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

Author:
  • Emma Li Johansson
  • Marianela Fader
  • Jonathan W. Seaquist
  • Kimberly A. Nicholas
Publishing year: 2016-10-11
Language: English
Pages: 11471-11476
Publication/Series: Proceedings of the National Academy of Sciences of the United States of America
Volume: 113
Issue: 41
Document type: Journal article
Publisher: National Acad Sciences

Abstract english

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.

Keywords

  • Environmental Sciences related to Agriculture and Land-use
  • Irrigation
  • Land grabbing
  • Lpjml
  • Water footprints
  • Water scarcity

Other

Published
  • ISSN: 0027-8424
E-mail: jonathan [dot] seaquist [at] nateko [dot] lu [dot] se

Head of department

Dept of Physical Geography and Ecosystem Science

+46 46 222 39 74

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Senior lecturer

Dept of Physical Geography and Ecosystem Science

+46 46 222 39 74

348

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Teaching staff

Dept of Physical Geography and Ecosystem Science

348

16

Department of Physical Geography and Ecosystem Science
Lund University
Sölvegatan 12
S-223 62 Lund
Sweden

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