What is sustainability? What are the characteristics of a sustainable city?

A sustainable city is the future of city development. But what is sustainability, and why should we build sustainable cities?

From the early days of humankind to excessive consumption in the 21st century, our life on planet Earth has constantly changed.

While more commodities and comfortable living tempt people, scientists have become alarmed about the need to educate society to understand the impact of human activities and the need for more sustainable choices.

According to a new research report by Bank of America, the resources that will be most scarce in the future are water, biodiversity and air, rare Earths, and metals. But also agriculture, waste disposal, processing power, youth, health and wellness, skills and education, and time.

If we are to manage our resources better, we need to manage how sustainable we are and the cities in which we live in.

As we are gobbling up the Earth's resources at an unreplenishable rate, sustainability has become a heavily featured societal goal that aims for humans to safely co-exist on Earth for as long and as healthy as possible.

For most of us, sustainability is how we perceive what type of future we envisage for future generations, namely our children and our children's children. As discussed by the University of Alberta Office of Sustainability, sustainability is meeting our own needs without severely damaging the ability of future generations to meet their own.

The research also emphasizes that sustainability is not only environmentalism targeted at preserving natural resources. Embedded in most sustainability definitions is finding social equity and economic development concerns, as per the UN's Sustainable Development Goals (SDGs).

While there has been some battle between economic growth and environmental protection, it is essential to note that freedom, unique opportunities, and economic prosperity are not necessarily contradictory to a clean environment.

With more than 50% of the world's population currently living in cities, and the proportion of urban dwellers on the rise, sustainable living choices are significant in fast-growing metropolitan areas.

In the next couple of decades, cities worldwide will be forced to change in ways never experienced before. Sustainability will not only be an enticing feature but a driving force behind any significant metropole. The main reason cities will have to become significantly more sustainable lies not in climate change or advancements in technology but due to surges in populations.

With a projected reach of 9.8 billion people by 2050, the world's population growth presents troubling implications for the global economy, climate change, resource availability, quality of life, and many other aspects.

Despite numerous challenges, well-managed cities can be incubators for innovation and critical drivers of sustainable development.

Regarding existing cities across the globe, some are much further ahead regarding their sustainability practices. Leading the Sustainable Cities Index in 2022 is the Norwegian capital Oslo, followed closely by many other European urban cities. Tokyo, Seattle, and San Francisco were also recognized among the most sustainable cities, providing the rest of us a window into the future.

Sadly, the cost of living in such cities today is exceptionally high. Ultimately, sustainability should aid us in saving money and reducing costs. However, the initial financial burden poses the biggest drawback for most cities worldwide.

While there are many green features cities can adopt, they will need to address sustainability's social, environmental, and economic impact to be a true Earth city. Here are several characteristics that new and existing cities can achieve sustainable status.

Cities focusing on sustainability must address transportation head-on, as motor vehicles are responsible for 75% of US-produced carbon monoxide pollution. Cost-efficient and accessible public transportation takes cars off the road, reducing harmful emissions generated by daily driving commutes and errands.

As future cities inevitably become denser, the role of more localized cities will become prevalent. The aim is to reverse the urban sprawl - where development and growth occur on large swathes of land combined with low-density situations, yet significantly increase environmental impact.

An electric vehicle produces zero tailpipe emissions compared to a typical passenger vehicle, which produces 4.6 metric tons annually. For cities hoping to become carbon-neutral, vehicle charging stations for electric or other alternatives must become commonplace.

Thirty percent of the world's greenhouse gas emissions come from buildings. Green buildings reduce CO2 emissions by 32%. They also require less maintenance and have cheaper electric and water bills. These cost benefits and additional tax incentives have allowed green building construction to become widespread without government mandates.

The switch to clean energy is essential for cities to become sustainable. Solar farms can improve a city's air quality while providing citizens and municipal facilities with renewable energy. Solar energy also creates well-paying jobs and stimulates economic growth. The U.S. added 110,000 new clean energy jobs in 2018, outnumbering nearly three to one on fossil fuel related jobs.

The World Research Institute estimates that the world will need to produce 50% more food by 2050 to reduce greenhouse gas emissions by two-thirds. This unique challenge requires new future cities to feed more people via more eco-friendly means.

Over 90% of the world's urban centers are near coastal areas. While this puts these cities at greater risk of natural disasters and climate change threats, it also opens the door for better use of these nearby water sources.

Urban green spaces should be a high priority for sustainable cities, as these areas solve several challenges simultaneously. Cities can achieve pollution control, public health, and thriving biodiversity by adopting green infrastructure, all while increasing property value in the area. Parks, street trees, trails, and national parks are all examples of public green spaces.

Rather than throwing waste away only to end up in a landfill, disposal processes should be circular. Future cities must adopt recycling programs, learning from the more aggressive urban centers that have seen tremendous gains over the last 20-30 years. In San Francisco, recycling and composting mandates have helped the city reduce waste by more than 77%.

One optimal solution to reduce carbon emissions throughout a community is to have citizens ditch transit altogether. Walking and biking are great alternatives to encourage. City leaders can approve infrastructure changes, pass laws to protect cyclists, and make intelligent urban planning decisions.

Sustainable cities aren't just a lofty ideal for city planners and environmental enthusiasts. They are critical for the fight against climate change.

Flooding, damaged water supplies, heat waves, and more can be minimized by sustainable infrastructure.

As we have witnessed throughout the COVID-19 pandemic, disease spread can be limited (or even eradicated) through intelligent, sustainable urban planning.

Cities that reduce their risk of climate effects and other natural disasters will see minor property damage, insurance losses, and even casualties, making sustainable city practices necessary for long-term success.

While the need to retrofit existing buildings is critical, it's equally important to understand how the global community can build new human settlements to be more sustainable—building so-called Earth cities.

Retrofitting and rebuilding existing cities for large-scale population growth is expensive and often a high-risk investment.

Plus, the efficiency gains are marginal compared to what can be obtained starting from a blank slate.

As discussed above, cities have high living costs; thus, to retrofit them means utilizing local resources that are far more costly to rebuild.

In any such analysis, due consideration must also be given to differences not only in building new urban sustainable cities but also, as importantly, the socio-cultural conditions from which future cities are built, like the one we are making in Chile.