Responding to global climate challenges, states are pursuing mitigation and climate adaptation policies, which requires involvement of all actors ranging from global institutions to the public. This article aims to evaluate green waste practices of nongovernmental organizations in terms of the possibility of incorporating these practices into climate mitigation and adaptation policies. The study focuses on two nongovernmental organizations that have been involved in waste management for more than 10 years and has examined the online posts of these organizations to determine the prevalence of nine green waste practices, as well as subscribers’ interest in them. The posts are classified using modern machine learning methods. To train a machine learning classifier, we used a dataset for detecting mentions of green practices in social media posts. The study demonstrated that environmental nongovernmental organizations engage hundreds of people in green practices aiming to reduce anthropogenic climate impacts or adapt to climate change. The often-mentioned practices (separate waste collection, recycling, and other adaptation activities such as promoting responsible consumption or refusing purchases) can be included in governmental policy. Subscribers are aware of ways to reduce consumption and manage wastes responsibly and they can share their experience with the communities gaining the support of the government. The proposed recommendations are related to broad engagement of grassroots initiatives in climate policy implementation.