Climate change and the garden city movement
By Dr Matthew Bradbury
The environmental impact of climate change on the world’s cities will be an enormous challenge to landscape architects. The atmosphere is warming, increasing the capacity to hold more water and causing more rainfall. Widespread flooding will be the result.
The increase in air temperature also leads to the melting of the ice caps. This will have the effect of rising sea levels. According to the Intergovernmental Panel on Climate Change, sea levels are expected to increase by 1.00 m by 2100. However, their figures have recently been reconfigured, and now the sea level is expected to grow by 2.000 mm. The result will be increased coastal flooding and an increase in littoral damage from storm surges. The warming of the atmosphere will cause more heatwaves, raising the temperature to levels that will be intolerable to human life. The cumulative effect of these environmental changes on the biodiversity of the world’s flora will also be profound; many native species are in danger of extinction due to adverse environmental effects.
Auckland. Image by Claudio Silvano from Pixabay.
Climate change will have two specific effects on urban hydrology. The first will be an increase in runoff from impervious urban surfaces. The runoff will pick up contaminants from roofs, roads, and footpaths. The discharge of this untreated water into urban streams and waterfronts will increase the pollution of the receiving environment, such as lakes and harbours. The effect of the increased runoff will also be widespread urban flooding.
What are the implications of these conditions on contemporary urban design? The current urban planning model emphasises urban density through a grid infrastructure network and an intensive building programme. The antecedents of this model are found in the ideas of New Urbanism. The model has developed into a highly successful urban typology, often called the compact city, replicated globally. The success of this formula is due to how the recipe has been adapted to the exergies of real estate planning. While this model has proved to be enormously successful both socially and economically, the consequences are that the new urban design formula is highly impervious. The contemporary urban model emphasises hard surfaces, roads, infrastructure, footpaths, bike lanes and complex public spaces; squares and plazas. The hydrological consequences are profound: with the paucity of green space, there will be little ability to absorb the increased runoff due to climate change. Urban pluvial flooding and stormwater contamination will increase. The typical hard-impervious coastal edge will also exacerbate the effects of coastal flooding. With climate change, these three hydrological conditions, contaminated stormwater, pluvial flooding and sea-level rise, will become much more insistent in any attempt to design the contemporary city safely.
Tapiola in Finland. Image credit - Global Garden Cities.
Landscape architects may feel concerned about the hegemony of the compact city model, which seems inadequate to respond to the severe challenges that climate change poses but looks as if it will exacerbate these effects. At first glance, a new urban design model would seem to be called for, one which is less dense and with more significant areas of impervious surfaces with greener absorbent spaces. Where might this new model be found? As it happens, there is an urban development model that could allow for the exergies of climate change through a more significant, more equal relationship with the landscape. This is the urban movement that we call the garden city. The history of the garden city offers a different but equally valid model of urban development for the 21st century. The garden city starts with the idea of an equal relationship between the environment and building form. The concept of living within a landscape, either natural or artificial, garden or park, was initially advanced as a panacea to the appalling urban conditions of the 19th-century city. The idea's genesis starts at the turn of the 19th century; however, the picture has taken many forms since then.
This history draws on two critical perceptions, the theoretical insight of Ebenezer Howard, that the landscape can organise the urban realm and that of Le Corbusier, that the city might be contained within a single building that stands within nature. The post-war European new towns examples demonstrate the many different possibilities of these two ideas.
This new relationship between the city to nature started with the publication of The Garden Cities of Tomorrow at the beginning of the 20th century. The author, Ebenezer Howard, is horrified at the phenomena of the late 19th city, the terrible social and environmental conditions. His solution is a new urban form, a middle way between the industrial 19th-century town and living in the countryside. Howard avoids making a specific plan for the new city; he hardly mentions gardens. Instead, he uses a diagram to explain how the problem of developing a new city organisation can be conceived.
Leys Walk, Letchworth Area Guide. Picture: DANNY LOO
The building of the town of Letchworth in Hertfordshire was the first physical realisation of Howard’s garden city idea. The landscape of Letchworth, the ‘garden’ of the garden city, was the result of two ideas Firstly, a romantic, literary view of the landscape and garden and secondly, strict zoning regulations. In Howard's book, a garden is simply a generic form allied to the diagram. Howard stripped the idea of the garden of all its associated meaning, leaving it open to new possibilities. Elided of any definite description, the garden can now adopt other forms, a park, a belt, a street, a city. Letchworth demonstrates the landscape possibility of this potent diagram, linking the private residential garden, the planted public road, and the nature/reserve to make a new urban model, the garden city.
The garden city became a tremendously powerful urban model that was endlessly malleable and able to adapt to different political situations, from social democratic Weimar Berlin to colonial New Delhi and yet keep the original formal relationship of citizens to the landscape.
The other great theorist of a new relationship between nature and the city is Le Corbusier:
Then suddenly, we find ourselves at the feet of the first skyscrapers. But here we have, not the meagre shaft of sunlight, which so faintly illuminates the dismal street of New York, but an immensity of space. The whole city is a park. The terraces stretch out over lawns and into groves… Here is the CITY with its crowds living in peace and pure air, where noise is smothered under the foliage of green trees… Here bathed in light, stands the modern city.
Le Corbusier developed these ideas with the plan for a Contemporary City based on a super-sized grid laid over a level site, surrounded by a protected zone of woodland and fields. The centre of this gridded city was a multilevel transport interchange, surrounded by a large park supporting twenty-four, sixty-storied towers in a grid point pattern. Surrounding this central area was a perimeter of housing blocks of two types: a traditional perimeter block with a large courtyard/garden/recreation area in the centre and a more open linear kind of block with a large return or resident along the perimeter. A green belt encircled the new city. With the design of this city, Le Corbusier develops two critical urban tropes; the first is the invention of a new urban type, the tower in the park, The second is the development of the building as a self-contained city that is located in the landscape with a direct relationship to an unmediated nature.
These discoveries had a powerful effect on the planning and architecture of the post-war European city, as can be seen in four examples: Alton West, Roehampton, London, England, Vallingby, Stockholm, Sweden, Tapiola, Helsinki, Finland, and one of the first new towns Harlow, England. All these projects were initiated and began construction in the 1950s.
Welwyn Garden City in the UK was the second garden city created. Image credit - Global Garden Cities.
The design of the town of Vallingby, Stockholm, Sweden, is a combination of housing slabs and towers tare arranged around a central park, Grimstaskogen. This public space is a nature reserve that retains the indigenous landscape, helping to build urban biodiversity. The lake in the centre of the account acts as a detention zone for flooding.
To the southeast of the Finnish new town Tapiola, across Otsolahti Bay, is the suburb of Itaranta. Here the housing is less dense, with single story terraces sited along the lower contours and five apartment towers, designed by Alvar Aalto (1962 -67) in a distinctive fan shape, sited along the rocky ridge Itaranta, the high point of the site. The building is placed within an indigenous forest of pines and black alders.
In the two Scandinavian towns, Le Corbusier's tower in the park idea means the residential tower is placed within a natural landscape of rocks and forest. The buildings are used to engage and emphasise the natural topography.
In the English new town Harlow, the landscape architect Sylvia Crowe planned the city with the housing and factories divided by 'green wedges', small valleys preserved in the city's construction. Crowe augmented the environmental programme of the wedges by concentrating play areas, pedestrian links and school sports fields in these landscapes. The wedges also act as a link between the town and the countryside.
The Alton West Estate on Roehampton Hill overlooking Richmond Park was influenced by the recent construction of the Unité d'Habitation in Marseilles 1947-52 by Le Corbusier. The first Unité was Le Corbusier's attempt to fold all the functions of the city into a self-contained singular building that would have an unmediated relationship to the natural world. By raising the building on pilotis, Le Corbusier denied any building relationship to their surroundings.
In the original scheme, the buildings, five 11 story maisonettes, would form a line along the ridge; In the final project, the buildings were rotated 90-degree so as not present a prominent ridge ‘wall’ over the landscape. Instead, the five buildings were positioned at right angles, the ground dropping away as the building rose above the landscape on piloti.
The two English housing estates engage with the traditional English landscape, the rolling hills and valleys. The green wedges of Harlow preserve the natural topography of the landscape, using the terrain to organise the city plan ensuring all citizens have access to green space. Similarly, the slabs of Roehampton leave the natural topography untouched. The result is that the slab block gives the same density as the traditional city block but with a much smaller footprint, preserving the natural landscape.
What are the implications for the design of cities in Aotearoa? A recent design studio at UOA run by Steve Hutana, Tracy Ogdon Cork, George Clarke, might give us some clues.
Nga tohu o te Whenua - The Vertical Papakainga design studio is an exploration of how a new model of indigenous housing could be reimagined as a vertical papakāinga. One project by X rethinks the typical urban organisation of a city block to fold marae and housing together. The building programme is clustered and extruded, leaving what is in effect an extended atea.
The implication of these urban types for developing an urban model that is resilient to climate change is far-reaching. Landscape architects can draw upon a rich history of the theory and practice in the ways that the landscape and city can form new kinds of urbanism that use natural systems to build resilience to the environmental deprecation of climate change while at the same time ensuring a rich urban life.