Sustainability, Land Use and Ecological Footprints

The footprint calculation involves dividing the total land area required by the population size:

Worked Example

A city requires 4,500,000 gha of land to provide its resources and absorb its waste. The city has a population of 1,500,000 people. Calculate the ecological footprint of the city's residents.

Step 1: Identify the values.

• Total footprint = 4,500,000 gha
• Total population = 1,500,000

Step 2: Substitute into the equation.

• $\text{Ecological Footprint} = \frac{4{,}500{,}000}{1{,}500{,}000}$

Step 3: Calculate.

• $\text{Ecological Footprint} = 3.0$ gha/person

Strategies for Urban Sustainability

A city's success isn't just measured by its wealth, but by how well it balances human needs with environmental limits.

• Urban Sustainability means meeting the needs of the current population without compromising the ability of future generations to meet their own needs.
• Strategies can be large-scale, expensive Top-down Strategies (managed by governments) or smaller, community-led Bottom-up Strategies.

Cities aim to improve the Quality of Life—the general well-being of individuals—through several key strategies:

• Integrated Transport Systems: Cities link different forms of transport to reduce car dependency. London uses the Congestion Charge (£15/day) and the Ultra Low Emission Zone (ULEZ) to deter drivers, while investing £18.9 billion in Crossrail to increase capacity. In emerging cities like Lagos, a Bus Rapid Transit (BRT) system moves 200,000 people daily, bypassing heavy traffic.
• Waste Management: Freiburg in Germany recycles 88% of packaging waste and powers 28,000 homes using an energy-from-waste plant. In Lagos, Wecyclers use cargo bikes to collect waste in exchange for points (a bottom-up approach).
• Urban Greening and Housing: London aims to make 50% of its area green space by 2050. Developments like BedZED in Sutton use 50% less water and 30% less energy than the UK average, utilizing brownfield land and shared "Car Clubs" to reduce emissions.

Evaluating Sustainability and Regeneration

Rebuilding a neglected neighbourhood brings new opportunities, but it often comes at a high social cost.

• Urban Regeneration involves investing capital to revive old urban areas, such as the £9 billion Stratford 2012 Olympics project.
• Pros: Regeneration creates significant economic and environmental benefits. The Stratford project built 10,000 new homes, created 20,000 jobs, and added 10 hectares of parkland. Transport strategies like ULEZ successfully achieved 94% compliance in central London, vastly reducing airborne pollutants.
• Cons: These strategies frequently struggle with social sustainability. In Stratford, over 50% of new rents were unaffordable for original residents, leading to "green gentrification". Similarly, top-down transport fees like ULEZ place a disproportionate financial burden on low-income drivers. Additionally, waste incinerators are often viewed by local communities as eyesores or health risks.
• Concluding Judgement: Overall, while top-down environmental strategies effectively reduce emissions and waste on a large scale, they frequently fail socially by financially burdening or displacing low-income residents. Bottom-up strategies, like the Makoko Floating School (which educated 60 pupils using solar power), offer excellent social inclusion but lack the funding to make a city-wide environmental impact. A truly sustainable city must balance both approaches to protect residents' well-being.