by those meat-eating animals is estimated to enter their predator animals. Thus, energy is transferred to higher-level creatures (from pray to predator). The higher the energy that is transferred, the more energy is consumed. Therefore, the remaining energy becomes smaller and smaller as it is transferred to higher-level creatures.

Thus, energy is consumed by various life at different levels, and heat generated as a result of their activities will be returned to the atmosphere. (Energy not consumed immediately is temporarily stored inside life or in the form of organic sediments, but it will eventually be released into the atmosphere, except for those organic compounds accumulated little by little underground such as petroleum and coal.) Then, heat in the atmosphere will be radiated into outer space. The amount of such heat is supposed to be equal to the incoming counterpart when the integrity of the ecosystem is maintained.

## Section 2: Crisis of Ecosystems

Development of science and technology that embodies the integration of people’s wisdom has provided human beings with a great fortune. Modern technology has made it possible for us to act decisively. People today receive great benefits from such activities: they take the form of artificial alteration of river flows for agricultural or flood-control purposes, deforestation, land reclamation, etc. However, today, people are sometimes unable to forecast the outcome of their activities due to unprecedented development of science and technology. We have acquired strong powers of advanced technologies, but any abuse of such high-level technology could possibly lead to an irrevocable alteration of ecosystems, including that of human beings.

The said scientific development has also brought about an increase in the world population. During the period between 1960 and 2000, the global population doubled from about 3 billion to about 6 billion. This means that we need twice as much ecosystem services, assuming that all other prerequisites remain the same as before.

In addition, in the latter half of the 20th century, the per capita demand for ecosystem services increased dramatically, especially in advanced countries due to their economic growth and people’s stronger desire to enjoy comfortable life.

There is a new analytical methodology named “Ecological Footprint” that attempts to measure human consumption of natural

## Column : Ecological Footprint

The Ecological Footprint (EF) is an index developed by the University of British Columbia to represent the level of human being’s dependence on the natural environment, in an easy-to-understand way. The Global Footprint Network defines the Ecological Footprint as “a resource management tool that measures how much land and water area a human population requires to produce the resources it consumes and to absorb its wastes under prevailing technology,” and makes a global assessment of the EF. The analysis of the EF includes the measurement of cropland required for the production of food, etc., grazing land required for the production of stock farm products, etc., fishing grounds required for the production of

Ecological Footprint by country

Note: Figures indicate the number of planet earths in terms of the ecological footprint of specific countries

Source: Compiled from the Living Planet Report 2006 (WWF) by the Ministry of the Environment

marine products, forests required for the production of timbers, forests required for the absorption of carbon dioxide.

According to the “Living Planet Report 2006,” published by the World Wildlife Fund for Nature (WWF), the Ecological Footprint (“demand”) exceeded the Earth’s biocapacity (“supply”) by about 25% as of 2003. If this state of demand over supply continues, ecological resources on the Earth will not be able to meet human needs in the end. Especially in many advanced countries such as the United States, EU nations and Japan, the EF shows overshooting. (CO $ _{2} $ emissions caused by the consumption of fossil fuels occupy a large part of the EF.) Japan’s EF as of 2003 was 2.5 times the global mean biocapacity (per capita), and the EF of EU nations (member nations as of 2006) and the United States were 2.7 times and 5.4 times respectively. This means that if the entire world adopts Japan’s, the EU’s or United States’ lifestyles, a world population would demand 2.5, 2.7 or 5.4 planet Earths respectively.