Climate deal will not be renegotiated, EU tells Trump

“But we will start to negotiate, and we will see if we can make a deal that’s fair. And if we can, that’s great. And if we can’t, that’s fine,” he said.

In their first reactions, European leaders said that renegotiation of the UN treaty is not an option.

“We deem the momentum generated in Paris in December 2015 irreversible and we firmly believe that the Paris agreement cannot be renegotiated, since it is a vital instrument for our planet, societies and economies,” said a joint statement signed by German chancellor Angela Merkel, French president Emmanuel Macron, and Italian prime minister Paolo Gentiloni.

It is unclear whether UK prime minister Theresa May was also asked to sign it.

According to a press statement from the UK prime minister's residence, 10 Downing Street, Trump called May after announcing his decision.

May told Trump the UK “remained committed” to the Paris deal and “expressed her disappointment” at the US' move.

“She said that the Paris Agreement 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,” according to the UK statement.

In addition to the joint statement with Merkel and Gentiloni, Macron held a press conference in which he appealed to Americans directly in English – something unusual for a French president.

“France believes in you, the world believes in you,” he told the US.

“To all scientists, engineers, entrepreneurs, responsible citizens who were disappointed by the decision of the president of the United States, I want to say that they will find in France a second home,” said Macron.

The recently elected centrist leader changed Trump's catchphrase, and said, “Make our planet great again.”

Dutch foreign minister Bert Koenders said Trump had made "a cardinal error”, while five Nordic prime ministers said in a joint statement they would “stand by” their “promise to future generations”.

Belgian prime minister Charles Michel, who met Trump in Brussels just last week, called the pull-out a “brutal act”, while Ireland's former president, Mary Robinson, called it “unconscionable”.

It is too soon to say what Trump's decision will mean for the fight against climate change.

Finland's climate minister Kimmo Tiilikainen said the move “weakens” the impact of the Paris deal.

“It may increase the uncertainty as to the direction the international climate policy is going to take,” he said, noting that the EU must “adopt a stronger position as a climate leader, perhaps together with China”.

On Friday, the EU and China will conclude a two-day summit in Brussels with a joint declaration, which is expected to include a renewed commitment to the Paris deal.

Just before midnight, the EU had already published a joint statement with the African Union.

“The European Union and the African Union reaffirm their strong commitment to full implementation of the Paris agreement, and call on all partners to keep up the momentum created in 2015,” it said.

Such messages are not only diplomatic tools aimed at the US, but also at investors. Government action will not be enough to slow down global warming enough to avoid likely catastrophic consequences, business investments are needed too. For that to happen, they need to be reassured that there will be a market for clean technology.

Brussels-based lobby group BusinessEurope said in a comment that while Trump's decision was “a severe setback for the global efforts to protect our climate, … moving backwards on climate protection is not an alternative”.

Others noted that by shunning a low-carbon strategy, the US is forgoing potential investments and innovation.

“Those who choose to remain on the outside will miss a historic opportunity for citizens, the planet and the economy,” said Antonio Tajani, president of the European Parliament.

“The EU will continue to lead efforts against climate change and be a global pole of attraction for investment, innovation and technology, creating new jobs and boosting competitiveness,” he added.