1. World Population Prospects The 2010 Revision. http://esa.un.org/unpd/wpp/Documentation/pdf/WPP2010_Highlights.pdf.
2. Adapted from David Fridley et al., Urban RAM: Assessing the Energy Impact of Having People in Cities, 2012: http://btus.lbl.gov/sites/all/files/lbl-5740e-urban-ram-aceeejune-2012.pdf accessed July 2013.
3. http://www.ecy.wa.gov/beyondwaste/bwprog_dataWasteComposition.html. http://perigordvacance.typepad.com/files/inventoryofcarbonandenergy.pdf.
4. http://www3.imperial.ac.uk/pls/portallive/docs/1/7294712.PDF.
5. Urban quality is hard to define: definitions are dependent on a wide range of criteria that are ultimately quite subjective. A number of cities (from such diverse locations as Auckland, Copenhagen, Singapore, and New York) are frequently cited in quality of life studies, and could have served as a basis for the urban character of the 2050 City. We use New York City as the principal model for the basic urban characteristics of this study (density, amount of open green space, etc.), not least because of its familiarity to the authors.[0].