On climate change and migration

The American law blog The Volokh Conspiracy is an unusual place to find guest blogs about migration driven by environmental change, but Matthew Kahn, author of the book Climatopolis does have a guest post there. He argues--as he does here, for instance--that migrations triggered by climate change need not be catastrophic, and in fact can be quite manageable or even net economic pluses. A central point of his analysis is that all cities will not be effected equally.

Not all cities will suffer equally from climate change. There are over 300 major cities to choose from in the United States. A city such as Seattle may suffer much less. An implicit assumption throughout Climatopolis is that there will always be some safe area where our cities can thrive and we can migrate to. If the entire 7 billion people on the planet lived at Hong Kong’s density then we would need 1.1 million square kilometers of habitable land. This represents just .7% of the world’s land mass.

Suppose that California’s coastal cities suffer greatly from climate change due to the combined punch of sea level rise, hotter summers, drought and rising electricity prices. Self interested households will see that California cities are no longer great places to live and they will “vote with their feet” and migrate to other cities that have suffered less from climate change or perhaps even gained due to warmer winter temperatures.

[. . .]

Our ability to migrate means that urban places can suffer while urban people continue to prosper. Within the New York City metropolitan area, New Jersey employment centers may gain if Southern Manhattan and Wall Street are under siege from sea level rise. Land owners in Southern Manhattan will suffer but workers at downtown Goldman Sachs would not.

Kahn even suggests that these migrations, from areas heavily impacted by climate change to areas not-so-heavily impacted, could through the reallocation of labour into more vibrant and/or rejuvenated environs. If the proper human connections exist, of course.

Growth economists have long argued that human capital (attracting and retaining the footloose, skilled) is the key for a nation or a city to enjoy sustainable growth. If a city such as Los Angeles loses its quality of life edge, then the skilled will move elsewhere and firms will be less likely to move to Los Angeles. Similar to a neighborhood with high crime or bad schools, local real estate prices will fall. The owners of such assets will bear the incidence of this “new news”. While real estate values would decline in cities deemed to be increasingly at risk, there are other cities that could actually experience a windfall. Today, you can trade one home near UCLA for 100 Detroit homes. In 2070, will this exchange rate still hold or will there be parity?

[. . .]

Does this same optimism hold in the developing world? In the United States, there are a large number of cities scattered across various geographical regions. In other nations such as Bangladesh, there is unlikely to be the same menu to choose from. As “environmental refugees” seek out safer havens they may cross political boundaries into nations where they are not welcome. Developed countries could ease adaptation in the developing world if they loosen immigration restrictions. Migration also represents an upfront investment that requires resources. The poorest of the poor may be unable to move and not to have the information or social networks concerning potential beneficial destinations.

I agree with Kahn to a certain extent. Back in June 2009 I blogged about climate change-driven migration in West Africa, noting how there were already well-established traditions of migration to and from the Sahel to the West African coast, and these these migrations played a significant role in economic growth in littoral states like Ghana and Côte d'Ivoire. Could a substantial migration of skilled Californians rejuvenate a Detroit notable for a decent locatino and very low real estate prices? I don't doubt it. If climate change-driven migration isn't a sudden process, but rather takes place on time scales on the order of decades, it needn't be unmanageable.

But. Kahn's analysis assumes that there is little possibility catastrophic runaway change with effects as outlined by Sublime Oblivion's Anatoly Karlin at the link previous, or that if it does happen the consequences will be manageable. This strikes me as optimistic. Le monde diplomatique observed that in 1998 the expected influx of very large numbers of Kosovar refugees into Albania threatened to destabilize an already shaky economy, while in 1999 the consequences of the Kosovo catastrophe weighed heavily on the entire western Balkans region. If, say, the Netherlands is significantly flooded, what would happen? Where would the Dutch go? What would happen to the Eurozone economy? If California enters a long period of economic decline precipitated by a worsening climate, what will happen to the American economy? If Shanghai floods, or has to protect itself, what will happen to the Chinese? Et cetera. The loss in infrastructure investments alone, never mind symbolism/morale, would be serious indeed.

The political and social consequences of migration of this scale also need to be considered. In Côte d'Ivoire, the migrations from the Sahel were eventually used for political and economic reasons to trigger xenophobia among the Ivoiriens de souche, leading to more than a decade of civil war and division. The decades of net migration from the Sahel did benefit Côte d'Ivoire, but the country experienced a meltdown nonetheless. The factor of xenophobia is less of an issue in some countries and regions than in others--the American population may be mobile enough to cope--but it still has to be considered. In the example of Bangladesh, source of perhaps tens of millions of migrants in India who often act as cheap labour, fears of Bangladeshi immigrants' links to terrorism and flee Assam won't help things in the case of future mass migrations.

And then, there is the question of what people who need to migrate but don't have the connections necessary to successfully migrate--or even migrate at all--will do. What will be done?