We can distinguish two general causes of internal displacement worldwide: 1. the impact of threats to and ensuing decline in the level of human security below that needed for normal existence in the homeland territory, 2. administrative compulsion to leave the current place of residence. Every year, at least tens of millions of people on all continents are forced to leave their places of residence. The predominant cause is the occurrence of natural disasters, creating the most dynamic category of internal displacement. According to IDMC estimates, natural disasters expelled 42 million people from their homes in 2010 and 14 million people in 2011. Many cases of internal displacement are associated with the accelerating dynamics of climate change, which is a much more long-term phenomenon. The causes of this kind of displacement are the desertification of soils and potential rise in sea level. The aim of this paper will be to determine the impact on several areas of human security of long-term environmental change and the displacement it causes.