Urban sprawl and commercial agriculture continue to encroach on wild forests. Converting the natural environment for industrial and urban use causes biodiversity loss. Wild animals and plants lose their habitat, food supply, and natural protection. Urbanization also introduces harmful chemicals and invasive species that affect untouched natural land areas nearby.

Water resource depletion is another problem urban dwellers face. Developers often convert slow-moving streams into drainages. Groundwater and surface water can also be depleted for domestic and industrial purposes, leading to water scarcity.

Excessive consumption puts undue pressure on resources like trees, metals, and minerals. Some resources are not renewable, but even those renewable are being consumed faster than the Earth can renew them. Overconsumption of natural resources affects humans and wildlife.

Concepts in sustainable land use include compactness, redeveloping existing infrastructure, green spaces, and housing affordability. Eliminating unnecessary space consumption in the name of luxury and mixed-use development helps save space. Hydroponics enables space-saving urban farming, while permaculture allows agriculture to co-exist with wildlife. 

Rather than buying up virgin land, developers should consider redeveloping brownfields and gray fields. Preserving historic sites, biodiverse green spaces, and recreational open spaces should remain critical. 

Filling up every open space with buildings and factories is not sustainable. An open space can be used as a park or some other recreational purpose that promotes the well-being of residents. 

Urban growth boundary is a technique used to control urban encroachment. It involves designating certain areas of a state for urban expansion and mandating that developments are contained within them.

Cities run on energy, accounting for about 75% of global energy consumption. Sustainable energy allows cities to power development while reducing adverse environmental effects. They can save energy in all sectors, including transport, building, street lighting, and agriculture. 

Renewable energy is one of the strategies for sustainable energy use. Cities should intensify efforts to leverage solar, wind, hydro, and biomass to produce clean and sustainable energy. That would help cut back on fossil fuel emissions significantly.

Energy-efficient buildings also offer opportunities to cut back energy use, covering the construction phase and its operational life cycle. So, builders should use eco-friendly construction materials and techniques that allow natural thermal regulation and lighting.

Sustainable urban development advocates integrating biodiversity into the built environment. It aims to ensure that plant and animal communities remain resilient not as immaculate lawns and potted plants but as biodiverse ecosystems that offer ecological services.

Biodiverse green spaces, green roofs, natural waterways, bio-corridors, eco-brutalist architecture, etc, typify sustainable urban landscapes. 

To achieve that, city authorities mandate the conservation of high-value ecosystems home to critical or endangered species. They also ensure that green spaces are occupied by appropriate native vegetation that supports pollinators and small animals.

Some say sustainable cities are a utopia that can only exist in imagination. However, various sustainable practices executed across America and Europe prove possible.