President Trump's statement is a very clear repudiation of the Paris climate agreement and international efforts to fund climate mitigation and adaptation in poorer countries.
In many ways it is far worse than many observers had expected.
The president clearly believes that the accord is a job killer, an economy strangler and a desperately unfair stitch-up by other countries wanting to take economic advantage of the US.
"We don't want other leaders and other countries laughing at us anymore," thundered President Trump, "and they won't be."
He spoke of being open to re-negotiating the deal or trying to build a new agreement - but the idea of re-working the accord is an unlikely scenario.
French President Emmanuel Macron has already dismissed the idea.
"The President said that they could continue to talk, but indicated that nothing was renegotiable with regard to the Paris accords. The United States and France will continue to work together, but not on the subject of climate change," sources close to the President were reported as saying.
"President Trump's speech was confused nonsense," said Bob Ward from the UK's Grantham Research Institute on Climate Change.
"He announced that the United States will withdraw from the Paris Agreement on climate change, while also launching negotiations to re-enter the agreement.
"But the agreement states that no country can withdraw within three years of it coming into force, and the process of withdrawal takes a further year to complete.
Mr Ward continued: "That means the United States cannot complete withdrawal from the Paris Agreement before 5 November 2020, the day after the next presidential election in the United States. So Mr Trump will not have withdrawn from the agreement within this presidential term."
The scale of President Trump's opposition to the deal is all about the money. He sees the accord as "a massive redistribution of US wealth to other countries". This is a clear indication that he has fully bought into an economic nationalist and climate sceptic perspective supported by several members of his inner circle.
Others don't see climate change that way.
"Today's decision is not only disappointing, but also highly concerning for those of us that live on the front line of climate change," said Marshall Islands President Hilda Heine.
"While today's decision will have grave impacts, it is not too late to act. We must not give up hope. Our children and their children deserve not only to survive, they deserve to thrive."
She added: "That is why the rest of the world remains firmly committed to the Paris Agreement, and our own commitment to it - and that of our wider Pacific family - will never waver."
Again and again, the question of unfairness cropped up in President Trump's lengthy statement. The "world's worst polluters", which he argued were China and India, had "no meaningful obligations" placed on them by the Paris deal.
Pulling the US out of the deal was, he said, his way of choosing Pittsburgh over Paris. However, the mayor of Pittsburgh rejected the association. Bill Peduto tweeted: "I can assure you that we will follow the guideline of the Paris agreement for our people, our country & future."
The president was scathing about the green climate fund, saying it would cost billions of dollars - the US has pledged $3bn and paid around $1bn.
The overall tone and content of his speech clearly plays to the support base that elected him but is also a clear disavowal of multilateralism, especially on climate change, and will definitely push other countries more closely together on this issue.
In an interview with the BBC, former US Secretary of State John Kerry, who signed the Paris accord on behalf of the Obama administration in 2016, said of Trump's "laughter" comments: "I think other countries will stop laughing at us when we don't have announcements like we had today and we have a presidency that offers America a greater vision of the possibilities of the future."