Depletion is the declining availability of natural resources. Wars for resources are both indicators and consequences of depletion. We are currently seeing such conflicts every month, and on every continent. Depletion demands that nations nationalize natural resource wealth. Depletion also demands that countries with precious mineral and energy resources acquire advanced weapons to defend those resources, or make strategic deals with nations that do have weapons. With treacherous circular logic, war requires nations to try to acquire strategic commodites at virtually any cost, to enable its military.
All the world's gigantic "elephant" oil fields are now in decline. This is depletion! Did anyone notice that Saudi Arabia admitted that their major legacy fields are now declining by 8% annually? This was reported by Platts news, and didn't stay live for long, but ASPO picked it up. Replacing enormous oil fields with smaller ones, at huge capital investment, will neither bring down the price of oil, nor increase supply. The largest copper mines are slowly becoming less and less productive. Depletion! Replacing big mines with smaller ones, at huge capital investment, will not bring down copper prices. The world will shortly face peak oil, peak copper, peak you-name-it. Note that we don't have to "run out" of any given commodity for it to become far more expensive, just for some mines or wells to become too expensive to operate because of declining yields, higher energy costs, and higher capital costs. If the problem is a production "bottleneck", then that is a result of depletion.
Wars and nationalization of resources will remove large sources of energy and mineral production off the open markets. This will mean that far more oil will change hands than is sold on the futures markets. Oil will be sold directly from one state oil company to another, at secret prices. Nationalization is an unstoppable trend. Venezula moved only last week to nationalize "inactive" mines. Economists and investment analysts like to suggest that if nations with oil wealth would simply let private firms come in and invest massive capital then production would rise and we would not have a peak oil problem. Whether this is true or not, it does not benefit the oil producing nation. Protecting a strategically important resource, like oil, is far more important than getting the best price and highest production for that resource.
Even the United States will be forced to nationalize its remaining mineral and energy resources someday, if only to keep them out of the hands of its creditors.
Just as every nation must now attempt to create a secure energy supply, it is just as important to deny, or limit, energy supplies to strategic rivals. A nation that must use all its available energy just to maintain its own economy is a nation that is unlikely to go to war. Economists need to start admitting that these things are not anomalies, and that depletion exists. It is the trend. It is formenting nationalization and war.