A widespread view that is gaining ground is that climate related migration could evolve into a global crisis by displacing a large number of people from their homes and forcing them to flee. Christian Aid postulates that a billion people could be permanently displaced by climate change related phenomenon such as droughts, floods and hurricanes (Christian Aid 2007). The fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC) mentioned the “potential for population migration” due to increase in the number of areas affected by droughts and an increase in the intense tropical cyclones activities (IPCC 2007: 18). In particular, it seems likely that significant numbers of people will be displaced, either temporarily or permanently, from their homes as a consequence of global warming (Stern 2006). Available scientific evidences indicate that a large number of people might be displaced due to climate change. However, much of the literature on this issue refers to the question of whether the   people forced to migrate as a consequence of climate change should be described as climate refugees. There is no internationally agreed definition of the term “climate refugee” and the extent to which these displaced persons constitute a separate identifiable group. Although it is now widely recognised that climate change will significantly adversely affect India, there are few studies available on how climate change is going to affect the migration of people. It has been asserted that 70,000 people out of the 4.1 million living in the Indian part of the Sundarbans islands would be rendered homeless by 2020 (EPW, 6 June 2009).
Climate change might result in two types of displacement and migration in India. First, increased migration is likely within India due to the effects of climate change such as drought, desertification, sea level rise, water scarcity and low food productivity, and melting glaciers. Second, climate change might lead to increased flow of migrants from neighbouring countries due to the accelerated effects of climate change. Although, the available studies in India do not provide any concrete findings on these effects, scientific evidence on   climate change support the phenomenon of climate­induced migration.

Climate change might lead to increased flow of migrants from neighbouring countries. As many as 120 million people could be rendered homeless by 2100 both in India and Bangladesh due to sea level rise and given the proximity of Bangladesh to India much of the people will end up as migrants in Indian cities which are already facing resource scarcity (Rajan 2008). More than five million people in Bangladesh are living in areas which are highly vulnerable to cyclones and storm surges (McGranahan et al 2007). Flooding currently displaces 5,00,000 people every year in Bangladesh (Warner et al 2009). It has been estimated that 20 million people are annually migrating from Bangladesh to India (Brown 2007). The future effects of climate change are likely to increase the flow of population from Bangladesh to India. Myers (2002) argues that climate refugees from Bangladesh alone might outnumber all current refugees worldwide. He projected that 26 million refugees will come from Bangladesh. One of the earlier studies by Homer­Dixon (1994) concludes that Bangladeshi migrants have expanded the population of neighbouring India by 12 to 17 million over the last 40 years caused by environmental scarcity. Another study finds that Bangladesh is currently faced with severe crisis of land and water, caused by population growth, environmental change and recurring natural disasters and the flow of migration from Bangladesh to India may increase at a faster rate (Alam  2003).

However, there are still significant gaps in several areas. First, the international community is yet to recognise this new category of migrants. There is no consensus on the definition and the status of climate refugees owing to the distinct meaning the term refugees carry under international law. Second, there are still gaps in understanding how climate change will work as the root cause of migration. Third, even if there is recognition of climate refugees, who is going to take the responsibility to provide protection and assistance? Fourth, more emphasis has been given to international migration due to climate change. But the people may also move to other places within the countries. There is a need to recognise the displacement of people within the countries so that proper action can be taken to address their problems.Current knowledge based on the relation between climate change and migration of people is still limited. There is a need for a better understanding of the relation between climate change and migration. The international community should not be distracted by the semantic differences  between words to describe the status of people migrating due to climate change. We need to recognise the problem and appropriate strategies and measures to assist the people displaced by climate change should be devised to effectively deal with the problem.