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Unintended consequences of climate change mitigation for African river basins


Emerging climate change mitigation policies focus on the implementation of global measures relying on carbon prices to attain rapid emissions reductions, with limited consideration for the impacts of global policies at local scales. Here, we use the Zambezi Watercourse in southern Africa to demonstrate how local dynamics across interconnected water–energy–food systems are impacted by mitigation policies. Our results indicate that climate change mitigation policies related to land-use change emissions can have negative side effects on local water demands, generating increased risks for failures across all the components of the water–energy–food systems in the Zambezi Watercourse. Analogous vulnerabilities could impact many river basins in southern and western Africa. It is critical to connect global climate change mitigation policies to local dynamics for a better exploration of the full range of possible future scenarios while supporting policy makers in prioritizing sustainable mitigation and adaptation solutions.

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Fig. 1: Locations of dams and irrigation districts in the ZW.
Fig. 2: Future system vulnerabilities.
Fig. 3: Analysis of socioeconomic scenarios generated by GCAM.
Fig. 4: Projected vulnerabilities of African regions.

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Data availability

All climate data are freely available at the following websites: historical precipitation:, historical temperature:, projected precipitation and temperature: (see Supplementary Table 3). Data about the socioeconomic scenarios produced by GCAM simulations are available in the Github repository: Bias-adjusted climate projections and corresponding simulated streamflow are available in the open-source repository All the historical hydrologic data on the Zambezi River basin are from the Zambezi River Authority (ZRA) and were collected during the DAFNE project ( They are protected by a nondisclosure agreement with ZRA. Source data are provided with this paper.

Code availability

The code of the HBV models is available in the open-source repository Because the Zambezi Watercourse model described in Supplementary Section 2 contains sensitive hydrologic data, along with hydropower plant characteristics from ZRA, Zambia Electricity Supply Corporation (ZESCO) and Hidroeléctrica de Cahora Bassa (HCB), it cannot be made public. The simulation outputs and the code for generating the figures can be, however, found in the open-source repository


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The authors thank A. Amaranto, B. Benigni, F. Bertoni, A. Birnbaum, F. Dolan and S. Raimondo for their contribution in developing initial numerical experiments. The authors also thank M. Mutale (executive secretary of the Zambezi Watercourse Commission) for the feedbacks provided during the DAFNE project. Co-authors M.G. and A.C. have been partially supported by DAFNE under H2020 framework programme of the European Union, grant number 690268.

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M.G., J.R.L. and A.C. designed the research and writing of the paper. M.G. and J.R.L. conducted the numerical experiments and led the data analysis. M.I.H. and P.M.R. contributed to analysis of results and writing of the paper.

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Correspondence to Andrea Castelletti.

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Nature Climate Change thanks Simon Parkinson, Raphaël Payet-Burin, Piotr Wolski and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Giuliani, M., Lamontagne, J.R., Hejazi, M.I. et al. Unintended consequences of climate change mitigation for African river basins. Nat. Clim. Chang. 12, 187–192 (2022).

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