Madrid, November 2 (RHC)-- Spain will host UN climate change talks in December after Chile withdrew, the United Nations said on Friday, a last-minute switch which raises big logistical challenges and has left activist Greta Thunberg stranded on the other side of the Atlantic.

The UN climate change talks, known formally as COP25, will be held December 2-13, as originally planned, but in Madrid -- over 10,000 kilometers (6,000 miles) away from Chile’s capital Santiago where it was initially meant to take place.

Chile's government on Wednesday announced here it was withdrawing as host of both the December climate summit and the Asia-Pacific Economic Cooperation summit scheduled this month, after two weeks of uprisings over inequality in the South American country left at least 18 people dead.

“Excellent news: Madrid will host the Climate Summit on December 2-13,” Spain’s acting Prime Minister Pedro Sanchez wrote on Twitter.  “Spain is working from now on to guarantee the organization of the #COP25.”

Alexander Saier, a spokesman for the United Nations Framework Convention on Climate Change, said that the Spanish government would help expedite the issuance of visas and set up an agency to help organize the travel and accommodation of the roughly 25,000 people expected to attend.

“It is more important that the conference takes place, politically.  I think it would have been not a good sign if the conference would have been canceled or postponed,” Saier said.

Madrid mayor Jose Luis Martinez-Almeida called his city’s role hosting the conference a “good opportunity to show our commitment in the fight against pollution and show that we are prepared to welcome its 25,000 attendees.”

The conference comes amid calls for swift action from environmental groups and climate protesters, with recent scientific reports urging sweeping measures to keep global temperatures from rising more than 1.5 degrees Celsius.

Teenage climate change activist Greta Thunberg, who has led a high-profile global climate strike movement to focus attention on global warming, said the change of venue for the summit had stranded her on the wrong side of the Atlantic.

Thunberg, currently in Los Angeles, traveled to the United States by yacht from Europe and had planned to continue her trip to Santiago for the climate talks carbon-free.

“It turns out I’ve traveled half around the world, the wrong way:),” she wrote on Twitter.  “Now I need to find a way to cross the Atlantic in November... If anyone could help me find transport I would be so grateful.”

Chile will continue to assume the presidency of the climate talks while in Madrid.  The so-called Conference of the Parties (COP) conference is aimed at fleshing out details of the implementation of the Paris Climate Agreement of 2015.  “We will continue to reinforce the work done with the understanding that social and environmental development go hand in hand,” Chilean Environment Minister Carolina Schmidt said on Twitter.

News that the summit will be held in Madrid comes at a tense time for Spanish politics, with pro-independence protests that have sometimes turned violent in the northeastern region of Catalonia, and the second parliamentary election this year set for November 10.

Sanchez, whose popularity has been declining, may hope the conference will burnish his international and environment credentials.

It is not the first time recently that Madrid has stepped in at the last minute as replacement host for an event that was supposed to take place in South America.  In December last year, the Spanish capital hosted the Copa Libertadores soccer final instead of Buenos Aires, after violence led the original match to be called off.