Städer och planetära gränser : En utvärdering av Stockholms ochNorra Djurgårdsstadens påverkan påde planetära processerna

Sammanfattning: The concept of planetary boundaries was introduced in the year 2009 by a group ofresearchers led by Johan Rockström and Will Steffen. The group presented a draft of thelimits of the planet regarding nine Earth System processes concerning climate change, oceanacidification, stratospheric ozone depletion, atmospheric aerosol loading, interference with Pand N cycles, global freshwater use, land-system change, rate of biodiversity loss andchemical pollution. The starting point for the study presented in this report was that asustainable development only can be achieved if humankind stays within the boundaries. It istherefore, based on the ongoing urbanization, relevant to evaluate how cities affect the EarthSystem processes. The aim of the study was to investigate if Stockholm Royal Seaport (NorraDjurgårdsstaden), a district in the northeast of Stockholm with a clear environmental profile,affects the Earth System processes less than Stockholm in general does. If so, the district hasmore favorable conditions for a sustainable development. In order to do this, an investigation by Miljöförvaltningen (2012) in Stockholm was used.It presents the environmental impact of Stockholm using “influencing factors”(påverkansfaktorer). By comparing the structure of this investigation, including the targetareas the influencing factors belong to, with how Rockström et al. (2009) describes theprocesses and the boundaries, it was possible to connect influencing factors to each process.For example, the influencing factors shrinking area and barriers, overgrowth and monocultureas well as chemical influence was linked to the loss of biodiversity, the influencing factors Pand N to the P and N cycles, CFC and HCFC to stratospheric ozone depletion, greenhousegases to both climate change and ocean acidification plus a lot of different substances tochemical pollution and atmospheric aerosol loading. However, for the process regardingglobal freshwater use, only one influencing factor could be connected and for land-systemchange, no one at all. This indicates that Stockholm affects these two processes less than theothers, but the suitability of using the locally adapted influencing factors as indicators for theimpact on the global Earth System processes can be questioned. That something is notperceived as an environmental problem in Stockholm does not necessarily mean that the citydoes not contribute to it and Stockholm’s relation to these processes should be investigatedfurther. By the help of the sources for each influencing factor, the influence of Stockholm RoyalSeaport on the Earth System processes was than compared and evaluated with Stockholm’sditto. The environmental program for the district and two environmental impact assessmentswas used as representatives for Stockholm Royal Seaport. 17 out of 24 influencing factorswere judged to be better for Stockholm Royal Seaport than for Stockholm in general, for sixno judgment could be made and for one no difference could be identified. In total, this meansthat Stockholm Royal Seaport affects all Earth System processes, except global freshwateruse and land-system change, less than Stockholm. This is obviously positive bearing in mindthe environmental profile of the district and it does also mean that the district has betterconditions for sustainable development than Stockholm. The implementation of a traffic hierarchy In Stockholm Royal Seaport, with pedestriantraffic, bicycling and public transport prioritized has positive effects for several of the EarthSystem processes. The use of green spaces is also positive. Future studies may investigate thedistrict after being put into service and should feel free to include how consumption isrelevant. To evaluate a district which is still being planned is also needed, but the reality tendsto differ from the planning. Questions were also raised about if it is possible to separate onepart of a city from another, since some properties is split between several districts. Thedevelopment of the concept of planetary boundaries should of course be followed and mostpreferably be related to the social and economic aspect of sustainable development.