Syria has officially signed up to the Paris Agreement, the UN said Tuesday, leaving the United States as the only country to reject the global climate-rescue pact.
"The Syrian Arab Republic deposited its instrument of accession of the Paris Agreement on 13 November 2017," said the UN climate secretariat (UNFCCC) hosting the annual round of global climate negotiations in Bonn, Germany.
War-torn Syria became the 169th of 196 countries that are members of the UN climate convention to take the legal step of ratification.
After Nicaragua signed up in October, Syria was the only country not to have adopted the pact. Another 27 nations that have signed the treaty have yet to pass domestic laws required for full accession.
The United States, which championed the agreement under Barack Obama, adopted it in the French capital in December 2015, signed it at the UN in April 2016, and ratified in September last year.
But in June this year, Obama's successor, Donald Trump, announced that America would pull out of the agreement, which he said imposed "draconian financial and economic burdens" on the United States.
The US can only withdraw four years after the deal officially entered into force in November 2016, which means November 2020 — two months before Trump's term ends.
The hard-fought pact commits countries to limiting average global warming to under two degrees Celsius (3.6 degrees Fahrenheit) over Industrial Revolution levels, and 1.5 C if possible, to avert calamitous climate change-induced storms, drought and sea-level rise.
To bolster the agreement, nations submitted voluntary commitments to curb greenhouse gas emissions from burning coal, oil and natural gas.
But the 1 C mark has already been passed, and scientists say that on current country pledges, the world is headed for a 3 C warmer future, or more.
Many fear that America's exit from the agreement will make the 2 C goal that much harder to reach.
On Monday, a White House delegation hosted a controversial event on the sidelines of the UN climate conference, promoting "cleaner" fossil fuel use to the chagrin of green energy campaigners and fellow negotiators.