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Green and blue water demand from large-scale land acquisitions in Africa

Johansson, Emma Li LU ; Fader, Marianela; Seaquist, Jonathan W. LU and Nicholas, Kimberly A. LU (2016) In Proceedings of the National Academy of Sciences of the United States of America 113(41). p.11471-11476
Abstract

In the last decade, more than 22 million ha of land have been contracted to large-scale land acquisitions in Africa, leading to increased pressures, competition, and conflicts over freshwater resources. Currently, 3% of contracted land is in production, for which we model site-specific water demands to indicate where freshwater appropriation might pose high socioenvironmental challenges. We use the dynamic global vegetation model Lund-Potsdam-Jena managed Land to simulate green (precipitation stored in soils and consumed by plants through evapotranspiration) and blue (extracted from rivers, lakes, aquifers, and dams) water demand and crop yields for seven irrigation scenarios, and compare these data with two baseline scenarios of staple... (More)

In the last decade, more than 22 million ha of land have been contracted to large-scale land acquisitions in Africa, leading to increased pressures, competition, and conflicts over freshwater resources. Currently, 3% of contracted land is in production, for which we model site-specific water demands to indicate where freshwater appropriation might pose high socioenvironmental challenges. We use the dynamic global vegetation model Lund-Potsdam-Jena managed Land to simulate green (precipitation stored in soils and consumed by plants through evapotranspiration) and blue (extracted from rivers, lakes, aquifers, and dams) water demand and crop yields for seven irrigation scenarios, and compare these data with two baseline scenarios of staple crops representing previous water demand. We find that most land acquisitions are planted with crops that demand large volumes of water (>9,000 m3·ha-1) like sugarcane, jatropha, and eucalyptus, and that staple crops have lower water requirements (<7,000 m3·ha-1). Blue water demand varies with irrigation system, crop choice, and climate. Even if the most efficient irrigation systems were implemented, 18% of the land acquisitions, totaling 91,000 ha, would still require more than 50% of water from blue water sources. These hotspots indicate areas at risk for transgressing regional constraints for freshwater use as a result of overconsumption of blue water, where socioenvironmental systems might face increased conflicts and tensions over water resources.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Irrigation, Land grabbing, Lpjml, Water footprints, Water scarcity
in
Proceedings of the National Academy of Sciences of the United States of America
volume
113
issue
41
pages
6 pages
publisher
National Acad Sciences
external identifiers
  • scopus:84991453536
  • wos:000384886900057
ISSN
0027-8424
DOI
10.1073/pnas.1524741113
language
English
LU publication?
yes
id
9167031f-883f-4d2a-8d1c-aae7cdbd3da5
date added to LUP
2016-10-31 12:18:49
date last changed
2017-08-13 04:59:46
@article{9167031f-883f-4d2a-8d1c-aae7cdbd3da5,
  abstract     = {<p>In the last decade, more than 22 million ha of land have been contracted to large-scale land acquisitions in Africa, leading to increased pressures, competition, and conflicts over freshwater resources. Currently, 3% of contracted land is in production, for which we model site-specific water demands to indicate where freshwater appropriation might pose high socioenvironmental challenges. We use the dynamic global vegetation model Lund-Potsdam-Jena managed Land to simulate green (precipitation stored in soils and consumed by plants through evapotranspiration) and blue (extracted from rivers, lakes, aquifers, and dams) water demand and crop yields for seven irrigation scenarios, and compare these data with two baseline scenarios of staple crops representing previous water demand. We find that most land acquisitions are planted with crops that demand large volumes of water (&gt;9,000 m<sup>3</sup>·ha<sup>-1</sup>) like sugarcane, jatropha, and eucalyptus, and that staple crops have lower water requirements (&lt;7,000 m<sup>3</sup>·ha<sup>-1</sup>). Blue water demand varies with irrigation system, crop choice, and climate. Even if the most efficient irrigation systems were implemented, 18% of the land acquisitions, totaling 91,000 ha, would still require more than 50% of water from blue water sources. These hotspots indicate areas at risk for transgressing regional constraints for freshwater use as a result of overconsumption of blue water, where socioenvironmental systems might face increased conflicts and tensions over water resources.</p>},
  author       = {Johansson, Emma Li and Fader, Marianela and Seaquist, Jonathan W. and Nicholas, Kimberly A.},
  issn         = {0027-8424},
  keyword      = {Irrigation,Land grabbing,Lpjml,Water footprints,Water scarcity},
  language     = {eng},
  month        = {10},
  number       = {41},
  pages        = {11471--11476},
  publisher    = {National Acad Sciences},
  series       = {Proceedings of the National Academy of Sciences of the United States of America},
  title        = {Green and blue water demand from large-scale land acquisitions in Africa},
  url          = {http://dx.doi.org/10.1073/pnas.1524741113},
  volume       = {113},
  year         = {2016},
}