With double-digit scores across Europe's biggest countries including a stunning 20 per cent in Germany, the Greens bagged record gains in European elections on Sunday with younger voters leading calls for action to halt global warming.
The environmental party doubled its score in Germany from the last EU elections in 2014, knocking the Social Democrats off their traditional second place.
In France, the Greens came in number three with 12 percent, while in Austria, Ireland and the Netherlands, they garnered double-digits.
With the two main traditional EU blocs - the conservative EPP and the centre left Social Democrats projected to lose ground, the Greens could end up as kingmaker in the European Parliament.
German top candidate of The Greens party for the European Parliament elections, Sven Giegold. Source: AAP
"This is a Sunday for Future," said the Greens' lead candidate in Germany Sven Giegold, in a nod to the "Fridays for Future" school strikes by students sounding the alarm on the climate crisis.
His counterpart in France, Yannick Jadot, also hailed it as a "green wave in which we are the main players."
France's Prime Minister Edouard Philippe acknowledged the "message about the ecological emergency".
"Everywhere in Europe, our citizens and in particular the youngest are asking us to act with determination and that's what we'll do in France and in Europe," he said.
'Prove you mean business'
The momentum for the Green surge had been building up over months as the strikes started last November by Swedish activist Greta Thunberg, 16, not only refused to lose steam but caught the imagination of youth across the world.
In a major mobilisation on Friday, tens of thousands of students rallied, with some calling on their parents to tick the box for the environment at European polls this week.
Youth gather to draw attention to climate change in front of the European Parliament, the day before the European elections. Source: AAP
Cheering Sunday's results, a leading student activist in Germany Luisa Neubauer wrote: "The European elections show that we're not only bringing the climate crisis to the streets but also to the ballot boxes. This should give food for thought to those who have in the last month laughed at 'youth engagement'."
Under the 2015 Paris deal to limit global warming to well below two degrees Celsius above pre-industrial levels, the 28-nation EU has pledged to cut greenhouse gas emissions by at least 40 percent by 2030, compared to 1990.
But many scientists and climate activists say Europe and all other major economies must sharply raise their ambition.
The UN Intergovernmental Panel for Climate Change warned in October that warming is currently on track towards a catastrophic 3C or 4C rise.
Biggest challenge
In Germany, the climate crisis has exposed a generational split, with adults and the elderly accused of hanging on to their polluting diesels while youngsters are urging change by going on school strikes.
Stunned by the Greens surge, the parties in Germany's governing coalition vowed to take on the challenge.
Markus Soeder, who heads Chancellor Angela Merkel's Bavarian allies CSU, declared the environmental party as its main competitor.
Climate activists hold up placards outside the European Parliament during the EU elections. Source: AAP
"The biggest challenge of the future is the intensive debate with the Greens," he said, adding that "old measures that we had before, are no longer valid".
Underlining that his party is struggling to win over young voters, he added that "we must work to be younger, cooler and more open".
In the days running up to Sunday's vote, Ms Merkel's party had also come under fire from prominent YouTuber Rezo whose blistering online attack over climate policy went viral.
The CDU struggled for days to find a response before finally on Thursday seeking dialogue with him.
Raising the ante, Rezo, along with 70 other influential YouTubers, instead published an open letter urging people to shun the CDU, the SPD and the AfD at the polls.
Early results suggest that around one in three under 30s voted Green, while only 13 percent picked the CDU in Sunday's EU vote.
A poll by Infratest meanwhile found that one in three first-time voters gave their vote to the Greens.
