Environmental vs. sustainability indicators
The original intention of SEA was to give additional consideration to the biophysical/ environmental impacts of strategic actions. However it is often difficult to fully distinguish environmental from social impacts: for instance landscape and noise are typically seen as 'environmental' but are heavily influenced by how people perceive them.
Most, possibly all, SEA systems consider at least some socio-economic aspects. For instance, the European SEA Directive refers to
"biodiversity, population, human health, fauna, flora, soil, water, air, climatic factors, material assets, cultural heritage including architectural and archaeological heritage, landscape and the interrelationship between the above factors"
and the UNECE SEA Protocol refers to:
"human health, flora, fauna, biodiversity, soil, climate, air, water, landscape, natural sites, material assets, cultural heritage and the interaction among these factors".
The factors in italics show that even legislation that specifically refers to strategic "environmental" assessment often has blurred boundaries that also include social and economic effects.
Focusing solely on environmental issues allows the environment to receive the prominence that was the original aim of SEA. However, also considering social and economic issues allows trade-offs between different types of issues to be made more transparent, for instance why a strategic action may propose new houses (on overriding social grounds) despite the fact that they will have negative impacts on land use, ecology etc. Consideration of social and economic as well as environmental issues could also be perceived by planners as being more well-rounded and realistic.
Separation or integration?
Traditionally, it was assumed that the separate economic, social and environmental indicators or targets must be "balanced": that one can only progress at the detriment of another. In SEA terms, a small environmental cost could be counterbalanced by a large social or economic gain.
Since the Brundtland Report (WCED 1987), however, much more emphasis has been put on "integrating" the different types of objectives. Sustainable development is often portrayed as three intersecting circles - environment, society, economy - with the central part representing sustainability. In SEA terms, then, a sustainable strategic action would be one that performs positively for all three types of indicators.Levett, instead, (1997) argues for a new definition:
"Most treatises on sustainability are decorated with three intersecting circles representing the intersection of social, environmental and economic goals. But actually there is no economy - or society - without environment. A thought experiment: would the future look rosier if we had (a) wonderful community involvement, equitable participation and an unstoppable runaway greenhouse effect, or (b) despotism, oppression, and unlimited time free from ecological pressure to resist them and civilise ourselves (a one-sentence summary of human history up to 1800?).
Furthermore 'the economy' is not an end in itself or a force of nature. It's a social construct -- it only works as it does because human societies have created the institutions, and inculcated the assumptions, expectations and behaviours which make it so. The only reason for keeping it thus and not otherwise is if we think it will be good at meeting our needs.
So the picture is really three concentric circles: economy within society within environment. This says sustainability is about ensuring that human society lives within the environment's limits -- and that the economy meets society's needs."
The animation below illustrates Levett's argument further.
In SEA terms, 'integration' would involve the use of different types of indicators: indicators that reflect this hierarchy and that internalise the integration. The UK Local Government Management Board's indicators are an example of this: it would be difficult to categorise any of the indicators as being purely environmental, social or economic.