The European Environment Agency defines an indicator as "a representative observed value of a phenomenon to be studied".
What is an environmental indicator?
Indicators quantify information by combining multiple and different data. The resulting information is thus synthesized. Indicators therefore simplify information that can help in revealing complex phenomena.
Indicators focus on certain aspects of a problem, that are considered to be essential and for which data is available.
There are many different environmental indicators.
They are usually classified according to a model called "DPSIR", D for Driving Forces, P for Pressures, S for State, I for Impacts and R for Responses.
This model is the one used by the European Environment Agency.
The DPSIR model presents an analysis of the systems: social and economic development put pressures on the environment and due to this, the state of the environment changes. This has an impact on, for example, the human health, ecosystems and materials, which may result in a response from the society that has effects on the driving forces, pressures, state of the environment or directly impacts, through adjustments or remedial actions.
Key: DPSIR model of the European Environment Agency (source)
What are the indicators used for?
Growing concern vis-à-vis environmental issues has fuelled the need for developing understandable and reliable environmental information. This has also led to efforts for measuring the state of the environment in many countries and international organisations such as the United Nations, in order to analyse and report scientific information on the subject.
The purpose of an environmental indicator is to communicate information about the environment and the human activities that affect it, in order to highlight emerging problems and draw attention to the effectiveness of the existing policies.
What are the federal indicators?
Since the Federal Authority does not report on the state of the environment, most of the indicators are of the driving force or response types.
In federal notes on environmental indicators, one can find several types of federal indicators, such as nuclear waste management, CO2 emissions from cars, quantities of pesticides and biocides put up for sale in Belgium, etc.