Climate Change and its Implications for Human Migration and Health

Manuel Carballo and Chelsea Smith

Climate change, and especially global warming, can be expected to affect life and human society in many ways. Combined with the growing, albeit highly regional, global population growth it will become one of the main precipitators of migration, forcing millions of people to leave their homes and seek security in more climatically friendly places. Migration has always been one of the key ways in which human beings as well as other animals have responded to adverse environmental conditions. If and as warming trends continue to provoke greater and faster desertification and drought in some regions, and rising sea levels in others, the pace of migration as an adaptive response will inevitably increase. Some estimates suggest that by the middle of the 21st century as many as 200 million people could become “climate refugees” as a direct result of rising sea levels, heavier and more frequent flooding on the one hand and more intense droughts on the other .

The push of climate change is nevertheless likely to be felt more in some regions than others irrespective of the nature or degree of climate change. Tragically it will probably be the most economically poor parts of the world that will have the greatest difficulty coping technologically with climate change in ways that would make it less necessary for people to move . They will probably continue to have the least access to the technological resources that might be capable of reducing or mitigating the effects of global warming. Many already live in climatically challenging regions where water is either already in short supply or poorly explored, and where the quality of life is poor. Others are trying to survive in coastal and river delta areas where rising sea levels could easily make human settlement impossible . Some estimates have referred to one million or more people being displaced for every centimeter of rise in sea level and in Asia where three-quarters of the world’s population and two thirds of the world’s urban population currently lives in low-elevation coastal zones the impact of continued warming could be felt within the next two decades.

Where people will choose to move is not clear, but a number of options can already be foreseen. Each of them stands to carry with it different political, societal and health implications that will have to be taken in to account and planned for at an international as well as a national level. Cities have long been seen by human beings everywhere as havens of survival and the massive scope of current urbanization is due more to migration than to natural increase of urban populations. Unfortunately many if not most major cities in developing countries are already unable to absorb the people arriving in them and provide even the basic water and sanitation services required for healthy life. If the rate of urbanization is further pushed by climate change related displacement these resources will become even more challenged. Pollution in already polluted cities will grow and further contribute to already poor public health.

How far people will be willing and able to move is not clear but climate change could push millions of people to seek safe haven across national borders and in doing so further intensify the already fast pace of international movement and the resistance to migration and migrants that is now taking serious political as well as social dimensions. Policy makers in many parts of the world are today talking as much about deportation as they are about integration, and throughout much of the world, serious legal barriers are being raised to prevent not only new immigration, but also make it more difficult for migrants to resettle and be socio-economically constructive.

Other complications will emerge as well. Migration is rarely simple and when it involves vast numbers of people it is even less so. It involves serious decision-making on the part of those who move. In most cases it calls for difficult choices as to what to take and what to leave behind. In extreme cases it also calls for even more difficult decisions about who to take or leave behind because not all people are able to move easily and in the heat of forced movement some are inevitably seen as slowing others down and making prospects for success less evident. Nor is everyone likely to be willing to move. Some such as the elderly may be afraid of the future elsewhere or too attached to the past and places they know. Family separation and disorganization will be inevitable and will bring with it serious psychosocial challenges. Many people will also be forced into areas that openly reject and make life difficult for them as unwanted migrants. Even today when migration is by no means as pronounced as it will become in an era of massive climate change, countries are busy setting up detention centers that are designed, among other things, to make the life of “irregular” migrants sufficiently difficult that they will not want to come back. In the process they are already exposing detainees to a range of health threats that they risk taking back with them once deported. Climate change-related migration will occur at a time when the struggle for scarce resources such as water, land and energy will assume an even greater socially and politically charged character.

Migration, moreover, is never without its implications for public health and mass migration due to climate change will inevitably introduce the potential for threats to those who move and those they meet and live with. The nature of the health threats will vary according to where people are moving from and to. Some will be moving from areas with a history of tropical diseases that are not common in the areas migrants go on to move into and where little if any herd immunity has developed or where local medical practitioners are not familiar with the symptoms, diagnosis and treatment called for. Conversely other people may be forced to move to zones where they too will be exposed to health threats they have not encountered before and which they have no experience with from either a preventative or a therapeutic perspective.

In summary, climate change of the order and magnitude that is predicted will produce some of the most massive forced displacement ever seen. The implications of this for social and political stability will be far-reaching. As far as public health is concerned, the situation will become even more challenging. Not only will there be a widespread movement of new health problems and diseases, but this will happen in an social and political environment in which dealing with those challenges could in itself become difficult.

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Additional Links:
WHO Climate Change and Human Health
Red Cross/Red Crescent Climate Center
Centre on Global Change and Human Health
Wikipedia Climate Refugees
The Climate Change and Human Health Integrated Assessment Web by Johns Hopkins University
The Stern Review on the Economics of Climate Change
Intergovernmental Panel on Climate Change