Who will pay for the elderly?

Who will pay for the elderly? This is a big question in Germany as it is in many countries. Here, the problem is becoming somewhat acute. Statistics show that by 2040 there will be about 29 pensioners for every 12 people working. Who will pay their pensions when the numbers are so skewed? They've recently increased the retirement age to 67 from 65. Will the retirement age be 75 or 80 in 2040? Will old people just have to work until they die? These are realistic scenarios but they aren't being discussed.

The birthrate is incredibly low and the only people really having kids are foreigners. The percentage of foreigners in the overall population is still quite low in Germany but will only steadily increase. Will this concomitantly increase nationalism (which is already on the rise, as evidenced in the increasing political power of far right parties)?