Coastal Erosion in Maldives: Is Climate Change the Only Cause?Research Project Investigates Strategies for Adapting to Sea-level Rise

7 October 2021, by CEN webmaster

Photo: UHH/CEN/B. Ratter

Small island countries like Maldives are severely affected by climate change and the resulting rise in sea level. The atolls in the Indian Ocean lie just a meter above sea level, and current projections to the end of this century call for an average global sea-level rise of more than a meter. Accordingly, adapting to climate change poses a particular challenge for vulnerable, small island countries. A research project jointly conducted by Leibniz University Hannover (LUH) and Universität Hamburg has now examined in detail the coastal processes involved, and the local population’s strategies for adapting to the progressive erosion of the Maldivian coastline. Prof. Dr. Beate Ratter from the CEN, who is a member of the Cluster of Excellence Climate, Climatic Change, and Society (CLICCS), is a co-author of the study. The findings have recently been published in the prestigious journal Nature Communications.

The experts’ aim was to determine how appropriate the adaptation strategies developed by the Maldivian government are for tackling the already pressing coastal problems and preparing for the future. The study focuses on the key question of whether sea-level rise is the sole cause of the changes in the coastline and which natural and anthropogenic processes exacerbate these changes. The goal was to more effectively deal with unwanted developments in adaptation to climate-induced sea-level rise. To do so, a team from the LUH’s Ludwig Franzius Institute of Hydraulic, Estuarine and Coastal Engineering conducted numerous field studies in Maldives to investigate the current situation on the island Fuvahmulah, and how it is changing.

The DICES research project was a successful collaboration between coastal engineering and the social sciences. Universität Hamburg (Department of Integrative Geography, Prof. Dr. Beate M. W. Ratter) used interviews with experts at the local and national level, along with several structured surveys of the local populace conducted on site, to perform a governance analysis, arriving at the conclusion that climate adaptation means more than implementing technical solutions: “When it comes to successful coastal development, the sociopolitical aspect of climate adaptation is at least as important as taking into account the natural dynamics and the political decision-making processes used by local and national stakeholders,” says Ratter. The Université de Pau et des Pays (France) also participated, providing a computer model to visualize and predict the dynamic processes involved in coastal change. The DICES project was funded by the German Research Foundation (DFG) as part of the priority program “Sea Level & Society.”

“The findings of this interdisciplinary research project demonstrate the in some cases limited adaptation capacities of small island countries when it comes to awareness of and responding to climate-induced changes,” says Prof. Dr.-Ing. Torsten Schlurmann, head of the Ludwig Franzius Institute of Hydraulic, Estuarine and Coastal Engineering at Leibniz University Hannover. “Top-down political processes with centralist models of government are often a major structural challenge in these countries. The results of our study tell us that we need to reconcile sustainable economic growth and climate change, and to more actively integrate local knowledge in order to overcome unwanted developments.”

“We also found that existing coastal engineering structures can actually contribute to coastal erosion nearly as much as the effects of climate change itself,” sums up Dr. C. Gabriel David, first author of the study and a former doctoral candidate at the Ludwig Franzius Institute, who currently works at the Technische Universität Braunschweig. Consequently, adaptation to climate change in vulnerable island countries has to be approached with great care and must reflect the natural conditions, since choosing inappropriate development measures and adaptation strategies can have significant negative effects that compound the consequences of climate change that are already being felt in small island countries, and which will become more extreme in the future.

In concrete terms, the researchers determined that a harbor built roughly 20 years ago on the island Fuvahmulah hinders natural sediment transport. Normally, this sand transport helps atolls’ coasts remain intact. “Atolls have very good means of naturally adapting to the rising sea level if their coral reefs are intact and the sediment is free to be transported or distributed naturally,” David adds. Through the sand that is washed ashore, these islands could essentially grow to match the sea-level rise. In the case of the island Fuvahmulah, however, the harbor severely limits this natural process, cutting off the supply of new sand and hindering its transport, which blocks the island’s natural protection mechanism. From the surveys taken among the island’s populace and the local government it became clear that many stakeholders are well aware of the causes and consequences, and question the wisdom of the adaptation measures chosen on a central level. “However, the Maldivian government blames the problems solely on the effects of climate change and plans to install conventional coastal protection infrastructures to address them – in part, as a tried and proven means of receiving external funding and international aid,” adds Prof. Schlurmann.

To understand the processes at work on Fuvahmulah, the LUH’s coastal engineers surveyed the coastline of the entire island, traced the sand movements and analyzed wave behavior to develop complex models that accurately simulate the island’s natural conditions and make the interventions and further consequences more transparent. At the same time, the team from Universität Hamburg surveyed the local populace regarding their awareness of and attitudes on coastal protection and climate change.