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The global population is likely to grow to between 8.3 and 10.4 billion by 2045, largely because of increasing life-expectancy, declining levels of child mortality and continuing high birth rates in many developing countries. Growth is not likely to be evenly distributed and will probably be slower in developed countries. Some, including Japan and a number of European countries, are likely to experience a decline in population.
In developing countries, rapid population increase and urbanisation will probably challenge stability. Age and gender imbalances may exacerbate existing political and social tensions while a growing youth population, especially in the Middle East, Central Asia and sub-Saharan Africa, could provide a reservoir of disaffected young people.
Conversely, if harnessed, they could provide a boost to their economies. Migration is likely to increase, with people moving within, and outside, their country of origin to seek work or to escape the effects of climate change.