The Green Area Factor: Supporting Urban Planners in Sweden


Climate Change hazards are increasingly challenging the population of Sweden. The Swedish Capital Stockholm as well as rural regions, like the County of Jönköping, are looking for new ways to face climate change related problems. New urban projects (Stockholm is building 140,000 new homes until 2030) need to take increasing climate change hazards into account.

It is the goal to implement and foster a new tool to present historical as well as modelled future outcomes used in environmental monitoring. The “Green Area Factor”.


Introducing the Green Area Factor


The “Green Area Factor” improves cities’ prerequisites for adapting to climate change by promoting the green efficiency of the vegetation on the plots and the conservation of sufficient green structure. Vegetation mitigates the risk of flooding, reserves carbon dioxide, cools down the heat islands of built environments and increases the pleasantness and beneficial health-effects of the urban spaces.


In the green factor method, the urban planner sets a green factor target level for the plot that can be achieved using various green elements. The method developed for the City of Helsinki (Finnland) provides 43 different green elements relating to planted and maintained vegetation, various run-off water solutions and permeable surfaces, etc. The green factor is calculated as the ratio of the scored green area to lot area.

The goal is to provide general input, in form of suitable indicators, to decision makers from municipalities or professionals dealing with urban planning in the context of climate change and its interaction with human health and well-being and the status of the environment.


Using GAF for Stockholm and Jönköping


In Stockholm urban vegetation should be used as a climate adaptation tool. Therefore, the Green Area Factor (GAF) must be extended and validated and air pollution as well as hydrology in the GAF have to be added and combined. So ultimately the role of urban vegetation in Stockholm as a climate adaptation tool can be optimized.

These climate and environmental indicators are also essential on a regional level like Jönköping County. A CLARITY study (SWICCA) visualises future water conditions for Jönköping. Indicators in environmental management are developed and future climate conditions to be met by actions to preserve natural values are visualized and presented.

Swedish CLARITY Team discussing ways to tackle climate change hazards for urban planning.

This way knowledge for natural values can be secured and observations made in the environmental monitoring process can be explained. The indicators to check modelled data on a regional level can be used and long-term predictions of critical metrological variables for specific natural values can be made.


Problems with the Green Area Factor


The main problems with GAF are quantifying impacts of green infrastructure on air quality for different climate conditions and then translating the quantified impacts into the index scheme of the Green Area Factor.

Today, air quality is not included in GAF. But it is expected that its development will give added impetus to the utility of the tool in urban planning. It will contribute to more sustainable urban areas and it is planned to do it more cost effective.

Further, it is important to be able to visualize and download climate and health-related indicators for cities like Stockholm so that the importance of future land use change on the health of the population under the context of climate change can be assessed.

The goals are analysing the impacts of climate change and future land use (including large scale infrastructure projects) on the health of the population and the status of the environment.


Expending "GAF" to different regions


With knowledge of selected critical parameters, predictions can be made on population levels for different habitats. GAF is to be projected on different regional levels like drainage area basin, height above sea level, exposure to rain/rain shadow, county etc. In a second step, the system will be applicable to other regions. It will improve the way urban planners work today.