Introduction
At the European Council in Gothenburg (June 2001) the European Union adopted a common strategy for sustainable development as an integral part of the EU strategy for transition to a knowledge-based economy. Information and communication technologies (ICTs), such as computers, mobile phones and microchips, play a key role in the change towards this knowledge-based economy.

There are many single case studies on the impact of ICTs on isolated aspects of sustainability, but no coherent research on the full range of impacts has to date been carried out. The ‘Institute for Prospective Technological Studies of the European Commission’s Joint Research Centre’ commissioned the project ‘The future impact of ICT on environmental sustainability’ to explore qualitatively and to assess quantitatively the way that ICTs can influence environmental sustainability.

To define environmental sustainability, the project took seven indicators as a reference:

• Greenhouse gas emissions,
• Energy intensity of the economy,
• Transport intensity of the economy,
• Modal split of transport,
• Share of renewables in electricity consumption,
• Urban air quality,
• Municipal waste collected but not recycled.

The geographical coverage of the project is the member states of European Union (EU 15) plus accession countries (AC 10). The time horizon is 2020.

Methodology
The project adopted a five step methodology. In the first step a set of environmental indicators was chosen and the conomic sectors and ICT applications with the highest impact on these indicators were identified for further analysis.

The second step was to build up data as a basis for the project through an extensive literature review of the environmental impacts of selected ICT applications. Three kinds of impact were considered:

• The impacts and opportunities created by the physical existence of ICTs and the processes involved (first order effects);
• The impacts and opportunities created by the ongoing use and application of ICTs (second order effects);
• The impacts and opportunities created by the aggregated effects of large numbers of people using ICTs over the medium to long term (third order effects).

Thirdly, three consistent scenarios were developed, by choosing highly unpredictable factors likely to influence the development and use of ICTs in the future. The Table 1 shows the combination of uncertain factors in the following three scenarios:

• Technocracy: Government and business collude to produce high speed, growth-focused technology development.
• Government first: Heavy-handed government steers technology development to favour social outcomes, while business competes to exploit a slowing market.
• Stakeholders democracy: A positive environment for sustainable development, with all eyes on what ICT can deliver, but outcomes are not always straightforward.

In the fourth step a simulation model was built to quantify the future impact of ICTs on the environmental indicators for the three mentioned scenarios. The final step was to review the project results in setting them into the current EU policy context.

This led to a range of detailed policy recommendations, which were then validated by a panel of experts.

Results
It is possible to estimate the isolated effects of ICTs on different indicators. However, the most relevant information is not the direct impact of ICTs on one indicator, but the whole picture, including the evolution of all the indicators in relation to the development of ICTs.

The following figure presents the development of environmental indicators by 2020. These figures are percentage increase/decrease from the base year 2000. A negative value indicates that the indicator level would be higher without ICT, a positive value indicates that ICTs contribute to growth of the indicator. The length of the bars indicates the uncertainty of the findings, as a result of both future scenario variation and data uncertainty. There are two bars per indicator: the upper (dark blue) bar shows the results for projected ICT development, the lower (light grey) bar shows the results for the so-called ‘ICT freeze’ simulations (i.e., ICT applications remain at the same level as in 2000). The impacts shown are aggregated values of all ICT applications considered in all scenarios simulated.