Many small and larger steps have been taken, but a lot has happened voluntarily. Now, the meanwhile undeniable climate change – the expected apocalyptic effects of the climate change have been toned down only slightly – shows that the need for action is much larger than previously assumed. Even in the USA, whose politics have always been against international environmental protection agreements, the economy and particularly the real estate industry has long been considering environmental friendly measures. Google counts roughly eleven million entries on the subject “green buildings”.

Sustainability, however, not only means reducing CO2 emissions; it covers much more. However, like most complex systems, one thing is connected on the other. The Dutch architect, Erick van Egeraat, gave an interesting definition of sustainability in the real estate industry in the widest sense of the word. He depicted a historic Mediterranean city centre (the city of Lucca) and declared, “This is my idea of sustainable development”. It was indeed the highly condensed model of the European city that unites living and working, where goods and opinions were exchanged, where public and private life coexisted in close quarters.

Although even large cities remained small long into the early 19th century, the space and number of residents are much larger today. In fact, they are often merely the core of an agglomeration that stretches far into the respective region. The development is progressing fast: In 1950, there were only two cities with more than ten million residents— Tokyo and New York City. This number rose to 22 by 2004. By 2025, according to UN estimates, five billion people – twice as much as in 1995 – will live in urban centres, with an estimated total world population of roughly eight billion people.

Thus, sustainability will mainly depend on the cities. That not only goes for future mega cities that are growing faster than their respective infrastructures can be developed; that also goes for the more developed cities inthe industrial countries, where the populations are getting older. They have to fight to keep their residents.

When sustainability will be decided in the cities, the real estate industry will have to rethink their previous strategies and approaches. Building requirements and quality standards must change, locations must be redefined, and some properties that are considered ‘hot’ today could quickly become non-sellers.

Sustainable development
A commandment of economic reason