Sustainable city


A sustainable city, eco-city, or green city is a city designed with consideration for the social, economic, and environmental impact, as well as a resilient habitat for existing populations. The UN Sustainable Development Goal 11 defines as one that is dedicated to achieving green, social, and economic sustainability, facilitating opportunities that prioritize inclusivity as well as maintaining a sustainable economic growth. Furthermore, the objective is to minimize the inputs of energy, water, and food, and to drastically reduce waste, as well as the outputs of heat, air pollution.
The UN Environment Programme calls out that most cities today are struggling with environmental degradation, traffic congestion, inadequate urban infrastructure, in addition to a lack of basic services, such as water supply, sanitation, and waste management. A sustainable city should promote economic growth and meet the basic needs of its inhabitants, while creating sustainable living conditions for all. Ideally, a sustainable city is one that creates an enduring way of life across the four domains of ecology, economics, politics, and culture. The European Investment Bank is assisting cities in the development of long-term strategies in fields including renewable transportation, energy efficiency, sustainable housing, education, and health care. The European Investment Bank has spent more than €150 billion in bettering cities over the last eight years.
Cities occupy just three percent of the Earth's land but account for 60-80% of energy consumption and at least 70% of carbon emissions. Thus, creating safe, resilient, and sustainable cities is one of the top priorities of the Sustainable Development Goals. Priorities of a sustainable city include the ability to feed itself with a sustainable reliance on the surrounding natural environment and the ability to power itself with renewable sources of energy, while creating the smallest conceivable ecological footprint and the lowest quantity of pollution achievable. In other words, sustainable cities should use renewable energy sources to ensure the city is energy efficient and uses clean energy without creating more pollution.

Practical methods to create sustainable cities

  • Different agricultural systems such as agricultural plots within the city. This reduces the distance food has to travel from field to fork. This may be done by either small-scale/private farming plots or through larger-scale agriculture.
  • Renewable energy sources, such as wind turbines, solar panels, or bio-gas created from sewage to reduce and manage pollution. Cities provide economies of scale that make such energy sources viable.
  • Various methods to reduce the need for air conditioning, such as passive daytime radiative cooling applications, planting trees and lightening surface colors, natural ventilation systems, an increase in water features, and green spaces equaling at least 20% of the city's surface. A 2024 meta-analysis of 182 studies across 110 cities found that street and residential trees can reduce near-ground air temperatures by as much as 12°C, with the strongest cooling effects observed in hot, dry climates and in urban areas characterized by more open morphologies. These measures counter the "heat island effect" caused by an abundance of tarmac and asphalt, which can make urban areas several degrees warmer than surrounding rural areas—as much as six degrees Celsius during the evening.
  • Improved public transport and an increase in pedestrianization to reduce car emissions. This requires a radically different approach to city planning, with integrated business, industrial, and residential zones. Roads may be designed to make driving difficult.
  • Optimal building density to make public transport viable but avoid the creation of urban heat islands.
  • Green roofs alter the surface energy balance and can help mitigate the urban heat island effect. Incorporating eco roofs or green roofs in your design will help with air quality, climate, and water runoff.
  • Zero-emission transport
  • Zero-energy building to reduce energy consumption and greenhouse gas emissions using renewable energy sources.
  • Sustainable urban drainage systems or SUDS in addition to other systems to reduce and manage waste.
  • Energy conservation systems/devices
  • Xeriscaping – garden and landscape design for water conservation
  • Sustainable transport, incorporates five elements: fuel economy, occupancy, electrification, pedal power, and urbanization.
  • Circular economy to combat inefficient resource patterns and ensure a sustainable production and consumption roadmap.
  • Increase of cycling infrastructure would increase cycling within cities and reduce the number of cars being driven and in turn reduce car emissions. This would also benefit the health of citizens as they would be able to get more exercise through cycling.
  • Key performance indicators – development and operational management tool providing guidance and M&V for city administrators currently monitor and evaluate energy savings in various facilities.
  • Sustainable Sites Initiative or SSI – voluntary national guidelines and performance benchmarks for sustainable land design, construction and maintenance practices. Key areas of focus are soil, vegetation, hydrology, materials, and human health and well-being.
Sustainable cities are creating through various means, such as:
There are a few ways sustainable cities are creating safe spaces for its inhabitants. One of the first means is decreasing urban sprawl, which is creating more opportunities for people to live within the city instead of creating more living farther from the city. In sustainable cities, this means allowing people to live closer to the workspace, which is typically in the city, downtown, or urban center. City officials are seeking new methods to increase density by changing the antiquated attitudes many suburbanites have towards inner-city areas. One of the new ways to achieve this is by solutions worked out by the Smart Growth Movement.
Another method for cities to create safe spaces for inhabitants is by educating residents of cities about the importance and positive impacts of living in a more sustainable city. This initiative boost the desire for sustainable developments, and pushes people to live in a more sustainable and environmentally-friendly way.Recent research proposes that cities can be conceptualized as having an "urban genome" — a coded architecture of service protocols, infrastructure, and governance rules. When analyzed through data integration and artificial intelligence, this framework enables predictive, adaptive, and cross-sector planning toward more sustainable, resilient, and inclusive urban systems.
The final method to note is policy and planning changes to meet the unmet demands for urban services. Some of these services include water, energy, transport, depending on the city and its needs.
With regard to methods of emissions, counting cities can be challenging as production of goods and services within their territory can be related either to domestic consumption, or exports. Conversely, the citizens also consume imported goods and services. To avoid double counting in any emissions calculation it should be made clear where the emissions are to be counted: at the site of production or consumption. This may be complicated given long production chains in a globalized economy.
Moreover, the embodied energy and consequences of large-scale raw material extraction required for renewable energy systems and electric vehicle batteries are likely to represent its own complications. For example, local emissions at the site of utilization are likely to be very small but life-cycle emissions can still be significant.

Architecture

Buildings provide the infrastructure for a functioning city and allow for many opportunities to demonstrate a commitment to sustainability. A commitment to sustainable architecture encompasses all phases of building including the planning, building, and restructuring. Sustainable Site Initiative is used by landscape architects, designers, engineers, architects, developers, policy-makers, and others to align land development and management with innovative sustainable design.

Eco-industrial park

The UNIDO defines eco-industrial park as a community of businesses located on a common property in which businesses seek to achieve enhanced environmental, economic, and social performance through collaboration in managing environmental and resource issues. This is an industrial symbiosis where companies gain an added benefit by physically exchanging materials, energy, water, and by-products, thus enabling sustainable development. This collaboration reduces environmental impact while simultaneously improves economic performance of the area.
The components for building an eco-industrial park include natural systems, more efficient use of energy, and more efficient material and water flows. Industrial parks should be built to fit into their natural settings in order to reduce environmental impacts, which can be accomplished through plant design, landscaping, and choice of materials. For instance, there is an industrial park in Michigan built by Phoenix Designs that is made almost entirely from recycled materials. The landscaping of the building will include native trees, grasses, and flowers, and the landscaping design will also act as climate shelter for the facility. In choosing the materials for building an eco-industrial park, designers must consider the life-cycle analysis of each medium that goes into the building to assess their true impact on the environment and to ensure that they are using it from one plant to another, steam connections from firms to provide heating for homes in the area, and using renewable energy such as wind and solar power. In terms of material flows, the companies in an eco-industrial park may have common waste treatment facilities, a means for transporting by-products from one plant to another, or anchoring the park around resource recovery companies that are recruited to the location or started from scratch. To create more efficient water flows in industrial parks, the processed water from one plant can be reused by another plant and the park's infrastructure can include a way to collect and reuse stormwater runoff.