17 Jan 2024
 | 17 Jan 2024

Simulating the effects of sea level rise and soil salinization on adaptation and migration decisions in Mozambique

Kushagra Pandey, Jens A. de Bruijn, Hans de Moel, Wouter Botzen, and Jeroen C. J. H. Aerts

Abstract. Coastal flooding and sea level rise (SLR) will affect farmers in coastal areas, as increasing salinity levels will reduce crop yields, leading to a loss of net annual income for farming communities. In response, farmers can take various actions. In order to assess such a response under SLR, we applied an agent-based model (ABM) to simulate the adaptation and migration decisions of farmers in coastal Mozambique. The ABM is coupled with a salinization module to simulate the relationship between soil salinity and SLR. The decision rules in the model (DYNAMO-M) are based on the economic theory of subjective expected utility. This theory posits that households can maximize their welfare by deciding whether to (a) stay and face losses from salinization and flooding, (b) stay and adapt (switching to salt-tolerant crops and enhancing physical resilience such as elevating houses), or (c) migrate to safer inland areas. The results show that coastal farmers in Mozambique face total losses of up to US$12.5 million per year from salt intrusion and up to US$800 million per year from flooding of buildings (RCP8.5 in the year 2080). Sorghum farmers may experience little damage from salt intrusion, while rice farmers may experience losses of up to US$15,000 per year. We show that medium-sized farmers (1–20 ha) are most at risk. This is because their farm size means that adaptation costs are substantial, while their incomes are too low to cover these costs. The number of households adapting varies between different districts (6 %–50 %), with salt adaptation being the most common, as costs are lowest. Despite adaptation measures, about 13 %–20 % of the total 300,000 farmers in coastal flood zones will migrate to safer areas under different settings of adaptive behaviour and different climatic and socioeconomic scenarios.

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Kushagra Pandey, Jens A. de Bruijn, Hans de Moel, Wouter Botzen, and Jeroen C. J. H. Aerts

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-17', Anonymous Referee #1, 25 Jan 2024
    • AC1: 'Reply on RC1', Kushagra Pandey, 02 Apr 2024
  • RC2: 'Comment on egusphere-2024-17', Anonymous Referee #2, 02 Feb 2024
    • AC2: 'Reply on RC2', Kushagra Pandey, 02 Apr 2024
Kushagra Pandey, Jens A. de Bruijn, Hans de Moel, Wouter Botzen, and Jeroen C. J. H. Aerts

Model code and software

DYNAMO-M salt intrusion Kushagra Pandey

Kushagra Pandey, Jens A. de Bruijn, Hans de Moel, Wouter Botzen, and Jeroen C. J. H. Aerts


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Short summary
SLR will lead to more frequent flooding, and salt intrusion in coastal areas will be a major concern for farming households that are highly dependent on the soil quality for their livelihoods. In this study, we simulated the risk of SLR and flooding to coastal farmers by assessing salt intrusion risk and flood damage to buildings.