Ecosystem Services in Stockholm - Challenges and Opportunities

Abstract

Ecosystem services (ES), the benefits humans receive from nature, increasingly come under pressure in Stockholm, one of the fastest growing capitals in Europe. To enhance the amount of eco-efficient area, Stockholm developed the Green Space Index (GSI). It is not known which areas in Stockholm might be particularly vulnerable in terms of ES availability, or whether the GSI objectively improves ES availability.

The aim of this thesis was threefold. Firstly, to provide an overview of the current distribution of ES in the city; secondly, to test for a potential correlation between ES availability and socio-economic opportunity; thirdly, to test for differences in ES availability between an area where the GSI had been implemented, and areas without the GSI. Specifically, the ES of stormwater retention, annual water retention, heat mitigation, and nature access were assessed.

For quantifying ES, the Urban InVEST models from the Natural Capital Project were used. Results from the models were combined to form a heatmap of ES. A correlation between socio-economic opportunity and the availability of ES was assessed with a Spearman correlation test on the neighbourhood deprivation index (NDI) and the ES. The NDI measures income, education, population receiving social benefits, and employment. Differences between the areas with and without GSI were tested for with t-tests. All statistical analyses were conducted in RStudio.

The analysis revealed that the ES in Stockholm are available less in the city centre and increase towards the outskirts. Economic opportunity in a district is negatively correlated with stormwater retention, annual water retention, and nature access – the higher the socio-economic opportunity, the less of these services is available.

Where the GSI had been implemented was significantly different from all the areas it was compared to. Due to different types of land use both water retention services are lower in the GSI area compared with the situation prior to redevelopment, the residential area, and one of the three other areas that had been redeveloped without the GSI. For heat mitigation, the GSI area performed worse than two of the redeveloped areas.

While the outskirts seem to be better provided with ES, this does not mean that the demands are met everywhere. Large parts of the construction in the coming decades are planned to take place in these less well-off areas, potentially threatening the natural elements providing ES and affecting populations that are less well equipped to make up for the loss of ES. The GSI can be a powerful tool to combat this. However, the research uncovered some shortcomings that should be addressed: striving for a high GSI score is not sufficient, measures with which the GSI is achieved must be suitable for the needs of the location. A process focussed on uncovering these needs first, or splitting up the GSI into several assessment categories, could aide in this.

Future research should continue assessing the GSI, either in a scenario analysis, or by monitoring. With these findings, the present thesis hopefully contributes to an improved understanding of ES in Stockholm.