In recent years there has been a growing concern over thresholds or tipping points in nature. For example, scientists worry about when the shrinking population of an endangered species will fall to a point from which it cannot recover. Marine biologists are concerned about the point where overfishing will trigger the collapse of a fishery.

We know there were social tipping points in earlier civilizations, points at which they were overwhelmed by the forces threatening them. For instance, at some point the irrigation-related salt buildup in their soil overwhelmed the capacity of the Sumerians to deal with it. With the Mayans, there came a time when the effects of cutting too many trees and the associated loss of topsoil were simply more than they could manage.

The social tipping points that lead to decline and collapse when societies are overwhelmed by a single threat or by simultaneous multiple threats are not always easily anticipated. As a general matter, more economically advanced countries can deal with new threats more effectively than developing countries can. For example, while governments of industrial countries have been able to hold HIV infection rates among adults under 1 percent, many developing-country governments have failed to do so and are now struggling with much higher infection rates. This is most evident in some southern African countries, where up to 20 percent or more of adults are infected.

A similar situation exists with population growth. While populations in nearly all industrial countries except the United States have stopped growing, rapid growth continues in nearly all the countries of Africa, the Middle East, and the Indian subcontinent. Nearly all of the 80 million people being added to world population each year are born in countries where natural support systems are already deteriorating in the face of excessive population pressure, in the countries least able to support them. In these countries, the risk of state failure is growing.

Some issues seem to exceed even the management skills of the more advanced countries, however. When countries first detected falling underground water tables, it was logical to expect that governments in affected countries would quickly raise water use efficiency and stabilize population in order to stabilize aquifers. Unfortunately, not one country-industrial or developing-has done so. Two failing states where overpumping water and security-threatening water shortages loom large are Pakistan and Yemen.

Although the need to cut carbon emissions has been evident for some time, not one country has succeeded in becoming carbon-neutral. Thus far this has proved too difficult politically for even the most technologically advanced societies. Could rising carbon dioxide levels in the atmosphere prove to be as unmanageable for our early twenty-first century civilization as rising salt levels in the soil were for the Sumerians in 4000 BC?

Another potentially severe stress on governments is the coming decline in oil production. Although world oil production has exceeded new oil discoveries by a wide margin for more than 20 years, only Sweden and Iceland actually have anything that remotely resembles a plan to effectively cope with a shrinking supply of oil.