RO-R-4: Priority and restricted areas for special climate functions

The picture shows the view into the Stuttgart valley basin. Vineyards and woods are visible in the foreground, the residential and commercial areas are in the middle and background.Click to enlarge
In Stuttgart's periphery, cold air is generated at night and flows into the city centre.
Source: Photograph: © Manuel Schönfeld / stock.adobe.com

2019 Monitoring Report on the German Strategy for Adaptation to Climate Change

Table of Contents

 

RO-R-4: Priority and restricted areas for special climate functions

Priority and restricted areas for special climate functions are a fairly new tool used in spatial planning. This is why this area category has so far been applied in only five planning regions in Germany.

A line represents the area of the priority and reserved areas for special climatic functions in the form of indexed values. The year 2009 is set to 100. There is no trend. Up to 2011, there is a clear increase, after which the values remain at 300, in 2017 slightly below. In addition, a row of columns shows the percentages of planning regions with priority and reserved areas for special climatic functions. There is no trend here either.
RO-R-4: Priority and restricted areas for special climate functions

A line represents the area of the priority and reserved areas for special climatic functions in the form of indexed values. The year 2009 is set to 100. There is no trend. Up to 2011, there is a clear increase, after which the values remain at 300, in 2017 slightly below. In addition, a row of columns shows the percentages of planning regions with priority and reserved areas for special climatic functions. There is no trend here either. The values have remained unchanged since 2011 at just under 4.5 percent.

Source: BBSR (ROPLAMO - spatial planning monitor)
 

Conserving unsealed terrain to benefit local climate

In towns and greater conurbations with high-density settlements and a high degree of sealed surfaces, it is common to measure distinctly higher average temperatures and higher peak temperatures than in the periphery – this effect is termed ‘urban heat island’. The intensity of heat island effects increases with increasing population density. In larger towns with approximately 100,000 inhabitants the temperature difference between town and periphery can amount up to 6 °C while for the megacity of Cologne a difference of 10 °C was measured at the end of a clear night. Depending on natural bio-climatic conditions (geographical location, altitude etc), summer months can give rise to increased heat stress compared to the periphery, and climate change may lead to a future increase in the occurrence of this phenomenon. Inhabitants may experience particular difficulties owing to the rather gradual cooling of urban spaces in the evening or at night, with high temperatures making a good night’s rest impossible.

Regional planning is able to counteract this projected increase in bio-climatic stress situations by designating climatically important large-scale open areas as priority and restricted areas reserved for specific climate functions, and networking these areas where cool and fresh air accumulates with local green spaces, thus permitting the passage of fresh air into urban spaces. In this way regional planning is able to prevent any spatial usage which might counteract these objectives. Furthermore, planning can also designate areas where specific actions should be taken in view of local circumstances, in order to reduce bio-climatic stress.

It is true to say, however, that hitherto the designation of priority and restricted areas for facilitating specific climate functions has been carried out in very few regions. This is partly due to the fact that this planning category is still relatively new. Guide plans generated by state and regional planning authorities usually remain in existence over extended periods which means that innovations are only gradually incorporated into such plans.

In addition, regional planning also uses other spatial planning tools for the protection of open spaces, such as regional green belts for safeguarding climatically important open spaces; alternatively, regional planning sometimes uses a symbolic approach to illustrate bio-climatically relevant ‘air channels’ without allocating tangible tasks to specific areas. Whatever tools are used and in what way they are applied, is also dependent on the designation practice prevailing in the federal state concerned. This is why there may not be an additional demand for designating specific areas.

In the planning regions of Hesse and Rhineland-Palatinate where priority and restricted areas for specific climate functions are designated, the two objectives mentioned above are achieved by means of practical implementation: the conservation of climatically important open spaces and the designation of bio-climatically exposed areas in major need of action. In Hesse regional plans have to fulfil the purpose of safeguarding areas sustainably which can serve as climate-balancing spaces or as air channels. In the regional plans for Middle Hesse and Southern Hesse areas are specified in detail where cool and fresh air accumulates and from where such air can be channelled elsewhere, in order to safeguard and – where necessary – restore such areas. These areas are to be kept clear of development and any other measures which might inhibit the formation or transport of fresh and cool air. Plans and measures which might impair the aeration of locations exposed to climatic stress or air quality stress are to be avoided in those areas. Their implementation is permitted only in cases where evidence can be produced that no substantial detrimental climatic impacts would ensue.

The second approach within the planning category as outlined above has been adopted in the regional plan for Middle Rhine-Westerwald and in the regional land use plan for Frankfurt/Rhine-Main. In this case, thermally stressed spaces and climatically vulnerable valley locations are designated as restricted areas, partly with the objective to enhance the prevailing climatic conditions as much as possible. To this end, it is intended to conserve or expand climate-balancing areas or to avoid housing development projects which would impede the free passage of fresh air.

 

Interfaces

GE-I-1: Heat exposure and Public awareness

BAU-I-1: Heat stress in urban environments

BAU-I-2: Summer-related heat island effect - case study

 

Objectives

Guarding against overheating in towns and greater conurbations in the summer months by means of planning green belts and fresh air channels, in the context of housing developments conserving open spaces where fresh and cool air can develop and conserving channels for the free passage of this air; avoiding excessive warming of buildings and recreational areas (DAS, ch. 3.2.14)

Safeguarding climate-relevant balancing spaces and air exchange channels as well as precluding counteractive types of usage by means of specifying suitable priority / restricted areas in regional plans, for example as priority / restricted areas for special climate functions or climate-ecological balancing spaces; safeguarding climate-balancing spaces by other specifications for open spaces; spatial governance of settlement or infrastructure development, for example by means of illustrating thermal stress areas (Handlungskonzept Klimawandel, MKRO 2013, ch. 3.4)