Since the first Neolithic settlements that emerged together with agricultural practices and the new ways of social organization, city models have significantly evolved. The first relevant urban centers of Middle East dictated the way in which future settlements would develop, being spread through the Mediterranean by the Greeks, Phoenicians and Carthaginians.

Romans made the first breakthrough, establishing two main ways within the city and building sewerage, paved roads and drinking water through channels and aqueducts.

Feudalism was present during the Middle Age. Throughout this period, cities became concentric urban conglomerates that spread in an organic fashion, with an irregular layout of narrow streets, lacking any kind of urban planning and regulation.

The following key period was Industrial Revolution. Along with the new industries, precarious neighborhoods for the working class appeared, resulting in the development of new urban plans.

The main proposals to such working neighborhoods and city densification were twofold: First the “Widening” and second, the “City garden”.  Widening involved the augmentation of the city framework in an orderly fashion through a grid structure. In contrast, city gardens would bring residences to the city outskirts, creating the so-called “residential areas” with better standards of living. City gardens were regarded as a better solution. Yet, this option exacerbated transportation problems as left taking the car as the only alternative to move around.

Pic.1: Barcelona, contrast between “El Ensanche” and the old town (geografiamungia.wordpress.com)

In the middle of 20^th century, the concept of green cities arose in response to the previous urban planning concepts which proved to be wrong. It became clear that cities should blend into the landscape in an ecological and sustainable way. Since then governments have changed their mindsets and urban layouts have seen significant changes.

The development of this idea has been global, working always as a response to the major current problems of cities. Such problems can be grouped into five different categories:

• Traffic: This is a problem inherent of big cities. In any of these, it can be clearly seen how citizens have lost their prominence with respect the city giving their way to cars, which rule the city. Owing to this situation there are problems such acoustic contamination (we can constantly hear the noise of engines at any given time, but we are not even aware of it), the stress generated by the traffic, or the well-know contamination from cars’ emissions.
• Waste: Consumerism, the small durability of goods and the comfort level of the average citizen lead to increased waste levels which are much more elevated than in any other place.
• Population density: The speed of growth, the price of land and the increase of distances have conditioned the city to grow vertically. This creates a feeling where citizens’ space of living decreases more and more each day.
• Low energy efficiency: For generations innovations in construction are going towards safer and more aesthetic cities, creating buildings that required heating during winters and cooling during summers, and electric illumination all day long.
• Developing cities’ growth: This is a serious problem of those cities in developing countries as they do not have enough resources to adapt to the rampant growth that they are experiencing. Because of this, city’s expansions have led to the creation of slums, where crime, illegal settlements, inequality and unhealthy living conditions are ubiquitous.

For all these reasons, urban planning needs a change. There is a need for new transportation models, large green areas which should work as release valves to face the reality of sustainable and efficient buildings. We will have to make the most of utilized spaces in the city, promoting citizens equity while adapting the cities to the current growth. With this in mind, the European Union is leaning towards multi-centered cities with uncertain limits while city centers are re-equipped.

To achieve these goals, urban policies need major changes with creative and innovative solutions such the following ones:

• Transport model renewal: In essence, this idea is based in two concepts: First, the massive use of bicycles and second, public transport systems based on clean energy. Although the use of bicycles depends on social acceptability, citizens’ habits, climate and topography, its use will be crucial in the new cities. Due to this, cities as Vancouver have even proposed creating bicycle highways.
• Citizens’ involvement: Make citizens part of every decision, giving them back a more prominent role in the decision-making process
• A more effective use of resources: New cities should make the most of available resources (spaces, sources of energy, water, local products…). This is a problem that affects city centers in particular. Currently, it is sought that the neighbors are the ones who make decisions on the use of these spaces, since they know best the surroundings. Most common proposals comprise parks and ecological vegetable garden.
• Reduce waste: Current theory is based on reducing, recycling and reusing. Reducing the products that we consume and their envelopes and recycle them so they can be re-used.
• Large green spaces: This is important for both, the creation of big parks and the recovery of former green spaces.  We should be aware that each park must adapt to the surrounding environment.
• Sustainable buildings: Energy efficiency must prevail in new buildings, especially with regard to air conditioning in order to reduce the energy cost associated to this. In order to do so, buildings will have to have enough ventilation. Keeping natural heat during the winter, repelling it during the summer and incorporating generators based on green energies in order to create autonomous buildings.

Pic 2: Example of Green City. (www.seresponsable.com)

Given that there are no one-size-fits-all solutions, we will need to develop all these concepts simultaneously including: changing the transport model, reducing products and waste, recycling, creating green areas and improving energy efficiency.

Such changes should happen together with a social evolution, new urban layouts with multiple city centers, easing citizens’ mobility so that they can carry out their day-to-day life in accordance with the concept of Green Cities.

Rafael Villegas

Gonzalo Pastor

Universidad Politécnica de Madrid