Climate change is a contentious issue. The validity of even the term as well as the science associated with it is in dispute although the near universal membership of nations to the UNFCCC convention clearly signifies the recognition of the issue. There is also no international consensus on the terminology used to describe people whose movements are connected to environmental change, whether gradual or sudden, as from natural disasters. According to the International Organization for Migration (IOM), environmental migrants are “persons or groups of persons who, for compelling reasons of sudden or progressive changes in the environment that adversely affect their lives or living conditions, are obliged to leave their habitual homes, or chose to do so, either temporarily or permanently, and who move either within their country or abroad” (IOM 2007, pp. 1-2). It is rarely possible to isolate people migrating in response to environmental factors outside of disasters. What is likely though is that environmental change will continue to compel people to move or affect those who choose to remain.

While there are no reliable figures of environmental migrants, more than 42 million people were displaced worldwide by sudden-onset natural disasters in 2010 (Yonetani 2011). The Asian Development Bank has estimated that in the Asian and Pacific region alone about 31.8 million people were displaced by climate-related disasters and extreme weather in 2010, including more than 10 million in Pakistan owing to massive flooding (ADB 2012). As population figures grow, people are also increasingly living in areas of higher vulnerability. When a disaster strikes, immediate assistance is provided by communities themselves, the government of the affected country or the international community depending on the size and scale of a disaster, the capacity within a country to respond to it, and the willingness to receive assistance. Long-term solutions for populations regularly displaced or affected by natural disasters must be developed by local communities themselves in coordination with local government and development partners.

There is an equally significant debate about the primacy of environmental change as a motivator for people to move as there is regarding terminology. While the debate over the causes, culpabilities, liabilities, and responsibilities regarding climate change continues, millions of individuals are affected yearly by natural disasters, some of which may be attributable to environmental change.

Providing protection and assistance to environmentally-displaced populations poses several challenges: determining whether the migration was forced or voluntary, temporary or permanent, and if the durable solution requires crossing an international border (Boano and others 2008). If this international border is disputed or not demarcated, greater complexities arise. Still, it is important to note that despite the focus of many potential or actual movements across international borders, the vast majority of climate change-related displacements are expected to occur within the borders of a country (IOM 2011).

Proposals to create a new legally-binding protection mechanism for environmentally-displaced populations are being discussed in different forums, but a consensus on the matter is unlikely in the near future as this is contingent upon establishing a direct causal linkage between population movement and environmental change. In practice, this will prove very difficult to demonstrate. As Graeme Hugo has observed: “Population mobility is probably best viewed as being arranged along a continuum ranging from totally voluntary migration…to totally forced migration”, as opposed to solely residing within any one category (Hugo 1996).

In the context of Bangladesh similar complexities on the relationships between environment, climate change and migration have been noted:

“Migration is a multi-causal phenomenon: even in cases where the environment is a predominant driver of migration it is usually compounded by social, economic, political and other factors. The ‘decision’ to move or to stay is highly complex and depends on available resources, social networks and the perceived alternatives to migration. In turn, these depend, inter alia, on the individual, social and even cultural ability to cope with and adapt to climate shocks and stresses, including the particular vulnerabilities faced by women, children, the elderly, the disabled and the extreme poor. Therefore, just as the environment is only one among many factors that drive migration, migration is also only one among many possible responses to environmental change” (Walsham 2010).

While significant attention is centered on those who migrate, at least in part, due to environmental change it is important to remember that migration can only be an adaptation strategy when resources are available to migrate. Those left behind may, in fact, be the most vulnerable.