Human Appropriation of Renewable Fresh Water

Abstract

Humanity now uses 26 percent of total terrestrial evapotranspiration and 54 percent of runoff that is geographically and temporally accessible. Increased use of evapotranspiration will confer minimal benefits globally because most land suitable for rain-fed agriculture is already in production. New dam construction could increase accessible runoff by about 10 percent over the next 30 years, whereas population is projected to increase by more than 45 percent during that period.

Food Production, Population Growth, and Environmental Security

“…Aquaculture would appear to have a somewhat limited potential to replace fisheries, because its expansion is much dependent on resources derived from the oceans, such as fish meals (Folke et al , 1998). Moreover, economic limits to available arable land and renewable fresh water are being reached in many parts of the globe (FAO, 1995;Daily, 1995;Postel, et al . 1996).…”

Relationships between rapid urban development and the appropriation of ecosystems in Jiangyin City, Eastern China

“…For example, in 1998, the per capita consumption of freshwater in Jiangyin was around 168.51 t person −1 , the total amount of available global fresh water was 4.07 × 10 13 m 3 (Postel et al, 1996), and the available area of global inland waters was 3.49 × 10 8 ha (FAO, 2000), thus the area required to supply fresh water to Jiangyin = 168.51 t person −1 /(4.07 × 10 13 m 3 /3.49 × 10 8 ha) = 1.45 × 10 −3 ha person −1 . Thus, the footprint component of the city's freshwater supply equaled the product of 1.45 × 10 −3 ha person −1 and its equivalence factor, 5.06 × 10 −4 ha person −1 .…”

“…Ecological footprint analysis has been performed in two main ways: (1) by analysis of the direct appropriation of biophysical quantities (e.g., photosynthetic products) by human activities (Vitousek et al, 1986;Postel et al, 1996;Haberl, 1997), and (2) by analysis of the spatial equivalents of this appropriation of biophysical quantities (Wackernagel and Rees, 1996;Folke et al, 1997;Wackernagel et al, 1999aWackernagel et al, ,b, 2002. In recent years, the analytical methods have been greatly improved by integrating analyses of mass and energy flows into the calculations (Wackernagel et al, 2002;Bicknell et al, 1998;Ferng, 2001;Haberl et al, 2004;Monfreda et al, 2004) and by moving from static analysis at a single point in time to dynamic time-series analysis (Haberl et al, 2001;Wackernagel et al, 2004).…”

“…Ecological footprint (EF) analysis is an important approach that can be used to describe human impacts on ecosystems, and since its introduction, it has gradually matured in its concepts and methodology (Vitousek et al, 1986;Haberl et al, 2004;Wackernagel and Rees, 1996;Postel et al, 1996;Wackernagel et al, 1999aWackernagel et al, ,b, 2002.…”

Avaliação sócio-ambiental do uso de efluente de esgoto tratado na irrigação de culturas no Município de Lins - SP

“…• Ainda assim, as águas residuárias, dentro de certos limites, podem beneficiar a agricultura com outros recursos presentes, tais como incremento de matéria orgânica e aporte de nutrientes minerais interessantes às culturas manejadas IDELOVITCH, 1987 Leal (2007) menciona a importância da agricultura irrigada, atualmente responsável por 40% da produção de alimentos (TILMAN et al, 2002), como uma prática carente da adoção de cultivos e tecnologias mais eficientes no uso da água, assim como de investimentos maciços na prevenção de poluição dos corpos d'água (TILMAN et al, 2002;POSTEL et al, 1996). Neste contexto, o autor ressalta a importância do reuso de água na agricultura ligada, não somente ao sucesso de sua viabilidade técnica para promoção de melhorias agronômicas e ambientais, como também à melhoria das condições sociais mundiais, visto que essa alternativa para irrigar emerge como um potencial indispensável para garantir a segurança e incremento da produção mundial de alimentos.…”