The "mixed-use city": climate-friendly role model for urban development and architecture

By Alexandra Czerner (czerner göttsch architekten gmbh)

© czerner göttsch architekten gmbh

Climate-friendly urban development and climate-protection-oriented building design can produce oxygen and improve air quality at various levels. Energy saving in buildings has already been regulated in the Energy Saving Act since 1976, the current version dates from 2013. The legal regulation for adequate and appropriate urban green - regulated fairly for all urban areas and urban spaces must urgently follow suit in this respect. So far, there is no political movement that has not emphatically taken up this major issue. 

The segregation of the different functions of life was one of the major undesirable developments of the last century in terms of climate protection aspects. Long distances, especially between working and living places, generate large energy consumption with accompanying CO2 emissions and represent a large consumption of time - even a waste of time for most people. So what can be done to create a new, green, species-appropriate and ecologically balanced way for cities? With immediate political decisions for climate-friendly urban planning, both at federal and state level. This can be achieved in all countries of the "Spaceship Earth" - with ambitious regulations and laws making cities become significantly greener within the framework of their old and new structures. So let's set a good example. We have the possibilities and the know-how. Who has the courage for green urban policies that ensure better long-term living conditions for people in the ever-growing cities? 

The world is steadily urbanising. Globally, the stone cities - recognisable, among other things, by negative air parameters and overheating - contribute to the climate catastrophe - and are at the same time directly affected by its consequences. Protecting existing green spaces in cities is not enough to holistically solve the air quality and overheating problems as well as the groundwater problem in existing urban areas. 

Urban planning of the future works for ecological balance with clear greening rules and against climate change. For this, we recognise the following necessities: 

1.  To fundamentally reflect on the urban responsibility for climate change due to a lack of green spaces in cities;

2. to immediately organise urban opportunities for nature connectivity; 

3. to implement findings at federal and state levels and guarantee their implementation in a sustainable manner through binding regulations. 

Nature-conscious urban planning for climate protection

Bringing nature back into all urban spaces. Cooling roofs, facades and breaking up sealed ground surfaces, air filtration and oxygen production, supporting water cycles through infiltration and soil-bound greenery are important aspects of the green-infused and climate-protection city. 

• Create a balance per plot and building, with intensive green surfaces, because ownership obliges. This to be regulated with a binding number of green areas, secured in the Federal Land Utilisation Ordinance and in the State Building Code: implement the GRÜNFZ with an attractive set of rules. 

• Urban design: The proportion of intensive green zones per street space is to be defined and proven in relation to the total amount of surfaces. Simple and easily verifiable calculation methods are to be developed.
  
  
• Structural engineering: The proportion of intensive green zones per building is to be defined and verified in relation to the total surface area of the property and cubature. With low densities in settlements, ecologically valuable green areas are often sufficient; with higher densities, additional soil-bound façade greening and, at greater heights, object-bound façade greening as well as roof greening prove useful However, the most valuable solution for long-term green protection and the most cost-effective in terms of purchase price and maintenance costs are soil-bound plants - they are classified as the highest quality.
  
  
• Never again plan mere boundary building. For new planning include ecologically effective green front areas in all street spaces with dense, intense planting. Do not create fully sealed pavements and streets directly adjacent to fully sealed façades, but allow ground-based planting. This improves breathing air quality - which is much needed especially at cyclist, pedestrian and pram height. A few trees in the street space and a park area a few streets away won't achieve the desired results. However, for our future urban planning, the following guideline is (super)vital.
  
  
• Plan façades with an appropriate amount of greenery. Existing buildings can be retrofitted. All types of building use are obliged to contribute their share of greenery, since they all produce CO2, among other things. Purely functional commercial buildings also gain in design quality if they are enveloped in green.
  
  
• All sealed open spaces in the city are to be examined and - unless fixed by necessary use - partial areas are to be unsealed and intensively landscaped with high-quality greenery. During an attentive walk through the city, various possibilities for immediate measures become easily recognisable. If necessary, such areas can be made available to the public for greening, e.g. with concept tenders, in order to accelerate the conversion process.
  
  
• In the future, playgrounds should no longer be sealed over large areas, but should be designed in a sophisticated and unsealed way so that both play and the experience of nature can work together. In addition, play in relation to nature has strengthening effects.
  
  
• Minimise new road construction. As part of the mobility turnaround, it should be examined where new roads are actually needed.
  
  
• Examine existing traffic areas and reduce them with mobility concepts. Convert unneeded and omitted street and road areas into intensive green spaces. (current example: "Verfahren Wohnen und was noch" Hamburg, besondere Würdigung für czerner göttsch arch.Entwurf:Projekt Höpenstraße/Radickestraße.Nachverdichtung mit Erhöhung der Grünflächen u.a. durch Schaffung von einem grünen Park mit Spielflächen durch sinnvollen Verkehrsflächenreduktion ( „Housing and what else" Hamburg, special appreciation for czerner göttsch arch. design: Project Höpenstraße/Radickestraße. Redensification with an increase in green spaces, e.g. by creating a green park with play areas through sensible reduction of traffic areas).
  
  
• Allow roof gardens, for intensive greening on existing and new roofs, complementary to simple green roofs, in combination with solar collectors.  

Finally, take a look at the global situation: dying forests, fires, polluted seas etc. reduce oxygen production worldwide, while at the same time the population is growing, producing CO2 at all times in addition to CO2-emitting production processes and traffic flows. We, just like other living beings, breathe oxygen and produce CO2. The more densely the city is sealed and the more people live on limited space, the more greenery is needed for a balanced equilibrium. By only reducing the production of CO2 in various areas - a process which has unfortunately started slowly and is often stuck in the discussion phase - the climate goals will probably not be achieved. We are constantly subjected to discussions and political spectacles that frequently remain without effective consequences. The future of our children is at stake! Urban production of oxygen can help fill this gap, as an important future factor for the urban development. 

Time is pressing, as the establishment of nature and its required growth is a slowly evolving measure. 

The mass of surface - resources of the cities, still "naked" today, can soon become active partners in mitigating climate change - but only if we take care of it.

Look at your cities from above: Thousands upon thousands of square metres of "naked" facade surfaces, often dark and thus particularly heating up the climate in summer. Provided that we change our old ideas of urban planning and architecture, we could transform them into plenty of green spaces. The much-vaunted principle of voluntarism has not proved successful in the past 30 years, so why waste any more valuable time? Some funding sources remain unused, there are more than enough studies and example projects for gaining knowledge and the few existing pilot projects - in relation to the mass of new construction - do not have an effect on the masses. Talk to your politicians, ask them questions, point out the possibilities described here. We have to become loud for the good cause to achieve green successes for the benefit of our children's future and for the benefit of "Mother Earth". I quote, "We are here, we are loud, because you are stealing our future." We heard that a lot at the Friday demonstrations. Let's listen. The children are complaining, we adults are responsible to present and implement solutions. We, who have the knowledge, must act courageously. We also know that this will not endear us to everyone: As an urban planner and architect, I have also had this experience personally. Those who belong to the "urban planning classics", the representatives of today's "stone city" practice among decision-makers, would like to sort me out - and do it where they have the power to do so. I am well aware that it is difficult to rethink, to assess things from another perspective compared to the way we were once taught. But architecture and urban planning are arts and professions that should be practised with responsibility for the well-being of others, for the health of others. Are those who put their own "taste" and their learned aesthetic ideas above the future health of people, above the well-being of children, acting with sufficient responsibility? 

I would like to support anyone who would like to see a change in favour of a thoroughly oxygen-producing mixed urban quality to a "mixed-use" city. It will be possible with realistic means. I am a realist - planning and building will not necessarily become more expensive. You don't lose jobs with the measures proposed here, nor are the green measures unaffordable. We can produce the same high density of urban areas that will be needed in the cities of the future - if urban planning designs are geared to this from the outset. That’s a fact! It is incomprehensible how many new plans still today include boundary building for streets that produce hot, dry, non-percolating and fine-dust polluted urban spaces. 

Fair distribution on all shoulders can only be achieved with the appropriate legal framework. I repeat: GREENFZ, "Never again border development", mobility turnaround and traffic reduction. 

The CO2 content of the air increases, the oxygen content decreases. It is only logical to implement initiatives that neither destroy jobs nor are too costly. It is only logical to develop the cities into nature-covered "cities that grow through" in the sense of health and climate protection, which can better care for their people with oxygen production - and an achievable vision. Let's get started.