Under what circumstances does labor productivity grow?

Say that the average worker in the U.S. economy is eight times as productive as an average worker in Mexico. If the productivity of U.S. workers grows at 2 for 25 years and the productivity of Mexicos workers grows at 6 for 25 years, which country will have higher worker productivity at that point?

Is it possible to protect workers from losing their jobs without distorting the labor market?