Definition of infrastructure
In our context, we are applying the following definition of infrastructure:

Physical infrastructure such as buildings, structures, networks for communication and transport, plants and networks for water supply and wastewater treatment, plants for solid waste treatment and energy production, and networks for energy distribution.

In addition to the physical infrastructure, there is a need for a geometrically based infrastructure for positioning, accessibility and management. Infrastructure thereby comprises the built environment and basic geographical information.

Values of infrastructure
The activities within the building and construction sector represent great values and challenges to a society regarding sustainable development. A well developed and maintained infrastructure is a fundamental need for a modern society, and its value and importance can be expressed in different ways. In Norway, the physical infrastructure is estimated to have a value of about 70 % of the national physical capital, and the necessary replacement costs are estimated to at least NOK 4750 billion (EUR 600 billion). In Europe (the EU15 countries), the building and construction industry had about 14 million employees and a turnover of about EUR 1000 billion in 2004. Globally, more than 111 million people are working within the sector. The activities contribute to about 10 % of the gross domestic product, and in 2002, global annual investments were estimated to a value of about USD 3000 billion.

At the global level, the built environment in each country is estimated to account for about

• 25-40 % of the energy consumption
• 30-40 % of the material resource consumption
• 30-40 % of the waste production
• 30-40 % of the greenhouse gas release

For many of the industrialised countries, the figures are mainly at the upper end of the intervals given above.

Infrastructure and the environment
There is a mutual relationship between the physical infrastructure and the environment. The extensive activities within the building and construction sector throughout the entire lifetime of the infrastructure (construction, management, deconstruction and recycling) have a great influence on the environment due to the use of resources (materials, energy, water, land) and various environmental loads. On the other hand, the influence of the environment and the climate exposure on the infrastructure will be of importance regarding location, design, material use, management and service life of the infrastructure.

Effects of infrastructure on the environment and sustainable development

Due to the extensive activities and values of the building and construction sector as indicated above, it will have a most important impact on the environment and sustainable development of a society. In the Agenda 21 for sustainable construction from CIB (International Council for Research and Innovation in Building and Construction), it is stated that

“This sector of society is of such vital innate importance that most other industrial areas of the world society simply fade in comparison. The construction industry and the built environment must be counted as two of the key areas if we are to attain a sustainable development in our societies.”

Effects of environment and climate on the infrastructure
Regarding the environmental stresses on the infrastructure, this item has gained a strong focus over the last years. Globally, there are today very much discussions and concern regarding the consequences of the climate change going on, and this will have a great impact on the various types of infrastructure in the future. This will be both for the existing infrastructure regarding maintenance and improvement, as well as for the new infrastructure regarding positioning, design and material use.