Support for the Greens has surged in Switzerland's election, moving politics to the left and putting environmentalists in the mix for a seat in the broad coalition that has governed the country for decades.
The far-right Swiss People's Party (SVP) remains in first place, according to projections after the parliamentary election on Sunday.
However like other big parties the SVP lost ground as environmentalist parties seized on voters' concerns about climate change to shake up the political establishment.
"It is not a green wave, it is a tsunami, a hurricane," said deputy Greens leader Celine Vara, who won a seat in the upper house of parliament for Neuchatel canton.
Far from the sea, Switzerland is especially vulnerable to climate change as temperatures in the country are rising twice as quickly as the global average.
The SVP, which won a record number of seats in 2015 amid Europe's refugee crisis, slipped 3.6 points to 25.8 per cent while the Greens' share surged 5.9 points to 13.0 per cent of the vote for the lower house, according to a gfs.bern projection for broadcaster SRF.
The smaller, more centrist Green Liberal Party (GLP) advanced to 7.9 per cent, bringing the two parties' combined strength to nearly 21 per cent should they overcome policy differences and decide to join forces.
Together they gained 26 seats in the 200-seat lower house, potentially putting them in line to take one of the seats in the seven-seat cabinet, the Federal Council.
Changing just one member of the cabinet would be a political sensation. The Greens have never had a seat in the federal government.
The centre-left Social Democrats remained second on 16.6 per cent and the centre-right Liberals (FDP) third at 15.3 per cent, but the Greens leapfrogged the centrist Christian Democrats (CVP), which has one seat on the Federal Council.