At the 2016 G-20 summit, in Hangzhou, China, world leaders united in a common determination to implement the Paris Climate Agreement before the end of the year.

The U.S., led by then-President Barack Obama, was a key player in rounding up support for the agreement. It was difficult to imagine then that the U.S. would ever turn away from this agreement, widely regarded as the world's last, best chance to rein in global warming, that it had worked so hard to forge.

Then President Donald Trump came along.

Fast forward one year later, and the U.S., now under President Donald Trump, has become such a pariah on climate change that leaders of 19 of the 20 largest economies in the world signed onto a climate and energy agenda that demotes the U.S. to a mere footprint -- literally -- on one of its pages.

In addition, America's major contribution to the climate change portion of the G-20's summary document, known as the G-20 communiqué, was to call for helping countries more easily obtain fossil fuels, such as coal and oil, whose use is causing global warming in the first place.

The G-20 communiqué issued Saturday by all the leaders struck a compromise that German Chancellor Angela Merkel had sought, by declaring that "the Paris Agreement is irreversible" while taking note of Trump's widely criticized June 1 decision to withdraw from the agreement.

The communiqué, which also addresses a host of other contentious issues including trade, reveals the rift that has opened up between the U.S. and the rest of the world when it comes to climate and energy priorities.

Take this language the U.S. inserted into the document: "The United States of America states it will endeavor to work closely with other countries to help them access and use fossil fuels more cleanly and efficiently and help deploy renewable and other clean energy sources..."

In other words, let's ship countries more oil and gas to burn, and also some renewable energy too.

Meanwhile, the climate and energy action plan discusses the need to devise plans to make deep cuts to greenhouse gases by the middle of this century, something climate scientists say is necessary in order to avert the worst consequences of global warming, but which the Trump administration is not devoting any time or resources to thinking about.

“The direction of travel toward clean energy is loud and clear. The question remains how quickly the world will surge forward and how far behind the Trump administration will let the United States fall,” said Andrew Steer, president and CEO of the World Resources Institute, in light of the communiqué and the climate and energy action plan.

Leaders of environmental groups praised the heads of the 19 nations that stood up to Trump on climate change.

“The other 19 leaders of the world’s largest economies stood shoulder to shoulder in unified support for the Paris Agreement," said Sierra Club executive director Michael Brune, in a statement.

"Given the choice between following Trump or standing strong for climate action, not a single world leader decided to back him," Brune said. "That’s unprecedented, and it shows how deeply unpopular and misguided Trump’s attack on the Paris Agreement has been, and how much damage it has done to U.S. credibility and standing in the world."