by Robert Greenhill – Managing Director, Chief Business Officer, World Economic Forum. 

Robert Greenhill "Demography is destiny" is an old phrase and may seem an exaggeration. However, there is no doubt that two major demographic trends–an ageing population in developed and emerging economies, and high population growth in parts of the developing world will have an enormous impact on our prosperity in the future.

An ageing population in North America, Western Europe and most of the BRICS will cause major challenges to already stressed government budgets and healthcare programmes. Shifting government programmes and social attitudes to support an active ageing population will be key to prosperity in the future of these economies. The challenges are enormous as are the opportunities if the skills and wisdom of the "silver generation" can be fully harnessed.

The challenge of population growth is perhaps even greater. Although many view this as a past problem, the reality is quite different. It took only 12 years for the world's population to grow by 1 billion to an estimated 7 billion people by next month. The UN Population Division estimated in 2008 in its medium scenario that global population would stabilize at 9 billion in 2050. Recently, it changed its opinion; it now sees global population increasing to 10 billion by 2100.

UN Projections of World Population Under Three Fertility Assumptions

More importantly, this future population growth to 10 billion is only one scenario in a large range. Under low-growth scenarios, population could stabilize by 2040 at around 8 billion. Under high-growth scenarios, it could grow to as much as 12 billion by 2060 and 16 billion by 2100 (please see attached graph).

Clearly, our collective efforts to address poverty, food security, climate change and other resource challenges are hugely affected by whether the global population peaks at 8, 10, 12 or 16 billion. As one commentator said: "Anything below the 10-billion line is opportunity; everything above is catastrophe."

Rapidly Rising Share of Older People in World Population

Perhaps the greatest challenge is that 90% of this growth will be concentrated in the poorest areas of the poorest countries. Those populations currently facing poverty and hunger will grow the fastest. Somalia is expected to triple its population by 2050, Niger to quadruple. Fourteen countries with 450 million people have very high fertility with present water or food shortages. Unaddressed, these dynamics could cause many of these countries to collapse.

There is a great opportunity in addressing these population dynamics positively. A rapid decline in population size could assist fragile countries to accelerate their development and secure their future.

Evidence shows that the way to accomplish this is not through "population control" but through "family empowerment": educating girls, ensuring that women have the right to choose whom and when they marry, assisting families to reduce child mortality, providing access to affordable family planning and providing a supportive social context for those who wish to have fewer children. The positive empowerment of women and families has driven the most successful reductions in population growth around the world.

The World Economic Forum Global Agenda Councils on Ageing and Population Growth have been leading the thinking on these critical issues. Council members participated this past week as special speakers in the opening plenary of the World Ageing and Generations Congress.