Sustainable buildings are a technical standard today. Now the time has come to focus on sustainable cities as a whole. This includes the production of energy as well as the management of all resources and the use of urban space for agriculture. To make sustainable cities possible, it requires public as well as private investment.
LISDAR’s second day focussed on architecture, infrastructure and investment, as cities are the most important sources of CO2 emissions. Participants were welcomed by Renate Muessner, Liechtenstein’s Minister for Spatial Development. She highlighted that Liechtenstein is putting a lot of emphasis on sustainable development. Space is one of the scarcest resources in Liechtenstein, so it must be used wisely. The energy used in buildings should be reduced and buildings themselves should be designed to produce their own energy.
Green cities go beyond green buildings
The future belongs to renewable cities and regenerative regions, as LISDAR’s Chair Peter Droege pointed out. Since energy-positive buildings have already become a technical standard, it is now time for whole cities to become energy positive. Regenerative regions already exist in many countries. The technical possibilities are there. Now it is time to use them. 
Architects are among those who have to take the lead. Not only does this make ecological sense, but economic sense as well, said Stefan Behnisch, Principal of Behnisch Architekten. Responsible urban architecture is a sound corporate strategy for architects.
And for whole cities, too: The City of Stockholm has turned an old industrial area into an eco-quarter. Today, Hammarby Sjöstad attracts visitors from all over the world, as Stockholm City Urban Development Director Ingela Lindh told the audience. More importantly, Hammarby Sjöstad is a place where people want to live, even if not all of its ecological goals have been met. Hammarby’s success depended on many factors, including the central role played by the city and the cooperation of public and private companies.
Many of the largest and the fastest growing cities, however, are in Asia. Urbanisation in the Asia-Pacific has brought on a looming water and space crisis, says Steffen Lehmann, Professor at the University of South Australia and Director of Zero Waste South Australia. But there are solutions at hand: renewable energy sources, a less polluting public transportation network that minimises the chaos of large urban centres, and a new understanding towards optimising material flow. The evolution of technology is presenting new perspectives for all cities, but
social and cultural aspects must be included too.
Both public and private financing needed
One of the biggest challenges, however, is financing these sustainable cities and sustainable infrastructure. Sustainable cities need both public and private financing, says Kaarin Taipale, researcher at the Center for Knowledge and Innovation Research at the Aalto University of Economics in Helsinki. And yet the perspectives of each side are different. From the point of view of public budgets, real estate tax related to energy efficiency, cross-subsidies or fees dependent on resource consumption are examples of how sustainability principles can be introduced in the financing of cities and metropolitan regions. But from the point of view of private investment, real estate development is a long and complex process. Instead of prioritising sustainability, investors prefer to calculate risks. This means that sustainability criteria are increasingly being introduced under the guise of risk management, whereby several categories of risk can be described. 
Roger Baumann is an investor from the private side. According to the Head of Business Development and Sustainability at Credit Suisse’s Real Estate Asset Management department, sustainability is turning into one of the major competition drivers for the real estate market in Europe. Energy and resource efficiency, as well as regard towards the well-being of a building’s users, results in lower operating costs, lower vacancy risks and more productivity per user. There are many labels around the world for sustainable buildings such as LEED, BREEAM and Minergie (in Switzerland). Credit Suisse takes Minergie certification into consideration, but independent experts award their own quality seal for green property financed by the bank.
Agriculture comes back to the city
It is not enough to make construction and infrastructure sustainable. Nature needs space as well, as Carmen de Jong of the University of Savoy’s Mountain Centre in Chambery explained. Eco-productive regions in the Alps encompass soil, water and air. Eco-productivity has shifted considerably over the past 100 years through land-use change. In the future, even greater shifts in values are to be anticipated due to climate change, water scarcity, pollution, the development of ski resorts and urban areas, as well as changing socio-economic values. To enhance and maintain eco-productivity, resources have to be carefully conserved, decontaminated and protected from further pollution.
As Hans-Peter Schmidt pointed out, soil quality has deteriorated over centuries due to human use. The time has come to reappropriate space in cities and villages for nature, said the Delinat Institute’s Research Director. There are many examples already: roof gardening, wall gardening, social gardening, even guerrilla gardening, to name a few. Whatever form takes, it increases the quality of life.
This new trend requires collaboration between urban planners, architects, engineers, social workers and entrepreneurs alike, says Viraj Puri, Partner at Gotham Greens in New York City. Together they can develop urban agriculture operations in empty lots, rooftops and in multi-story skyscrapers. Gotham Greens, a New York City based company, has built a huge glasshouse on the rooftop of an old industrial building in New York City. The glasshouse could serve as a model for similar undertakings around the world. It saves land and water, improves food safety and cools the building, among other environmental advantages. Its lettuce, herbs, tomatoes, cucumbers, strawberries and beans are sought after throughout New York – one of the few sources of truly local food in that city.