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Move over Homo Sapiens: Homo Urbanus is here to stay

Clim8 Clim8

12 November 2021 Community

More than two thirds of humanity will eventually live in cities. To mitigate environmental pressures, governments, businesses and citizens will need to collaborate in reclaiming urban spaces and redesigning them in a circular way. But is this an urban planner’s dream, or just another false hope? 

Homo Urbanus is fast overtaking Homo Sapiens as the dominant human species. According to the UN, 55% of people lived in cities in 2018, and this migration away from rural areas to urban centres is set to accelerate. By 2030, the number of mega-cities of over 10 million inhabitants will rise by 10 to 43. And by 2050, 68% of the global population is projected to live in urban areas. 

As a result of this migration, cities are experiencing the growing environmental pressures of air pollution, waste and water management, and a general feeling that distances keep increasing. Furthermore, the UN Environmental Program’s recent work on the role of cities in global warming found that 75% of global CO2 emissions come from cities, with transport and buildings being the largest contributors to those emissions.  

If nothing changes in the way cities are designed and lived in, the future looks hot to say the least. Cities tend to be built using a lot of concrete, which traps warmth and creates an urban heat island effect, increasing temperatures. In fact, the World Economic Forum predicts that by 2050, more than 970 cities will experience average summer temperature highs of 35˚C, compared to only 354 cities reaching this temperature today. By 2050, heat waves will affect more than 1.6 billion people in urban centres, with average temperature rises of as much as 4.4˚C towards the end of the century. 

City planning is indeed essential to transform our cities into sustainable habitats. But how to get there is widely debated. Several nations have tried to build cities that do not have the structural problems of the past, such as Masdar in the UAE. Built in 2006, Masdar was meant to be a shining example of the UAE’s transition away from fossil fuels. But despite the eco-friendly LEED certified buildings, adjacent solar power plant and natural ventilation from its cooling towers, problems persist. 

For one, very few people actually live there. Despite the goal of 50,000 residents, Masdar only has a population of around 1,300. It is also extremely remote and accessible only by car. And in a country which has one of the world’s highest emissions rates per capita (ahead of heavy emitters like Australia and the US), this project seems more like a distraction than a key piece of the net zero puzzle.

By contrast, Curitiba in Brazil is a sustainable city success story. As Brazil’s 8th largest city, Curitiba boasts a population of 3.7 million people. But as the population has grown steadily since the 1970s, the city has planted more than 1.5 million trees and built 26 public parks, resulting in more than 50 square meters of green space for every person. To combat serious bouts of flooding, fields of grass were planted around the city, saving the cost and environmental expense of dams. Add to that an impressive recycling program, where residents can exchange recyclable goods for food. Due in large part to this program, residents were recycling 70% of their garbage by 1992. 

Beyond the future of energy and transportation that we already discussed in our previous COP26 blogs, one increasingly important guiding principle in city design is circularity. As French physicist Lavoisier put it, “nothing is lost, nothing is created, everything is transformed”. From rainwater collection to smart and energy-independent buildings, from urban vertical farming to soft mobility including e-bikes and improved nodal connection for public transport, the common denominator remains the same: shortening travel distances for people and things to increase efficiency and reduce waste.  

As humanity becomes more urbanised, the need to make our urban environments more sustainable will increase. While the dream of self-sustaining, futuristic cities like Masdar are admirable, it is at this point just that. Most countries do not have the resources of the UAE, nor large acreage of empty spaces to start from scratch, and therefore must be realistic and innovative about what can be achieved. Curitiba is a good example of what can be achieved without a big cheque book. 

Like many sustainability issues, the transition to sustainable urban environments will be multi-faceted, and will require action from the private and public sector. Unfortunately, it is simply not good enough to have a ‘start from now’ approach. We must go back and change the way cities currently operate, given that population growth will most likely occur in existing cities. With the help of technology, a vision that integrates people and space, and bold action, there is cause for some hope. Let’s not forget that Rome wasn’t built in a day.