“The decision of the US President to withdraw from the Paris climate agreement is extremely regrettable, and I'm expressing myself in very restrained terms,” the German Chancellor said in Berlin.
“To everyone for whom the future of our planet is important, I say let's continue going down this path so we're successful for our Mother Earth.”
Ms Merkel emphasised Germany’s continued commitment to the historic accords, which she called a “cornerstone” of efforts to protect “creation”.
She said there was no turning back from the path that began with the 1997 Kyoto protocol and – until Thursday night – had the consent of almost every country in the world.
“We will combine our forces more resolutely than ever...to address and tackle big challenges for humanity such as climate change,” Ms Merkel added.
The Chancellor was applauded by politicians as she vowed that Mr Trump’s decision “can’t and won't stop all those of us who feel obliged to protect the planet”.
The White House said Mr Trump had already spoken to Ms Merkel over the phone, as well as the leaders of Britain, Canada and France, saying the US remains committed to "robust efforts to protect the environment".
World leaders have been lining up to condemn the US President’s move, following years of controversial statements on climate change including calling global warming a “hoax” and claiming it was “created by and for the Chinese” to damage American trade.
Ms Merkel had already issued a joint statement alongside her French and Italian counterparts, expressing “regret” over Mr Trump’s decision and saying the accords could not be negotiated as he claimed.
Theresa May was heavily criticised for not joining the statement, but Downing Street said she had “expressed her disappointment” personally to the President in a phone call.
“The Prime Minister stressed that the UK remained committed to the Paris Agreement, as she set out recently at the G7,” a spokesperson said.
“She said it provides the right global framework for protecting the prosperity and security of future generations, while keeping energy affordable and secure for our citizens and businesses.”
Emmanuel Macron, the new French President, said the Paris Agreement was “irreversible” and launched an appeal for global cooperation in English.
“Make our planet great again,” he tweeted, days after a frosty meeting between Mr Trump and EU leaders in Sicily.
Hours later, Mr Trump issued his own response on Twitter, writing his slogan: “MAKE AMERICA GREAT AGAIN!”
Despite global condemnation, analysts said the decision will garner favour among President’s voters, particularly those working in America’s fossil fuel industry who feel they were punished by the accords.
The President framed his decision as a “reassertion of America's sovereignty“ in a speech at the White House’s famous Rose Garden.
Mr Trump claimed the Paris deal allows countries such as China and India to carry on polluting while the US economy is harmed, complaining it is "less about the climate and more about other countries obtaining a financial advantage over the US".
He added: "We don't want other countries laughing at us anymore, and they won't."
The President claimed the US could re-enter “an entirely new transaction” but indicated that was hardly a priority, adding: ”If we can, great. If we can't, that's fine.”
Mr Trump said he was “elected to represent the citizens of Pittsburgh, not Paris”, but the city’s Democratic mayor was among vocal critics of his decision.
He joined the mayors of New York and many of America’s largest cities in pledging to uphold the Paris Agreement locally, even without federal support.
Scientists say Earth is likely to reach more dangerous levels of warming sooner as a result of the President's decision because as the world’s second-largest emitter of carbon dioxide, it contributes significantly to rising temperatures.
Calculations suggest withdrawal from the Paris Agreement could result in emissions of up to 3 billion tons of additional carbon dioxide a year - enough to melt ice sheets faster, raise seas higher and trigger more extreme weather.
Under Barack Obama, the US had agreed under to reduce polluting emissions by more than a quarter below 2005 levels by 2025, but the national targets are voluntary and leave room for manoeuvre.
In a rare statement on his successor's policies, the former President said Mr Trump had “rejected the future” but states, businesses and other nations would lead the way to protect future generations.
The White House indicated it would follow the lengthy four-year exit process outlined in the deal, meaning the issue could play a part in the next presidential election.
Additional reporting by agencies
Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies