Population and the future

After examining how world population reached the current total of 7.2 billion, this article uses 2012 population projections to show how the numbers of people, their distribution, fertility and mortality might change over the next 90 years, and the consequent changes in world age structures. A brief discussion of global migration patterns, particularly rural to urban and the resultant growth in the urban population, leads into the final section which considers demographic pressures and global challenges in the 21st century as a result of growing numbers, migration and changing population structures.