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| Titel |
Applying the concept of "energy return on investment" to desert greening of the Sahara/Sahel using a global climate model |
| VerfasserIn |
S. P. K. Bowring, L. M. Miller, L. Ganzeveld, A. Kleidon |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
2190-4979
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| Digitales Dokument |
URL |
| Erschienen |
In: Earth System Dynamics ; 5, no. 1 ; Nr. 5, no. 1 (2014-01-30), S.43-53 |
| Datensatznummer |
250115293
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| Publikation (Nr.) |
 copernicus.org/esd-5-43-2014.pdf |
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| Zusammenfassung |
| Altering the large-scale dynamics of the Earth system through continual and
deliberate human intervention now seems possible. In doing so, one should
question the energetic sustainability of such interventions. Here, from the
basis that a region might be unnaturally vegetated by employing
technological means, we apply the metric of "energy return on investment"
(EROI) to benchmark the energetic sustainability of such a scenario. We do
this by applying EROI to a series of global climate model simulations where
the entire Sahara/Sahel region is irrigated with increased rates of
desalinated water to produce biomass. The energy content of this biomass is
greater than the energy input rate for a minimum irrigation rate of about
200 mm yr−1 in the winter and 500 mm yr−1 in the summer,
thereby yielding an EROI ratio >1 : 1, expressing energetic
sustainability. Quantified annually, the EROI was >1 : 1 for irrigation
rates more than 500 mm yr−1, progressively increasing to a maximum of
1.8 : 1 with 900 mm yr−1, and then decreasing with further increases
in the irrigation rate. Including the precipitation feedback arising from
changes in moisture recycling within the study region approximately doubles
these EROI ratios. This overall result varies spatially and temporally, so
while the entire Sahara/Sahel region is irrigated equally, the western
coastal region from June to August had the highest EROI. Other factors would
complicate such a large-scale modification of the Earth system, but this
sensitivity study concludes that with a required energy input, desert
greening may be energetically sustainable. More specifically, we have shown
how this type of EROI analysis could be applied as a metric to assess a
diverse range of human alterations to, and interventions within, the Earth
system. |
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