The GAIA Conceptual Framework Environmental assessment address a broad range of diverse themes or topics. Issues are not, per se, directly measurable entities, but can rather be understood as a more or less loosely coupled set of indicators and their interpretation in a broader environmental and socio-economic and political context. Indicators , however, are representing measurable entities, which may be described on either cardinal or ordinal scales. Issues are controversial, subject to debate, and require interpretation. Indicators are linked to issues through subjective interpretation and complex evaluation.
Indicators illustrate issues.
Indicators are derived from environmental DATA by simple algorithms such as summation, averaging, interpolation, based on subjective agreements of experts or a well defined regulatory framework of environmental standards and agreements. The central concepts in GAIA are issues and their related indicators, illustrated by specific case studies. However, given the dynamic concept of sustainable development, many common indicators are inadequate. Methods for assessing interactions between different sectoral environmental, demographic, social and developmental parameters are not sufficiently developed or applied.