Unlike pure public goods such as the atmosphere, where one person's use does not reduce the amount available to others, people deplete these resources when they use them.

ECONOMIST: Economics focus

Government handouts enabling consumption without production deplete our resources.

FORBES: Why The Recession Recovery Remains Anemic

Yet demand for air travel, and energy generally, is rising quickly in China and other developing countries - something likely to push up prices for the rest of us in future, as the world's oil resources deplete.

BBC: The great London airport debate