For many decades the world witnessed mass displacements. Migration can be either voluntary or forced depending on the reasons. Mass migration can be also due to climate changes that harden the living conditions. Since there is a bidirectional nexus between migration and environmental degradation, the dramatic increase of refugees, asylum seekers, and immigrants greatly affect the environment and conservation efforts. Globally, the movement of people has caused different types of ecosystem changes including deforestation, water, and air pollution, as well as increased waste. Furthermore, as a two-edged sword for conservation, urbanization and growing population cause increasing per capita demand for energy, goods, and services. In this chapter, migration and sudden-onset and slow-onset hazards, the correlation between migration and environmental degradation, environmental and economic effects on the destination, as well as the role of government during migration processes will be analyzed.