Evelyn Acham, a Ugandan activist with the Rise Up movement in Africa, said the issue had spurred young people to abandon other parts of their lives to focus on pushing for action.
Ms Acham was speaking ahead of tens of thousands of young people taking to the streets of Glasgow in a bid to pressure world leaders to ensure firm action is taken as a result of COP26.
Another activist, American Sophia Kianni, also said “not much” has been done at previous Cop meetings before the one ongoing in Glasgow, but said there should be “cautious optimism” for a positive outcome that pledges to keep the rise in global temperatures below 1.5C.
Speaking on BBC Radio Scotland’s Good Morning Scotland programme, Ms Acham said: “The young people going out there to march gives us hope.
“The future belongs to those young people, because they still have a lot of time, they haven’t achieved a lot, but the older generation have already achieved so much and (climate change) probably won’t be so much their problem.
“But young people still have work to do, they still have school to do, they have a future to build, so this is our concern.”
She added: “So many young people have given up school to become full-time activists, some have given up work, some have given up going for a masters degree, just because they’re seeing the urgency of this.
“To the young people, this is very urgent, because we need to settle down and do other things, we need to go back to school, we need to focus on the future.”
Ms Acham added that young people continued to take to the streets across the world because “we do not have a choice”.
Campaigner Greta Thunberg, activist Vanessa Nakate and other young campaigners, as well as local trade unionists will speak to crowds at the end of the march through the city on Friday where the UN summit is being held.
Ms Kianni, who is a member of the UN Secretary General’s climate change advisory panel, said young people’s voices have historically been excluded from high level discussions on the climate.
“We don’t have tangible decision-making powers and we’re not built into these spaces the way that we should be,” she said.
“I’m hopeful because of people like you, Evelyn – I’m hopeful because of the people on the streets who are going out and striking and making sure our voices are heard. But as far as the processes inside the building go, I’m not too sure yet.
“I think at the end of these two weeks we’ll see whether or not any progress has been made, but time after time we’ve seen at Cop that not much has been done, and so I think we should have cautious optimism, but we shouldn’t be overly optimistic.”