One assumption that many economists make is that economic growth will continue to be possible throughout the future because people will continue to develop new technology and increase productivity.

Some argue that economic growth will not always be possible.  Others say that economic growth is not even desirable, as it usually hurts the environment.

Human usage of raw materials has greatly increased since World War II.  The world population has grown from 2.5 billion to almost 6 billion, and the amount of consumption per person, especially in the developed countries, has increased greatly as well.

Rapid economic growth has also taken place during this time period.  This has come greatly from increased productivity, and through greater use of natural resources.

Some people say that eventually, growth will slow down or come to a halt because economies will no longer be able to exploit natural resources unlimitedly.  When natural resources run out or diminish, economies may not have the raw materials needed to maintain present growth rates.

The majority of economists agree that while there is no absolute limit on growth, exhaustion of natural resources could restrict future economic growth.

Of course, it is highly difficult to predict the future.  Decades ago, the current level of use of nonrenewable resources may have seemed impossible, and the growth achieved today might have seemed impossible then.

There is still good reason for concern though.  While new technology may find replacements for nonrenewable resources, such as nuclear fusion doing away with the need to use our exhaustible supply of fossil fuels, it is difficult to say if these technological developments will occur before we run out of exhaustible resources.