Rapid advancements in artificial intelligence (AI) have created new opportunities to solve environmental concerns, especially those pertaining to ecological preservation and sustainability. This chapter looks at how agentic AI could encourage sustainable practices and foster environmental stewardship by autonomously identifying, managing, and lowering ecological hazards. Because agentic AI may function as autonomous agents with decision-making capabilities, it provides unparalleled advantages in complex simulations, real-time data processing, and proactive interventions. From optimising energy consumption to managing waste and preserving biodiversity, AI-driven systems have the potential to fundamentally alter sustainability and environmental governance. After going over the fundamentals of agentic AI and its uses in environmental science, the chapter delves deeply into how it can be used to mitigate climate change, manage resources, and reduce pollution. Additionally, it looks at how agentic AI might improve environmental policy decision-making, predictive analytics, and ecosystem modelling. AI-powered technologies for ecological system optimisation, predictive modelling, and real-time monitoring are introduced in the methodology section. The efficacy of AI applications in actual environmental scenarios is illustrated through experiments and case studies. The discussion of future developments in agentic AI concludes by outlining the difficulties and moral issues that need to be resolved in order to implement AI in environmental stewardship in a balanced manner.