How might a decreased youth and working age population affect our ability to deal with an international or domestic crisis? Some countries around the world are starting to worry about this question.  It is largely the youth and working age population that provides the manpower to deal with major national crises, if not necessarily the wisdom. 
One South East Asian news source this week questioned Singapore’s ability to be ‘resilient’ in the face of crisis, given its ageing population, low total fertility rates and the decreasing growth of what remains a large foreign population.  Examples of historical incidents include the discovery of the Jemaah Islamiyah plot to bomb several key areas in Singapore in December 2001 or the Severe Acute Respiratory Syndrome (Sars) outbreak in 2003.  The latest Singapore Population in Brief (PIB) 2014 report issued by the National Population and Talent Division reports that currently there are 5.2 citizens in the working age band of 20-64 years for each citizen aged 65 years and above.  In 2004 there were 7.6, in 1990 there were 10.4, and in 1970 there were 13.5 - a clear decline in the working age population over time.
The Business Insider Australia also published an article yesterday questioning whether Japan would have the ability to mount an effective military deterrence in the coming decades, given the country’s significant population decline. Currently, the Japanese self-defence forces are thought to be one of the top ten most effective fighting forces in the world.  They can only be used defensively or in international humanitarian missions.  However, the population will contract by almost a third within the next 90 years, almost irreversibly limiting the nation’s military capabilities.  According to Aki Peritz, a former CIA analyst, demographic decline will lead to greater competition for access to Japanese youth in every facet of society.
Though a lack of ‘manpower’ may be a problem, it is to be remembered that collectively older people have a lot of skills and wisdom.  A strong knowledge of history and what has come before is not to be under-estimated.  The Singaporean article comments:

Those above the age of 65, while no longer youthful, possess stores of experience in diverse areas which can be tapped on where there is need. As the World Health Organisation (WHO) noted in a report titled Older persons in emergencies: An active ageing perspective, “their years of experience can make them models of personal resilience and sources of inspiration and practical knowledge”. As such, instead of being regarded as a group that requires assistance, those with specific experience or expertise should be maintained and called upon should the need arise.

…Closer to home, in the aftermath of the Sars outbreak former Prime Minister Goh Chok Tong made it a point to thank not only Singaporean but also foreign healthcare workers for staying on in the country, noting that “they could have simply returned home. But they stayed on and stood shoulder-to-shoulder with us".
Thus, a whole of society – and even a whole of world – approach may become increasingly necessary to deal with future crises in one or more countries, as will be the appreciation of the wisdom and skills older people have to offer.  We should also be mindful of the crucial role well-brought-up childrens' futures play in the future well-being of society and the world.  Those who bring them up do a crucial service to society.