As the impacts of global climate change increase, threats to environmental, human and international security will emerge. Coping with climate change has become essential to managing these threats. This essay explores the emergence of ecosystem-based adaptation (EbA) as one of the most important means by with to cope with climate change. The notion of EbA begins from the perspective of ecosystems: ecosystems themselves can help societies adapt to climate change, thereby limiting threats to human security and potentially helping to protect domestic and possibly international peace. What are the arguments for and against EbA? Who favours EbA? What does EbA mean in practice? In this essay, we point to findings of nongovernmental organizations (NGOs), governments, intergovernmental organizations (IGOs), and scholars to help answer these and related questions. What is clear is that the more that climate changes, the more important all forms of adaptation, including EbA, will become.