Cities are iconic for our Anthropocene, the first geological epoch in which one species (Man) shapes the entire global ecosystem, with often disastrous consequences. But cities are also at the forefront of changing the paradigm of human life: not against but with nature, not mere exploitation of natural resources and gradual habitat destruction, but the maintenance of a balance between natural environment and human activity, and fairness towards future generations.

Cities today are complex ecological sub-systems and major fields of experimentation towards such sustainability goals. They concentrate ever more people in less space and seek efficiency in providing clean air and water, sanitation, healthcare and energy for all. By necessity, they become green cities so as to stem the apparent dangers of global climate change, to reduce greenhouse gas emissions, and to minimize the overall carbon footprint of its citizens.

Green cities protect green urban space and seek to increase it even further, well aware that this has positive economic consequences and positive health effects. They promote green roofs to lower temperatures in buildings. To encourage greater food resilience, they open up space for urban farming and experiment with vertical farming integrated into building structures themselves. Green cities maximize energy efficiency in buildings old and new and support energy production from renewable sources like wind, biomass or sunlight. Green cities reduce waste and have sophisticated systems of waste management. Green cities have integrated public transport systems, while also taking measures to reduce individual car traffic. Green cities have become walkable again, thereby improving the quality of life for their citizens.

Green cities are aware that sustainable development requires the interplay of economics, ecology, politics and culture. Green cities deliberately encourage life style change, but sustainability cannot be achieved without a measure of social balance and social justice, the political participation of citizens, and equitable planning processes.

“Investing in the greener, more resilient city of tomorrow is an essential insurance policy for a more disaster-prone world. It is one of the smartest, most cost-effective investments we can make in our common future.”
(UN Secretary General Ban Ki Moon)

“There will be no sustainable world without sustainable cities”
(Herbert Girardot. Creative Sustainable Cities. Totnes: Green Books, 1999, p.9)