To begin industrial processes, people withdraw natural resources from the environment.

The industrial system transforms these natural resources into nearly all of the products and services that we use . . .

• the food we eat
• the clothes we wear
• the cars we drive
• the electricity we use to light out homes and power our computers

Virtually all of the natural resources that support this activity ultimately return to the environment, often in an altered form.

This flow of materials from nature to the economy and back -- the materials cycle -- is fundamental to industrial economies.

As human populations increase and industrial activity expands, pressures on the environment are intensifying.

• Resource consumption continues to rise and pollution and ecosystem degradation continue to increase.

• In developing countries, resource consumption and waste generation are rising broadly in line with economic growth.

• In thinking about more rational ways of meeting demands for key natural resources in the future, it is necessary to think about the entire use cycle, from production to final consumption and disposal.

There is real doubt as to whether the earth has the capacity to support continuously escalating levels of resource extraction and disposal.

For the past five years, WRI and research partners in Europe and Japan have been working to develop databases and indicators that document the flow of materials through industrial economies.

Material flows analyses track the physical flows of natural resources through extraction, production, fabrication, use and recycling, and final disposal, accounting for losses along the way.

The goal of our materials flow studies is to develop new thinking, new metrics, and new management tools, which will help bring about the transition to more efficient and less environmentally-harmful patterns of material use in modern societies.

Why measure material flows? The case for a systematic framework of physical accounts. Just as economic flows are measured in dollars, tons of material provide a natural metric for gauging the physical flows inherent in industrial activity – the flows of natural resources, goods, pollutants, and wastes engendered by an industrial economy.