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| Titel |
Reassessing the planetary boundary for freshwater consumption |
| VerfasserIn |
Dieter Gerten, Amandine Pastor, Jonas Jägermeyr, Holger Hoff, Johan Rockström, Matti Kummu |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250087605
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| Publikation (Nr.) |
 EGU/EGU2014-1663.pdf |
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| Zusammenfassung |
| This presentation reviews the conceptual and quantitative foundation of the recently suggested ‘planetary boundary’ for freshwater (i.e. the volume of human ‘blue’ water consumption that is deemed to be tolerable; see Rockström et al. in Nature 2009). It also proposes ways forward to refine and reassess this planetary boundary. As a key element of such a revision we provide a bottom-up quantification of local water availabilities taking account of environmental flow requirement in a spatially explicit manner and using five different methods to estimate these flow requirements with a global dynamic hydrology and vegetation model (LPJmL). Our analysis suggests that the planetary boundary for freshwater consumption may adopt a value of about 2800 km3 yr-1 (which is the average of an uncertainty range of 1100–4500 km3 yr-1). This is notably lower than the original suggestion based on a simpler top-down analysis that relied on some global estimates of environmental flow requirements (4,000 km3 yr-1, the lower value of an uncertainty range of 4000–6000 km3 yr-1). Although assessed with spatial detail, this new estimate remains provisional, pending further refinement by analyses of local water accessibility and further constraints up-scaled to the global domain, including study of cascading impacts on Earth system properties. Nonetheless, with a current blue water consumption of >1,700 km3 yr-1, it appears that the freshwater boundary appears is being approached fast, and perhaps faster than suggested earlier. Thus, design opportunities to remain within this boundary are imperative - we argue that their comprehensive quantification requires analysis of tradeoffs with other planetary boundaries such as those for land use and climate change. |
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