Approximately half of American jobs could be replaced by automation in the coming years, and roughly one in four are at risk of being lost to foreign competition, according to a study recently published by Ball State University.

Researchers combined recent studies on employment trends in their paper, "How Vulnerable are American Communities to Automation, Trade, and Urbanization?" and concluded the factors “contributing to this period of economic, social, and political unease are likely to continue in the coming decades."

"We do not wish to be alarmist," the researchers said. "Both trade- and automation-related economic growth are hallmarks of a vibrant economy. The findings of direct and indirect impacts of displacement are not homogeneous across populations. The negative long-term impacts of displacement have been found to be worse for low-skilled, less-educated workers, who are likely to work in more vulnerable jobs."

Employees at risk of losing their jobs to automation are low-skilled workers with lower wages, while virtually all labor markets are susceptible to job losses because of foreign competition.

The U.S. economy has already lost about 71,000 retail jobs to machines since the beginning of this year, according to a report in The Wall Street Journal.