Climate Atlases

In the Netherlands nearly every province uses a climate atlas to base its spatial policy on. The knowledge about what the effects of climate change are and where

Fig. 2.1 The plan to develop new islands in front of the Dutch and Flemish coast (Source: Boskalis, 2008)

the effects take place is essential in taking adaptation measures. The climate atlases provide the regional governments with this essential information.

The changes in climate imply changes in the physical environment. These indirect effects, like drying out, wetting, flood risks or salination, are seen as secondary effects in the atlases. The secondary effects are dependant on the physical-geographical characteristics of an area, like relief, soil, river- and brook-system and the way an area is laid out with water discharge systems, dikes, pavements and overgrowth. For example, the sea level rise increases the chance of flooding is in the lower lying delta area of the Netherlands more than in the coastal zone near Dover. And the effects of longer periods of drought have lesser impacts in an area, which is capable of keeping water for a longer period in the area, like clay soils can, than areas that are not capable of doing so, like sandy soils. Clay soils are better capable of keeping water in the soil and do have more reserves to provide plants longer with enough water. Because of that the plants are able to survive longer in dry periods (Table 2.1).

Table 2.1 Examples of primary and secondary effects of climate change

Effects of climate change

Table 2.1 Examples of primary and secondary effects of climate change

Effects of climate change

Primary effects

Secondary effects

Sea level rise

Water surplus (wetting and annoyance)

Temperature

Water shortage (drying out and salination)

Precipitation

River discharge

Wind

The threats and challenges of the secondary affects depend largely of the projected function. For example, the effects of water shortages differ tremendously between an urban area or an agricultural area or nature reserve.

The issues on a regional level require a detailed insight in climate change at that level. Therefore, it is important that the primary and secondary are put on maps to show the consequences for different functions and what possible and desired adjustments need to be for new and existing functions.

The following issues are important:

• Are agricultural functions, nature, the water system and urban developments positioned at the most optimal places?

• Is the typology within these functions the right one on changing circumstances?

• Are the nature and water system robust enough to survive changing circumstances? Is the storage capacity of water areas flexible enough and is space enough available? Is enough room enough to provide large ecological connections and habitats, which offer new species survival opportunities?

• What are the required functional adjustments (extensions, connections, shifts) in order to keep the functions functioning?

• What are the physical and supportive structures and systems (dike systems, infrastructure) that are necessary to keep the functions function?

For each function the following questions can be formulated:

• Is the Ecological Main Structure robust enough and positioned at the right location?

• What are the best locations to develop new urban functions?

• Is the urban water system robust and flexible enough to keep on functioning in extreme weather events?

• Is the existing urban system flexible enough to adjust itself to an increase of hot days? Is it, if necessary, possible to add - temporarily - green and water in an existing urban area? And is space available in the city to position building blocks in a way that they stimulate ventilation during hot days, while protecting the public space against cold during cooler days?

The relation between primary and secondary effects of climate change is essential in understanding the required spatial measures, which affect the different spatial functions. For the province of Groningen the different effects of climate change are, in a sketch-like manner put on maps (Roggema, 2007a; DHV, 2007). This analysis aims to visualise which requirements climate change implies for the spatial development of the region. The insights are used to design the new regional plan for the province of Groningen. The maps were sketched, based on general research on the effects of climate change and the consequences in combination with expert judgements on the Groningen context. However regional climate models - based on the KNMI06 scenarios were not yet available, valuable climate proof policy options could be recommended. Figure 2.2 shows an example of such a sketch with the possible consequences of climate change for the water supply and annoyance in Groningen according the W+ scenario (KNMI, 2006).

The sketch-maps deliver insights in the consequences of climate change on different functions. This visual information, put together in an atlas, fits smoothly in planning and design processes at a regional level. The content of the climate atlases consists of maps with the primary climate effects for the year 2050, originated by the KNMI and the secondary effects. What are the changes in different climate variables (temperature, precipitation, sea level rise) and what are the effects on water surplus and -shortage and changes river discharge on different functions. The consequences of these effects for several areas typologies and spatial functions are described in the atlases (Fig. 2.3).

On top of the consequences of climate change on spatial functions the socioeconomic changes of the future are combined in an integrated spatial climate atlas

1The key in Fig. 2.2 states "Climate change according KNMI". This is not fully correct. The climate change on which this map is based shows most similarities with the W+ scenario of the KNMI06 scenarios. However, the regional climate models were not available when this map was produced.

Fig. 2.2 Sketch of the effects of climate change for water management in Groningen1 (Source: DHV, 2007)

Fig. 2.3 Climate effect atlases (Source: Alterra et al. 2007)

(Fig. 2.4). For the Dutch situation the so-called WLO-scenarios (CPB, MNP, RPB, 2006) are used to give an estimate on the socio-economic spatial claims for 2050. The combination of spatial information offers a spatial image of the adaptation task for a certain province in 2050.

Fig. 2.4 Spatial climate atlas (Source: Alterra et al. 2007)
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