Incredible scenes unfolded across Australia last week when thousands of students skipped school to protest after Prime Minister Scott Morrison urged kids not to take part in the event.
In Sydney and in Melbourne, huge crowds of students filled public spaces shouting at the top of their lungs.
They brought banners and signs reading "I've seen smarter cabinets at Ikea", "I'm sure the dinosaurs thought they had time too", "There's no Planet B" and "We'll be less activist if you'll be less shit".
On the Q&A panel, former South Australian Liberal senator Amanda Vanstone said she was saddened by Marco's perspective.
"It makes me sad to hear a young person say 'people don't care about my future'," Vanstone said.
"Both the major parties have got policies. They disagree about them. They both have policies. Emissions are coming down. Some people want them faster. But to just give the impression to young people that nobody cares I think is a bad thing."
In response, Marco said he was sad too — "sad to see the political inaction on climate change".