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Does migration also cause climate change?

Dilip Ratha's picture

Climate change has historically pushed people to migrate. There is widespread belief - fear? - that rising sea levels will force millions of people to migrate out of Bangladesh and Vietnam. If that happens, these migrants will spill into neighboring countries many of which are unlikely to be ready to take on migrants. Many will also sooner or later spread into far away countries in Australia, Asia, Europe and North America.

What concerns me more is that this simplistic viewpoint has very little factual analytical backing. Data on migration trends over time are bad. Data on climate change as they relate to migration are even worse. What is worse, migration experts are not necessarily talking to the experts on climate change.

A conversation with Vijay Jagannathan, a water expert and good friend, alerted me to another low probability but high impact event - the melting of the glaciers on the Himalayas. If that happens - the probability is low, but if it does - China and India on either side are likely to be affected, posing more serious geopolitical risks than the rising sea level.

A starting point for analytical work in this area would be gathering relevant data on migration - probably at zipcode level from household surveys wherever they exist - and link that to climate change data which are more likely to exist in many countries. (Recall the saying that, unlike an economist, the weatherman is usually right about the past!)

While every one is thinking about how climate change affects migration, I wonder if we should also worry about how migration affects climate change. For one, if harsh regions are populated through immigration, does that deplete resources? Does that contribute to global warming?


Submitted by Cristina on
Interesting question. How about through the carbon footprint of all the air travel that migrants and their families now undertake? I was chatting about migration with a friend recently, and he pointed out that once upon a time, (lower-emitting sea) travel was so expensive that migration meant a decades-long, or even permanent, exile. Now it means only intermittent absences -- migrants leave expecting to return every few years or so, and in the intervening years, family members might fly (thus emitting CO2) back and forth to see them. There must be airline industry data on this. Another aspect: insofar as migrants generally move to take advantage of opportunities in higher-carbon economies, there must be some correlation between migration and climate change. Surely not a direct causal link, though. Finally: your blog is great!

Submitted by Shabani on
I was walking thought the UNEP Africa: Atlas of Our Changing Environment that talks about the origin of the Darfur conflict. The report says "The combination of decades of drought, desertification, and overpopulation are among the contributing factors that led nomads searching for water to drive their livestock south into regions mainly occupied by farming communities." It is clear that the factor that caused migration was droughts; desertification and overpopulation, and then come the depletion of resources in the areas where the migrants decided to live, consuming more of the scarce resources they find on their way, which contribute to global warming. In this case, it is not migration that causes climate change, but the cause of the migration causes climate change. In Dagahaley and Hagadera refugee camps in Dadaab, Kenya, where migration was caused by conflict itself, there are also visible changes in landscape caused by Somali refugees on the camps. Everywhere migration causes climate change; there is a cause for that migration that, in my opinion is the real cause to climate change.

Submitted by Greg White on
Thank you for this posting. There is an ample literature on climate-induced migration. You're right to point out that some - not all - of it is "simplistic." There is good work, too, that is appropriately skeptical. (See work by Stephen Castles or Richard Black.) But that doesn't mean there isn't work being done or that climate experts are not engaging migration experts. Renaud et. al. 2007. Control, Adapt or Flee (UNU-EHS) is a good overview, as is this summer's CARE/CIESIN study In Search of Shelter. Thank you for your work! ~Greg White

Submitted by Christine Zarzicki on
I think that this question is very interesting and extremely relevant. There must be some sort of correlation between migration and climate change, however I think it is more a result of resource depletion than fear. While people are becoming more and more aware of global climate change and its adverse effects on various populations, I truly believe that people stay with their land or their "home" until the bitter end. For example, people in Vietnam remain in their country despite growing threats of natural disasters, such as flooding and landslides. They have opted to continue living their lives, however embarking on projects that prevent and preclude devastation. Also, in New Orleans Louisiana, in the after math of Hurricane Katrina, the community gathered together to restore the city to its original state despite the possibility that it may happen again. While many people are becoming anxious over the threatening nature of climate change and the natural disasters it produces, it seems that they will not let fear defeat them. Instead they remain with their land, doing anything possible to alter the course of fate. On the contrary, I think it is very possible that over utilization of land and natural resources in some areas of the world has led to changes in climate. As people migrate from these desperate terrains, they tend to overcrowd the nearest city, ultimately adding to the “carbon footprint” of that urban development. While I don't think fear of losing land influences people to migrate, I believe that once the land is depleted and useless, migration is the only option .

Submitted by James Eliscar on
First of all, I would like to thank you Dilip Ratha for bringing up the question in this reverse fashion. It is very true that scholars or practitioners work in the field of environmentally-induced migration and forced migration tend not to look at the question in reverse way.It is certain that the field of forced migration, data are lacking; a situation that is due for many different reasons. However, I have to say that there is enough data around to explain the problem and try to craft solutions. As regards to your fascinating question as to whether or not migration also cause climate change? To some extent, I will say yes, but will be quick to also say that the impact is minimal. Our actions, as we all know, have an impact on our environment. In doing our activities, we all leave our carbon footprint. It can be explained that climate change push people to migrate, but explaining that they continue polluting or their actions greatly affect the environment while seeking shelter farther inlands will not be an easy one, because many of those displaced by climate change do not have means to greatly impact the environment, in the process. Again, I appreciate your perspective on the issue. But, the impact of environmentally-induced migrants is very minimal and not consistent enough to impact our environment greatly, as do Western industrial countries and China.

Submitted by Saliha Dobardzic on
It is very interesting how the relationship between climate change and migration "cuts both ways," as I am finding out looking at the climate-induced migration in the Middle East and North Africa. (By the way, while it is true that much has been said about climate change and migration globally, the question of what role climate plays in migration regionally and at finer scales of resolution still remains largely unanswered, and we simply do not have a good picture of the current scale at which climate determines migration in many places. As a result, it is extremely difficult to generate expected migration scenarios based on climate change projections.) The question of how migration affects climate change is fascinating and unfortunately under-explored. We know that forced migration in some cases directly results in rapid and severe environmental degradation, such as deforestation seen in and around refugee camps, and rural-urban migration results in increased urbanization, affecting most visibly the urban microclimate. However, beyond such readily noticeable phenomena (which themselves warrant a more systematic inquiry), there is a plethora of different ways in which migration affects climate change that would be most interesting to explore...

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