Here's One Way to Double the World's $80 Trillion Economy: Scrap Migration Restrictions

Eliminating cross-border barriers could lift global GDP by as much as 147 percent

Global growth could use a little more juice these days. The answer could be easier than we think: We need to get moving.

While a freer flow of goods alone can boost global gross domestic product by a modest amount, loosening of restrictions to international migration could lift growth worldwide by 67 percent to 147.3 percent, according to economists' estimates cited in research by Mark Wynne, vice president of the Federal Reserve Bank of Dallas. (Global GDP will probably be $81.5 trillion this year, International Monetary Fund estimates show.)

International migration is the "last frontier of globalization" while also appearing to show the least progress in recent decades, writes Wynne. While voluntary world migration showed progress between 1990 and 2010, it's been a slow climb in the post-World War II era, and nowhere near as simple as the passport-less world of a century ago, he writes.

Source: Federal Reserve Bank of Dallas

The movement brands winners on both sides, with recipient countries building their markets (including through human labor and consumer spending), and originating countries benefiting from money sent back to the home front. Those remittances can add up to 5 percent or more of a poor country's GDP, according to the Dallas Fed.

The U.S. is still winning in overall stock of international migrants, with more than three times as many foreign-born residents than next-closest Russia. The group was more than40 million strong in 2012, according to Census Bureau data.

Accounting for population size, however, there are clearer winners. Of the top 10 countries with the most international migrants, Saudi Arabia boasts the highest share of international migrants, with 26.7 percent. The U.S. is about half that slice of the pie, at 13.8 percent.

And yet too-tight immigration policies could be an albatross for the American economy in decades to come, especially via slower gains in innovation, said Savita Subramanian, head of U.S. equity and quantitative strategy at Bank of America Merrill Lynch. 

"It's still a risk — if we do lose the ability to hire from abroad and attract talent from overseas, that could be a knock" for research and development spending and the resulting boost to our standard of living, said Subramanian.