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Chapter 1
Building a Sustainable Future
Change occurred rapidly in the twentieth centuryāmore so than at any other time period in the history of humanity. Arguably, the most significant change has been the number of people living on earth and depending on its resources for survival. Within a hundred-year time span, the global population grew from 1.6 to 6 billion, and for the first time in history over 50 percent of the populationā80 percent in the United States and Europeāis concentrated in urban areas. Cities are hastily expanding to accommodate the rapid influx. In the United States alone, 1.5 million acres (0.6 million hectares) of farmland, forest, or other rural land is being converted to urban development each year (American Farmland Trust 2009). In the coming decades, the rapid population increase is expected to continue, with projections of 7 billion in 2011, 8 billion in 2024, and 9 billion by 2045.
As human populations increase, so do the demands on the earthās resources. Unprecedented pressure is being placed on the planetās soils, waters, forests, and other natural capital (Brundtland 1987). It is projected that at current rates, humanity will soon need the capacity of two earths to absorb CO2 waste and keep up with natural resource consumption (World Wildlife Fund 2010).
To maintain their physical and mental health, every individual needs and deserves clean air, clean water, healthy productive soils, opportunities for physical activity and mental respite, and other benefits or āecosystem servicesā provided by the natural environment. Historically, we have not required urban sites to function as sustainable and productive ecosystems but instead have relied on wildlands or rural areas to provide the services that sustain human life. Sadly, two-thirds of ecosystem services are now in decline worldwide (UN Foundation 2005).
Urban sites and other developed landscapes can help reverse this trend. A sustainable future for the growing population is not out of reach, but achieving it will require dramatically changing the ways in which sites are developed and maintained. To adequately provide for the next generation, the protection and restoration of ecosystem services must become standard practice for all sitesāboth urban and rural.
Ecosystem Services: A Key Attribute of a Sustainable Site
Ecosystems provide a multitude of resources and processes that sustain and fulfill human life. These benefits, collectively known as ecosystem services, are essential to our well-being and are a key attribute of a sustainable site. Examples of ecosystem services include:
- Regulate temperature and precipitation.
- Sequester greenhouse gases.
- Cleanse the air and water.
- Provide habitat.
- Maintain soil health and fertility.
- Retain and store fresh water.
- Control erosion.
- Provide recreation.
- Recycle nutrients.
- Produce food and other raw materials such as timber, medicine, and fuel.
- Mitigate natural hazards such as flooding, wildfire, and drought.
- Provide inspiration, intellectual stimulation, and cultural enhancement.
- Enhance opportunities for mental respite.
Many of the goods and services provided by nature are often taken for granted, in large part because they are supplied for āfreeā and are not part of our traditional accounting systems. To underscore their importance and inform land-use decisions, scientists have begun estimating the wealth of ecosystem services and have found the monetary value to be an average of $33 trillion per year, or nearly twice the global gross national product (Costanza et al. 1997).
Issues that plague urban environments, such as flooding, urban heat islands, and water pollution, are often caused or exacerbated by the disturbance or removal of natural systems and the benefits they provide. Sustainable sites seek to improve the quality of life of site users and the surrounding communities by creating regenerative systems that protect and restore ecosystem services.
Regenerative Systems
The building industry has been an early adopter of the sustainability movement and has documented success in reducing energy, water use, greenhouse gas emissions, and solid waste. Although reducing environmental impacts is definitely a step in the right direction, it is not enough to provide a sustainable future for the burgeoning human population. In addition to doing less damage, we must also reverse the degradation of the earthās natural resources by creating regenerative and resilient systems that sustain and increase the provision of ecosystem services. Landscape practitioners can lead the green building movement to a higher level of sustainable design by helping project teams realize this goal and integrate living systems into all aspects of the site.
Previously developed sites that have limited ecological or cultural value present the greatest opportunity for the type of regenerative change we need. The redevelopment of environmentally degraded sites, such as greyfields or brownfields, provides a mechanism not only for protecting native ecosystems and agricultural lands (via diversion of development pressure) but also for restoring natural systems and the ecosystem services they provide. Encouraging development within existing communities and developed places also conserves the natural and financial resources required to construct and maintain infrastructure. This stands in contrast to the development of greenfield sites, which has a much greater potential of reducing or destroying healthy, functioning ecosystems and the goods and services they provide. Greenfield development that diminishes ecosystem services ultimately contributes to the global decline of natural capital and the overall benefits humanity receives from nature.
What Is Site Sustainability?
Sustainable development is commonly defined as ādevelopment that meets the needs of the present without compromising the ability of future generations to meet their own needsā (Brundtland 1987). It recognizes the interdependency between the environment, human health, and the economy and considers all three when measuring success.
The three pillars of sustainability and their...
