EARTH'S CARRYING CAPACITY
An important ecocity condition is to live within ecological carrying capacity, specifically that “the city keeps its demand on ecosystems within the limits of the Earth’s biocapacity, converting resources restoratively and supporting regional ecological integrity” (www.ecocitystandards.org).
The ecological footprint measures whether we are living within ecological carrying capacity (www.footprintnetwork.org). An ecological footprint refers to the amount of land and sea area required to support a specified population at their current levels of affluence and technology (Wackernagel and Rees 1996). In short, it is a measure of demand on nature’s services relative to nature’s capacity to supply those services (i.e., its biocapacity).
The term “one-planet living” refers to a society that, on average, lives within Earth’s carrying capacity (www.oneplanetliving.org). It uses the ecological footprint to assess whether an individual or a society is living within average per -capita globally available biocapacity. If the world’s ecologically productive ecosystems were distributed across the global human population, such that each individual was attributed an equal share, and with approximately 12%
of total biocapacity set aside for nature, then each person would need to live within the ecologically productive capabilities of just 1.7 hectares of land and water area (Moore and Rees 2013).
While most of the world’s population achieves this goal, high consuming societies located mostly in Europe, North America, and Australia use much more. For example societies in Europe typically demand the ecologically productive capabilities of more than 4.5 hectares per capita while North Americans and Australians demand even more (WWF 2010). If everyone in the world lived the same way as these high consuming societies, we would need three to four additional earth-like planets to both supply the energy and resources demanded as well as absorb the wastes produced.
Since we only have one Earth, we need to learn how to live equitably within the ecological carrying capacity of this planet. Ecocities are an important part of the solution. Building cities that are compact, so as to eliminate the need and even desire to use a car, and designing the built-environment in such a way that it collects solar radiation, produces naturally ventilated spaces, harvests rainwater, and provides spaces for growing food and wildlife to flourish are all important steps.
Moore, Jennie and William E. Rees. 2013. Getting to One-Planet Living, Chapter 4 in Linda Starke ed., State of the World 2013: Is Sustainability Still Possible? A Worldwatch Institute report. Washington DC: Island Press.
Register, Richard. 2006. Ecocities: Rebuilding Cities in Balance with Nature. Gabriola Island, BC: New Society Publishers.
Wackernagel, Mathis and William E. Rees. 1996. Our Ecological Footprint: Reducing Human Impact on the Earth. Gabrioloa BC: New Society Publishers.
WWF (World Wide Fund for Nature). 2010. Living Planet Report 2010: Ecological Footprint Index. Online resource (http://www.panda.org/about_our_earth/all_publications/ living_planet_report/2010_lpr/).
In one year, humans are consuming renewable resources that take over 1.5 years to regenerate. The ecological footprint is divided into food, buildings, consumables and waste, transportation, and water. Setting a limit for the use of renewable ecological services can be directly related to energy efficiency and waste management in cities. A healthy environment is one in which the human demand for ecological services has a low impact in the supply of those services by nature.