Sustainable Development - Changing Meangings

Conserving life-support systems
Ensuring renewable resources are sustainable
Keeping within the carrying capacity

from Caring for the Earth:

A sustainable society enables its members to achieve a high quality of life in ways that are ecologically sustainable. To measure progress toward a sustainable society, we need indicators of quality of life and of ecological sustainability.

Requirements of indicators

The concepts of quality of life and of ecological sustainability are broader than their measurement. By definition, indicators can measure only components of either. The search for reliable and efficient indicators of sustainability is just beginning. The indicators should be quantitative and some at least should be convertible to a monetary value so that they can be related to the national accounts. They should not be too difficult or expensive to measure. The following list of possible indicators is by no means comprehensive. Some do not meet these criteria.

Quality of life

The United Nations Development Programme has adopted two indices to measure human development or the quality of human life: a Human Development Index (HDI) and a Human Freedom Index (HFI).

HDI has three components:

Longevity, measured by life expectancy at birth. Long life is valued because it increases the opportunity for a person to pursue goals and develop abilities and is associated with good health and adequate nutrition.
Knowledge, or educational attainment, measured by adult literacy and mean years of schooling. This helps people to realize their potential and take advantage of opportunities.
Income, measured by per capita Gross Domestic Product, adjusted to account for national differences in purchasing power and the distorting effect of official exchange rates (real GDP), and adjusted further to reflect diminishing returns from income.

HFI is a modification of Charles Humana's World Human Rights Guide, which uses 40 indicators to measure freedom. A "one" is assigned to each right or freedom that is protected and a "zero" to each right or freedom that is violated.

Ecological sustainability

A society is ecologically sustainable when it:

conserves ecological life-support systems and biodiversity;
ensures that uses of renewable resources are sustainable and minimizes the depletion of nonrenewable resources;
keeps within the carrying capacity of supporting ecosystems.

Source: IUCN, UNEP, WWF, Caring For the Earth; A Strategy for Sustainable Living, Gland, Switzerland, 1991, p. 198.