Till the end of 2100 growth of population will stop at at around 11 billion

Michio Kaku : theoretical physicist
Given all these factors, the UN has continually revised its figures about future population growth. Estimates still vary, but the world population may hit 9 billion by 2040. Although the population will continue to increase, the rate of growth will eventually slow down and level off. Optimistically, it may even stabilize at around 11 billion by 2100.

"Physics of the Future"