A city is an ecosystem and systems thinking is the key to creating more sustainable cities. When we understand the functioning of human society and nature and their interaction and imitate nature, we can achieve, among other things, zero emissions and zero waste. In addition to natural sciences, human reality, psychology and sociology are of great importance if we want to build more sustainable cities.

A city is an ecosystem, like natural ecosystems. It is just an ecosystem where human activity has the greatest impact, often causing sustainability and environmental problems, such as air pollution, waste and natural degradation resulting from construction. The more a city functions like natural ecosystems, the more sustainable it is. In a natural ecosystem, energy and, for example, water are obtained from the sun and natural forces. A natural ecosystem is emission-free and carbon neutral. A natural ecosystem recycles everything. There are no substances that do not belong there naturally in a natural ecosystem. A natural ecosystem is therefore an example of a circular economy.

A sustainable urban ecosystem would therefore also get all its energy from clean renewable sources, the sun, wind and other natural forces. Its transport, energy production and industry would be electrified and emission-free. A carbon-neutral city is not impossible. When we talk about the city’s matter and energy flows, we are talking about urban metabolism. This metabolism must not produce pollution and it saves matter and energy. For example, a smart grid can save a huge amount of energy. Nature works the same way: ”reasonably sparingly”. The natural ecosystem produces its own food. A sustainable urban system gets its food from local food.

A sustainable urban system recycles everything according to the ”zero waste” principle. This recycling of everything is possible when there is a lot of energy in use. Even asphalt and concrete can be recycled when there is enough energy. By heating the material, their original structure can usually be restored. In a sustainable urban ecosystem, unnatural substances such as plastic and many chemicals are not used. The city is therefore mainly organic. Recycling is also possible in an industrial ecosystem.

Above all, a sustainable urban system is green: green and blue infrastructure or so-called nature-based solutions (NbS) produce functional ecosystem services. In general, nature-based solutions are better than technological ones. Water circulates naturally and green areas prevent flooding. Trees purify air quality and reduce extreme temperatures. In our research, trees can cool the air by up to 10 degrees during heat waves. Green roofs protect pollinating insects. It is important to protect urban nature and its biodiversity. The higher the biodiversity, the better the ecosystem services. Biodiversity is also important in itself and one of the most significant things in creating a pleasant urban space. Urban nature also enables many hobbies.

There is a surprising amount of nature in cities: for example, Berlin has 40% green cover and Helsinki 30%. Many rare species also live in cities. Greenery is crucial: when we studied the occurrence of bird species (r=100m) in Helsinki, in areas with a lot of “grey” i.e. concrete and asphalt, there were usually 2-3 species. In contrast, in parks and urban forests there were even more than 30 species. There are hedgehogs, foxes, bats in cities… so it is not just an asphalt and concrete jungle.

I want to emphasize the importance of local democracy. A city is a community where anyone with good ideas can bring about positive change, even though politics is often perceived as rigid and hierarchical. I recommend participating in local democracy in some way of your own if you have good values and ideas. Nowadays, local democracy is more inclusive than ever and there are residents’ meetings and other non-hierarchical channels of influence. For example, writing an opinion piece in a local newspaper or raising a problem on social media can also bring about change. I have personally implemented a significant initiative in the city of Vantaa to install solar panels on the roofs of schools, ice halls and other public buildings (thanks also to city councilor Tiina Tuomela). This project is already well advanced and many solar panels have been installed. I have also been able to promote more detailed biodiversity studies in connection with new construction.

Daniel Elkama