The Climate Atlas for the region of Stuttgart was published in 2008, based on the previous work in this area carried out by the City of Stuttgart since the 1980s and the in-house urban climatology department (in existence in the City of Stuttgart since 1938). The Climate Atlas provides standardised climatic assessments for the 179 towns and municipalities in the Stuttgart region. The Atlas comprises maps which show regional wind patterns, flows of cold air, air pollution concentrations, and other relevant information required to inform planners on what to do for urban climatic optimization that could inform new projects and retrofits. A key element of the Atlas is an area classification based on the role that different locations play in air exchange and cool airflow in the Stuttgart region, based on topography, development density and character, and provision of green space. The Atlas distinguishes eight categories of areas in this manner, and for each of them different planning measures and recommendations are provided.
In addition to responding to local climate characteristics, the following principles form the basis for the planning recommendations included in the “Climate Booklet for Urban Development Online – Städtebauliche Klimafibel Online”:
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Vegetation should be placed to surround developments and larger, connected green spaces should be created or maintained throughout developed areas to facilitate air exchange;
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Valleys serve as air delivery corridors and should not be developed;
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Hillsides should remain undeveloped, especially when development exists in valleys, since intensive cold- and fresh-air transport occurs here;
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Saddle-like topographies serve as air induction corridors and should not be developed;
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Urban sprawl is to be avoided;
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All trees growing in the urban core with a trunk circumference of more than 80 cm at height of 1m are protected with a tree preservation order.
The implementation of the recommendations in the Climate Atlas is carried out by the Office for Urban Planning and Urban Renewal, supported by the Office for Environmental Protection. The Section of Urban Climatology within the Office for Environmental Protection evaluates the climatic implications of intended development and larger buildings. As a result of the implementation of the recommendations included in the Climate Atlas and Climate Booklet, over 39% of Stuttgart’s surface area has been put under the protection of nature conservation orders; a record in Germany. As a result of greening actions, greenery covers more than 60% of the city. Stuttgart contains 5,000 hectares of forests and woodland, 65,000 trees in parks and open spaces and 35,000 street trees. 300,000 square meters of rooftops have been greened and 40 out of 250 kilometres of tram tracks have been grassed (as of 2007). In line with the city development vision, 60 hectares of greenfield land previously earmarked for development has been cut from the 2010 land development plan to protect existing green space. Targeted interventions such as a building ban in the hills around the town, and prevention of building projects that might obstruct the ventilation effect of nocturnal cold-air flows have resulted in preservation and enhancement of air exchange and cool air flows in the city.