The individual or combined effects of climate change are likely to trigger mass human movement both within and across international borders. The United Nations High Commissioner for Refugees (“UNHCR”) predicts that between 50 and 200 million people may be displaced by 2050. Thus, the human impact on the environment is creating a new kind of global casualty for the twenty-first century—an emergent class of environmental migrants. The exact number of individuals cannot be predicted as scholars and international agencies provide varying statistics depending on underlying methods, scenarios, time frames, and assumptions. Many authors challenge the concept of climate change as a primary cause of forced displacement. Some authors even refute the existence of “environmental migration” because of the problem of multi-causality associated with the issue. They claim that the decision to move in most cases depends on a combination of other complex socioeconomic factors. In this context, this Article first examines the possible link between environmental change and consequent human migration. It shows how the major impacts of climate change play a substantial role in triggering human migration. Then it analyzes the types of environmental migration found in the literature on causes and extent of movement. Providing an overview of predicted numbers and figures of environmental migration, this Article also analyzes debates associated with environmental migration mainly based on the problem of multi-causality to show the diversity and complexity of issues related to environmental migration. Finally, this Article argues for recognition of and protection for migrants forced to move to safer places due to certain direct impacts of climate change, notwithstanding the existence of multi-causality.