In 2017, at age 15, Margolin founded the youth climate action organization Zero Hour with Nadia Nazar. She serves as the co-executive director of the organization. Margolin co-founded Zero Hour in reaction to the response she saw after Hurricane Maria in Puerto Rico and her personal experience during the 2017 Washington wildfires. She has garnered some notoriety as a plaintiff in the Aji P. v. Washington case, suing the state of Washington for their inaction against climate change on the basis of a stable climate being a human right. Her writing about climate change has appeared in many publications including HuffPost, Teen Ink and CNN. She was part of Teen Vogue’s 21 Under 21 class of 2018. In 2018, she was also named as one of People Magazine's 25 Women Changing the World. Margolin is a member of the Junior State of America. In September 2019, Margolin was part of a youth group that sued Governor Jay Inslee and the State of Washington over greenhouse-gas emissions in the state. Following this lawsuit, she was asked to testify against them as part of a panel called "Voices Leading the Next Generation on the Global Climate Crisis", where teenagers involved in climate change were able to make their case. The youth in this lawsuit were concerned with the Washington Governments lack of action surrounding climate change, implying that they are denying the younger generation a constitutional right to a liveable environment without these environmental issues they are facing. Margolin co-founded the Zero Hour Organization in 2016. This group of youth activists is focused on the lack of action being done by the officials around the world in terms of climate change. Margolin claims, "There is a crisis happening, but no action is being taken. This organization is a non-profit international organization whose goal is to educate people about the climate crisis and get more people involved in activism. Their first goal was to create a national mass day of action in order to get more youth involved in fighting for the health of the planet. By using #thisisZeroHour, the dedicated youth in this organization hope to send out the message that there is no more time to waste, and action must be taken as soon as possible to combat climate change". In their mission statement they explain "We believe that every individual, from every community should have access to clean air, water, and public lands. We believe in putting the needs and health of our communities before corporate gain." along with other goals they are hoping to get other people around the world involved in fighting for. They try to focus "on educating people about what the climate crisis is and how to be an activist to help the issue".
