Greta Thunberg alights from a train to march on COP 25 Madrid

Youthwave to crash on climate change conference amid dire warnings

Swedish environmental activist Greta Thunberg delivers a speech as she attends the 'March for Climate', demanding action against climate change during the COP25 Climate Summit in Madrid. EPA

Spanish actor Javier Bardem speaks onstage during a mass climate march to demand urgent action on the climate crisis from world leaders attending the COP25 summit, in Madrid. AFP

Climate change activist Greta Thunberg holds a press conference with other activists in Madrid. Getty Images

Ninari Chimba of Ecuador denounces the effects of climate change on Indigenous Americans during the 'Fridays For Future' climate change mass protest in Madrid, Spain. Getty Images

A person wears a Donald Trump mask during the 'March for Climate', a protest demanding action against climate change during the COP25 Climate Summit in Madrid, Spain. EPA

Climate activist Greta Thunberg speaks to assistants during a demonstration in Madrid. AP Photo

An ingenious woman burns incenses during a climate change protest march, as COP25 climate summit is held in Madrid, Spain. Reuters

Teenage activist Greta Thunberg pulled in on the overnight train to Madrid on Friday, heading to a gathering of world leaders she says are failing to combat climate change.

In just over a year, Ms Thunberg has inspired younger protesters in a global movement demanding action to slow the atmospheric warming that climate scientists say could ultimately endanger the survival of industrial societies.

Stepping off the night train Lusitania at Chamartin train station in the Spanish capital, the 16-year-old Swede completed a hastily arranged expedition, including a 21-day catamaran voyage across the Atlantic, to a U.N. conference originally planned in Santiago, Chile.

Ms Thunberg was met by a crowd of reporters but did not speak as she left the train.

"I successfully managed to sneak into Madrid this morning! I don't think anyone saw me ... Anyway it's great to be in Spain!" Ms Thunberg tweeted after leaving the station.

Thousands of activists from around the globe will simultaneously hit the streets of Madrid and Santiago on Friday to demand urgent action on the climate crisis from world leaders attending the COP25 summit.

The Swedish activist plans to join the main march will take place in Madrid on the sidelines of the UN climate conference, with a simultaneous rally in the Chilean capital, which had been due to host the 12-day gathering but was forced to pull out due to massive protests.

The Lusitania, which runs daily, is the only direct train link between Lisbon and Madrid and takes nine hours to travel overnight between the capitals.

The annual summit kicked off on Monday with a call from UN chief Antonio Guterres not to be the "generation ... that fiddled while the planet burned".

Thunberg is due to take part in a mass march and make a speech later in Madrid.

The talks come as scientific evidence mounts about disasters that could ensue from further global warming, including a study commissioned by 14 seafaring nations due to be published Friday that predicts that unchecked climate change could devastate fishery industries and coral reef tourism.

That could cause hundreds of billions of dollars in losses by 2050, says the report, adding that limiting global warming would lessen the economic impact for coastal countries, but that they also need to adapt to ocean changes.

The presence in Madrid of Thunberg was expected to shift the attention to demands for greater action by non-governmental organizations and a whole new generation of environment-minded activists.

Past appearances by the 16-year-old have won her plaudits from some leaders — and criticism from others who’ve taken offense at the angry tone of her speeches.

An advocate for carbon-free transportation, Ms Thunberg traveled by train overnight from the Portuguese capital, Lisbon, where she arrived earlier this week after sailing across the Atlantic Ocean from the United States by catamaran.

That became necessary after a sudden change of venue for the COP25 summit following a wave of anti-government protests that hit Chile, the original host.