U.S. President Barack Obama probably didn't have Chunyun in mind when he pressed for immigration reform during his recent State of the Union address. During China's annual spring festival travel season, or Chunyun, approximately 200 million Chinese -- give or take a few million -- make like salmon and return from the industrial centers on China's coast to their ancestral homes farther inland (with a few going against the flow from rural areas to the cities in which they or their families grew up). It's the world's biggest annual human migration, and 2013 promises to be a record-breaker: An estimated 3.4 billion journeys will take place in the roughly 40-day period around the Chinese New Year, more than ever before, and way up from 2 billion in 2006.
China's Chunyun is almost entirely domestic. But it illustrates the importance of allowing people to flow from poorer areas to richer ones. Under Mao Zedong's rule for most of the second half of the 20th century, it was very difficult for rural Chinese to move to cities. Liberalizing this system, thereby allowing poor farmers to find jobs in factories, has probably done more than anything else to drive China's economic growth over the past few decades. But the annual Chunyun -- the return to home -- also shows that migration is never a one-way street.
In the first State of the Union of his second term, Obama pledged to offer undocumented migrants a path to citizenship. Taking the initiative to erase the legal limbo that currently ensnares the more than 11 million "unauthorized immigrants" is more than just socially expedient -- it's also a savvy political move. The president's Democratic Party would ensconce itself firmly in public opinion as pro-reform, sticking the Republicans with three election-losing labels it will find hard to shake: angry, old, and white. And it makes cold, hard economic sense: One credible estimate put the gains from comprehensive immigration reform at $1.5 trillion over the next decade.
The dizzying logistics of both Chunyun and Obama's immigration reform ambitions only hint at the enormity of the migratory phenomenon. In 2000, there were only 150 million migrants globally; by 2010, that number had skyrocketed to 214 million, just over 3 percent of the world's population -- and that's just counting the international migrants. China alone has about as many internal migrants; globally, an additional 740 million people live and work far away from home, but inside their own country of birth. Roughly one in eight of Earth's 7 billion human inhabitants is a migrant. Across other parts of the globe, several smaller Chunyun oscillate to the rhythm of the seasons: between North America and Central America, from Germany to Turkey and back, and from the conurbations of the Arabian Peninsula to the villages of East Asia. The money sent back the same way helps the world go round: The sum of remittances sent home by migrants in 2010-- $440 billion -- constitutes about 1.5 percent of gross world product.
But for many on the receiving end of these migratory flows, these human incursions represent the clippety-clop of the Apocalypse. Didn't the Roman Empire -- the paragon of a dominant civilization weakening into collapse -- crumble under the pressure of swarming, hungrier peoples with scant disregard for its immigration policy? That period in history, from about A.D. 400 to 800, is so darkened by shudder-to-think retrospect that it is also known by its Wagnerian nickname, the Völkerwanderung. On a smaller scale, the trauma of ethnic displacement still haunts Serbian, Greek, and other Balkan nationals.
And -- cue the ominous orchestra -- these days the barbarians are motorized, most of them arriving by planes, trains, and automobiles. The fearful, nativist pamphlet writes itself. But the picture -- then as now -- is more subtle. In the 19th century, geographer E.G. Ravenstein -- himself a migrant from Germany to Britain -- proposed a set of laws of human migration. Arguably, the most relevant is "Every migration flow generates a return or countermigration," but the easiest to spot is his law that large towns grow by migration rather than by natural increase -- in other words, by migration rather than births.
Indeed, the ethnic composition of Europe's large cities is rapidly differentiating itself from those of their surrounding countrysides. Half the inhabitants of Rotterdam, Europe's biggest port city, have roots outside the Netherlands. In 2009, as a first in the Netherlands, and for any major European city, a foreign-born practicing Muslim became the mayor there. It is the shape of things to come. As the 2011 British census confirmed, the share of those identifying themselves as "white British" has dropped below 50 percent in London.
These changes confirm rather than contradict age-old trends. The other "native-Dutch" half of Rotterdam itself is largely the result of an influx of Brabanders in the 19th century, when the booming port attracted internal migrants from that rural part of the Netherlands (Brabant). So yesterday's migratory upheaval -- damn these swarms of Brabanders! -- is today's sepia-tinted nostalgia: Remember when Rotterdam was all Brabander? The past that some long for was itself in flux, and uncomfortably "modern." As stated in historian Peter Ackroyd's seminal biography of Britain's capital, Londoners in the past were known for their darker than Anglo-Saxon complexion, due to historical admixtures of Mediterranean, Semitic, and even more exotic blood. Meanwhile, that same British census reports that Polish is now England's second language.
Before 1989, Poland and Britain were on either side of what seemed an almost impermeable continental divide, both ideological and physical. Tucked away behind that Iron Curtain, Poland might as well have been on the moon. The Polish community in Britain then was tiny enough to be exotic and was so old that it was nearing extinction: Most were Free Poles stranded after World War II, unwilling to return to a homeland that had turned communist.