A Strategic Environmental Assessment (SEA) is a “systematic process for evaluating the environmental consequences of proposed policy, plan or programme (PPP) initiatives in order to ensure they are fully included and appropriately addressed at the earliest stage of decision making on a par with economic and social considerations”. 

The SEA provides recommendations feeding back into the planning process to optimise its environmental impacts (minimising negative effects and enhancing positive ones). Compared with the better known Environmental Impact Assessment (EIA), SEA provides for impacts to be taken into consideration at an earlier stage, prior to the definition of PPP, and allows a better control over interactions or cumulative effects. However it is less precise as many of the details of specific actions and locations are possibly not defined. 

For SEA to be most efficient it should be integrated into the PPP preparation process, which should take into consideration its recommendations. The following stages can typically be distinguished for the SEA process:

SEA Screening

Screening refers to the decision to undertake an SEA. SEAs are necessary for all PPPs that, when implemented, are likely to produce significant negative impacts on the environment.

SEA Scoping

Scoping refers to the identification and clarification of issues to be addressed by the SEA. Scoping should take into consideration the concerns and value judgements of stakeholders, in order to ensure that these are addressed in the SEA Study.

SEA study

The SEA study is more elaborate and comprises several stages.
The environmental baseline provides information for a general understanding of the state of the environment and trends in order to be in a position to assess the potential environmental effects of a PPP. The SEA should then identify and assess the potential environmental impacts of implementing the different PPP alternatives under study, in order to propose measures to mitigate negative environmental impacts and optimise positive effects. The consistency analysis identifies any elements of the PPP that may be in conflict with or hinder the achievement of environmental policy objectives. The SEA should produce recommendations for the implementation of the preferred and improved alternative, as well as monitoring indicators . The results of the SEA should be presented in the form of a concise SEA report . 

Public participation

The involvement of stakeholders in the SEA process is a key success factor. Environmental impacts cannot be dissociated from their relationship to social, economic and cultural factors. Engaging stakeholders in an SEA is important in order to adequately integrate their knowledge and concerns in making an adequate assessment of impact significance and acceptability of proposed actions and mitigation measures.
In the context of EC Development Co-operation the SEAs considered can be EC-driven, Government-driven, or prepared by other donors.

Although the consequences of General Budget Support (GBS) or Sector Policy Support Programmes (SPSP) on the environment are less direct and less immediately visible than the environmental impacts of an individual project, their influence can nevertheless be very significant.

A key tool to ensure that the policies, plans and programmes supported through GBS or SPSP (e.g. a National Development Strategy or a Sector Programme) contribute to sustainable development is the Strategic Environmental Assessment (SEA).

SEA in General

SEA is more of a generic term than a specific tool. This means that it can take different forms according to the specific needs: from a broad-brush and more qualitative approach for policy analysis, to a more detailed and quantitative approach for the analysis of specific programmes of projects; from a sustainability focus to a focus on the environmental dimension.
We could say that the ideal SEA is fully mainstreamed into the policy- plan- or programme-making process, and fully owned by the partner government. As SEA is still a recent tool, ideal SEAs are not always possible. In any case ownership should be encouraged and opportunities sought to co-ordinate SEAs with other donors.

SEA for SPSP

SEA determines whether the Sector Programme is consistent with the country's and EC's environmental policy objectives, and if the environmental impacts of Sector Programme implementation are likely to be significant. On the basis of this analysis it provides feedback to the Government to enhance the environmental dimension of the Sector Programme, and also enables improved integration of the environment into SPSP formulation.
In the context of EC development co-operation SEA can take the form of an EC-driven process to provide an input into the formulation of the SPSP. Only Sector Programmes with potential significant impacts on the environment when implemented will require an SEA, as determined through an SEA Screening process.

Strategic Environmental Assessment (SEA): Draft Terms of Reference

SEA in the EU
 Directive 2001/42/EC of the European Parliament and of the Council on the Assessment of the effects of certain plans and programmes on the environment
 EC SEA Directive - Legal context
 Environmental Assessment, EC-DG Environment
 Implementation of the EC SEA Directive: guidelines
 UNECE Protocol on Strategic Environmental Assessment (Kiev, 2003)