diplomats believe that the Paris Agreement is too tepid in its ambitions to curb climate change, not because they are in denial that the problem exists.
He notes that even before Trump intervened, the United States was probably not going to meet its Paris commitment, and many other industrialized countries are likely to come up short. "There is no backsliding on the Paris agreement", Juncker said.
The U.S.is the world's second-largest emitter of carbon, following only China.
Tapping into the "America First" message he used on the election trail, Trump announced the withdrawal on Thursday. But "the commitments that the USA and every other country made under the Paris agreement were nationally determined, so the U.S. had control over what it said it would do, China had control over what it said it would do".