" It also includes those who experience acute, sudden displacement due to natural disasters. These groups would also include "some sociological characteristics of refugee movements: involuntary flight and vulnerability.which result in great hardship for displaced persons as well as the receiving community" (Surkhe, 1994). By some accounts, social disruption and global refugee movement related to the impacts of climate change could potentially manifest on an unprecedented scale. Though environmentally induced migration has been a feature of human adaptation since the beginning of history, there seems to have been a qualitative shift in its dynamics since the 1990s: ". the situation in the mid 1990s with respect to such movements would appear to differ somewhat from the historical experience in a number of ways: the scale and pace of environmental change has increased substantially; differences between countries in ability to cope with these changes have increased; whereas in the past the migration destination options for environmental migrants have overwhelmingly been to move within their country of origin, international destinations are of increasing significance." (Graeme, 1996).
Norman Myers, a fellow at Oxford University, stresses that "the consequences of large numbers of environmental refugees would be among the most significant of all upheavals entrained by global warming." In 1995, the number of global environmental refugees was estimated at 25 million (Myers, 2005). By 2050, he estimates, about 150 million people (1.5 percent of the total projected world population for that year) will be displaced by the effects of climate change, as sea levels rise, agricultural systems are destabilized by deforestation and drought, and extreme weather events proliferate (Myers, 1993). Other ecologically-based phenomena, such as Peak Oil and geopolitical conflict over scarce resources, could further accelerate this process.