Human geography student Andrew Alvedro, who chose to represent Spain, said there is an "air of anxiety" among young people, but also "a sense of disillusionment."
"When I said to some of my friends I was going to an event like this, they said 'what's COP?' - that's a bit concerning," he said.
"I think that kind of shows some of us are just sticking our heads in the ground."
He added he is "cautiously optimistic" about progress in tackling climate change.
"We know the science, we have the technology to deal with this crisis and yet instead of dealing with it, we're going in loops and circles," he said.
"We need to sort out the politics because the science has already worked itself out."
This year marks a decade since the landmark climate agreement was struck at COP21 in Paris, in which countries pledged to try to restrict the rise in global temperatures to 1.5C.
However, UN Secretary General António Guterres has warned that "overshooting" 1.5C is now inevitable, and the limit was breached in 2024 for a whole year for the first time.
Nour El Imane Boubekeur, who studies French and English law, represented her home country of France at the "Mock COP".
"I'm feeling pretty anxious but also I have some hope in humanity," she said.
"We managed to do big agreements like the Paris agreement of 2015, so I'm still hoping we're not completely lost."
"We can still make some changes but we need to make those changes right now if we don't want to live in a nightmare."