Nicaraguan President Daniel Ortega has announced that his country will sign the Paris Agreement, leaving only two countries out of the global effort to tackle climate change - the United States and Syria.

"When the only country left in the world that hasn't signed the Paris Agreement is Syria, President Trump's decision to withdraw from the accord stands out like a sore thumb," said David Waskow, international climate director at the World Resources Institute (WRI). "The Trump Administration's reputation as a climate loner deepens even farther."

Unlike the US, Nicaragua had refused to sign the agreement on grounds that it didn't go far enough to tackle climate change. The small Central American country wanted to see bigger emissions cuts from the wealthy, industrialized nations responsible for the bulk of the carbon in our atmosphere.

But earlier this week, Ortega told Nicaraguan state media that his country would soon sign the Paris Agreement, in solidarity with vulnerable countries in Africa, Asia, Latin America and the Caribbean that had already done so.

"We have to be in solidarity with this large number of countries that are the first victims, who are already the victims, and are the ones who will continue to suffer the impact of these disasters," Ortega said, according to Nicaraguan media.

Could the US renegotiate terms?

During his election campaign, Trump pledged to pull the US out of the international agreement. He formally announced that the country would withdraw in June, citing the "draconian financial and economic burdens the agreement imposes on our country."

During a climate change meeting between environment ministers in Montreal earlier this week, US officials reportedly said the US would consider rejoining the agreement, but the Trump administration denied any shift in stance. 

"There has been no change in the United States' position on the Paris agreement," the White House said in a statement. "As the President has made abundantly clear, the United States is withdrawing unless we can re-enter on terms that are more favorable to our country."

Andrew Light, senior fellow at the WRI Global Climate Program, told DW there was some confusion over the US position over the weekend, but the Trump administration had been fairly consistent since July that it would be willing to "re-engage" in the Paris Agreement - meaning to revise its pledge.

The US lowering its commitment to cut carbon emissions might not be popular with other signatories, but Light says legal assessments suggest it would be permitted under the terms of the agreement.

"I don't think that any country would welcome any other party revising downward their target, but given that the targets themselves are not legally binding I don't believe there would be any legal recourse that they could make in response to that," Light told DW.

Trump against the world

Speaking at the Montreal event on the sidelines of the general assembly, UN Secretary-General Antonio Guterres warned that the Paris Agreement's current pledges would not be enough to reach its goal of keeping the global temperature rise well below 2 degrees.

By 2020, he said, "we need to make sure that we have substantially raised the bar of ambition."

World leaders including the UK's Theresa May, Chile's Michelle Bachelet, and South Africa's Jacob Zuma, underlined the importance of climate action and the Paris Agreement in speeches at the UN General Assembly this week.

Light says the US position is of concern to some countries, not only for its impact on emissions but also because of implications for climate security and development aid.

"We're doing so much climate-related development assistance around the world, if the administration were to apply some sort of climate litmus test to that assistance... countries are worried," Light said.

"I think this will impact their relationship with the United States because they do see climate change as a threat, regardless of what the US administration thinks, and they are relying on that assistance."

He added that Nicaragua may have decided to sign up to the agreement to avoid being placed in the same camp as Trump.

"I expect that they were weary of being called out as a hold-out on this along side the Trump administration and they didn't want to stand on that side of the line on the issue," Light said.