Todd Stern was the US special envoy for climate change at the State Department from January 2009 until April 2016. As President Barack Obama's chief climate negotiator, he led the US effort on the Paris climate accord. Stern is a distinguished senior fellow at World Resources Institut e and a senior fellow with the Brookings Institution . The opinions expressed in this commentary are his own.

(CNN) A year ago, on June 1, President Donald Trump staged a bells-and-whistles Rose Garden event to announce his intent to withdraw the United States from the Paris climate agreement. In doing so, he paid little attention to many of his top advisers, the vast majority of major American companies, or his counterparts around the world.

Looking back now, it is clear that this heedless act has damaged the global effort to contain climate change, and, together with two other fateful decisions, undermined US diplomacy more broadly.

In the President's fantasy, the Paris pact was an unfair deal that left partner countries laughing at us. But in fact, the agreement was so significantly shaped by the United States -- and with such attention to fixing the problems that led to US rejection of the earlier Kyoto Protocol -- that Dave Banks, a former Trump adviser in the White House, recently called it "a good Republican agreement ... everything the Bush administration wanted."

It was also a good Democratic agreement, and, more to the point, a good American and a good global agreement.

The Paris Agreement establishes -- after 20 years of trying -- the operational accord we need to deal with this increasingly dangerous global threat. It sets science-based, long-term goals, so countries have a clear destination in mind. And it is based on nationally determined action, so that all countries will participate.

Included is a regular five-year cycle to urge countries to check in, review and ramp up their efforts, so everyone can have confidence that others are acting. Countries are called on to articulate long-term objectives and strategies going out as far as 2050.

The accord moves decisively beyond the old bifurcated structure of agreements such as Kyoto, which imposed binding obligations on developed countries but asked nothing of even the most advanced developing countries, such as China.

Trump's announced intention to withdraw has already done real damage to US diplomacy on climate. I spent several days at the annual high-level climate conference in November in Bonn, Germany, and again at the "intersessional" meeting in Bonn several weeks ago. It was clear to me that countries, having worked closely with us on creating the Paris Agreement, are disappointed with the United States. In many cases countries stepped outside of their own comfort zone to accommodate us, only to see us now walk away.

Former Secretary of State Madeleine Albright famously called the United States the "indispensable nation," and in my experience she was right. When it is time to get hard things done in a multilateral context, others looked to the United States for leadership. But we are now AWOL at top levels, and that risks doing real damage as the world strives this year to complete work on crucial measures meant to implement the Paris accord.

In short, the President has hurt us diplomatically, eliminated the substantial leverage we had to secure fair treatment for the United States and our companies, and weakened an accord that plays a crucial role in combating a profound threat. He still has time to turn things around, since US withdrawal cannot become final until November 2020, but he has given no indication of any interest in doing that.

Triad of abandonment

Trump's Paris announcement needs to be seen through a broader lens as well, as part of a triad of abandonment -- including the Trans-Pacific Partnership and the Iran nuclear deal -- that the President has engineered with little regard for the impact on America's diplomatic standing.

Trump's approach runs roughshod over the fundamental, bipartisan precedent that has always guided Democratic and Republican presidents -- that they adhere to agreements their predecessors have entered into because they understand that those agreements represent the solemn promise not of Barack Obama, George W. Bush, Bill Clinton, Ronald Reagan, Richard Nixon or John F. Kennedy, but of the United States, and that this country's word matters.

The logic of this precedent should be obvious. Presidents come and go every four or eight years. If new occupants of the Oval Office felt free to cancel existing agreements and start over, US capacity to solve problems diplomatically would grind to a halt. Who could do business with us if agreements only lasted until the next election?

That Trump feels no responsibility to what has come before is perhaps unsurprising. He seems to have no historical sense of his place in the ongoing cavalcade of American presidents, who take the baton, carry it forward and know they will soon pass it on to the next in line. For him, there is only his own moment. It's all about the urge and the itch and the zing and the applause.

America extinguishes the torch under Trump

If there is a doctrine that unites this administration's approach to foreign affairs, it is not so much "America First" as "America Alone." Trump's America is uninterested in diplomatic friends and allies, and in a foreign policy where relationships are built not on personal flattery but on shared values and interests. It is an America abdicating its historic mission of democratic leadership and example, an America extinguishing the torch of liberty and welcome.

Follow CNN Opinion Join us on Twitter and Facebook

But this solo approach is not the way to get things done internationally. Getting things done depends on defining objectives, developing strategies and building coalitions based on mutual trust and confidence. None of that is in this President's repertoire.

What makes matters worse, flying solo is exactly what we don't need in an age distinguished more and more by the global nature of issues, whether climate change, trade, nuclear proliferation, pandemics, cyberwarfare or immigration. This is a moment to be developing better ways to manage urgent multilateral risks.

It is no time to go it alone.