The geopolitical and financial risks facing the global economy are well-known. Hot wars and currency meltdowns garner headlines around the world.

But few even hear, much less discuss, four ticking global time-bombs:

1. The demographic time-bomb.

2. The public health time-bomb.

3. The food/water/soil time-bomb.

4. The oil-export time-bomb.

Each is largely self-explanatory:

1. The demographic time-bomb: as the global economy melts down, the realization that the pensions and healthcare promised to hundreds of millions of elderly cannot be funded out of tax revenues will upend the social contract in countries rich and poor.

As the chart below depicts, as the population of elderly rise, so do the non-communicable lifestyle diseases of aging. The costs of treating these lifestyle diseases (metabolic syndrome, heart disease, high blood pressure, etc.) soar as the population and incidence of these diseases both rise.

Global Aging 2010: An Irreversible Truth:

This Standard & Poor’s study warns that “no other force is likely to shape the future of national economic health, public finances, and policymaking as the irreversible rate at which the world’s population is aging… The cost of caring for [the elderly] will profoundly affect growth prospects and dominate public finance policy debates worldwide.”

2. The public health time-bomb: 100 million diabetics and 500 million pre-diabetics in China, 80 million diabetics and hundreds of millions more pre-diabetics in India, and another 100 million diabetics in the developed world will overwhelm a global healthcare system that is already struggling to provide care for an aging population.

Diabetes Is a Major Public-Health Crisis in China

No Answers in Sight for India’s Diabetes Crisis

The Global Diabetes Epidemic (New York Times)

3. The food/water/soil time-bomb:the world’s success in feeding its exploding population of humans and their favored animals has generated a complacent confidence that we can always grow more food, even as the weather gets increasingly wonky and global supplies of fresh-water are strained to the breaking. Loss of soil and the depletion of mineral fertilizers are also global issues.