Solving for the divergence between the worker-poor economies of Western Europe and the worker-rich nations of Africa would seem to be easy: Just encourage migration from the job-poor to the job-rich nations, right?

That solution has worked for the U.S., whose aging population has been offset by an influx of workers from Central and South America. According to the Chicago Council on Global Affairs, cities in the Midwest experienced a 20 percent decline in the number of native-born residents ages 35 to 44 in just the first decade of the 21st century. By welcoming foreign workers, Chicago has cut by about 25 percent the rate by which its working population is shrinking.

The same solution will not work in Europe, at least according to the Freedom Party in Austria, the National Front in France, and other rising right-wing parties, at whose core is a deep hostility toward immigrants and immigration.

Natalia Banulescu-Bogdan, an assistant director at the Migration Policy Institute in Washington, D.C., says such opposition is often a function of immigration that is—or just seems to be—out of control. “The influx of new talent and skills can be a very dynamic force,” she says. “We’ve seen a lot of cities really benefit from this influx of human capital, becoming hubs of innovation. But the rapid changes that people are seeing at a community level can sometimes cause a fraying of the social fabric.”

The countries that open their doors the widest don’t always have the most social problems, though. Spain has absorbed a high number of African immigrants in recent years without suffering political backlash.

When planning and preparing for the social conflicts that accompany immigration, it can be the pace of the change that matters most, Banulescu-Bogdan says.

“If you’re looking at the Netherlands, for example, the foreign-born population has increased only incrementally in the past decade, yet they have a very vibrant anti-Muslim political party.” The reason for that, she says, is that the influx of immigrants arrived in one big wave rather than gradually.

“When changes happen very quickly, then that’s when services and infrastructure at the community level can become overburdened,” she says, “and that’s when you really notice that changes are happening and the government seems not to be in control of them.”

Preparing for increased burdens to infrastructure is important because that is where indications of rapid change are most visible and tangible—a bus that’s too full or a school with too few teachers.

But there is the intangible to worry about as well. How does a community preserve or adapt its sense of identity as new populations subtly and not so subtly alter its character and cultural norms?

Banulescu-Bogdan says the cities that have dealt with the problem best have managed to embrace the concept of change as part of their identity. “Cities like London, Rotterdam, and Barcelona have put a great deal of effort into signaling, ‘We’re a welcoming city. We welcome diversity.’”

The prospect of greater economic output and an expanding tax base gives governments powerful incentives to take this approach, she says, but success will depend on their societies’ making good on the invitation.

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