But that's not enough: To maintain energy security, one needs a supply system that provides a buffer against shocks. It needs large, flexible markets. And it's important to acknowledge the fact that the entire energy supply chain needs to be protected.

In a world of increasing interdependence, energy security will depend much on how countries manage their relations with one another. That is why energy security will be one of the main challenges of foreign policy in the years ahead. Oil and gas have always been political commodities.

First, we have to find a common vocabulary for energy security. This notion has a radically different meaning for different people. For Americans it is a geopolitical question. For the Europeans right now it is very much focused on the dependence on imported natural gas.

Clearly, the Chinese need the resources, but I don't think they want to clash with the industrial world which happens to be the market for their goods.

The world has produced about 1 trillion barrels of oil since the start of the industry in the nineteenth century. Currently, it is thought that there are at least 5 trillion barrels of petroleum resources, of which 1.4 trillion is sufficiently developed and technically and economically accessible.

People always underestimate the impact of technology. To give you an example: In the 1970s the frontier for offshore development was 200 meters, today it is 4,000 meters.

According to one study by the United States Geological survey, 86 percent of oil reserves in the United States are the result not of what is estimated at the time of discovery but of the revisions and additions that come with further development.