The transboundary implications of climate-related coastal migration: state of knowledge, factors of influence and policy pathways

Submitted by Robin Hocquet | published 19th Nov 2021 | last updated 23rd Nov 2021
Two men building embankments by sea

Photo: Debsuddha Banerjee / Climate Visuals Countdown


With sea-level change (SLC), coastal human migration might become a major issue in the twenty-first century. Even if most of the mobility related to SLC will probably remain within national borders, this phenomenon raises major global-scale ethical and geopolitical challenges.

Human mobility from or to coastal areas is not a risk itself and can be an effective adaptation option, if chosen, prepared and anticipated in a fair and coordinated way by various actors. This calls for strengthened multi-level cooperation.

This study uses the case of coastal migration as an entry point to bring new elements into the debate on managing transboundary climate risks. It explores the following questions:

  • Why and how is coastal migration happening?
  • How can transboundary adaptation strategies minimize negative impacts or maladaptation (and henceforth support positive outcomes)?
  • What are the key actions to be undertaken to anticipate, prepare and facilitate such flows?
  • What are the existing policy frameworks or those to be strengthened?
  • And how to sequence them over time, from now to the longer term?

*A summary of the paper can be found below. Download the full publication from the right-hand column for more details.


The study is first based upon a desk review and assessment of existing scientific and grey literature. About 200 studies have been considered dealing with the topics of coastal impacts, coastal migration, climate migration and sea-level rise.

In addition to the literature review, semi-structured interviews were conducted with 14 international experts on coastal risks and migration.

Key messages

  • Little knowledge exists on the cascading implications of coastal migration across borders and, as a result, there is limited work on enhancing adaptive migration and relocation when relevant. Putting in place a governance framework and relevant policy tools to anticipate and prepare for migration from or to coastal areas can positively contribute to climate adaptation for migrants, the country of origin and destination.
  • This calls for an integrated approach of policies at multiple scales over time, in order to create synergies between national policies and international frameworks. This is what this study refers to as “policy pathways” (Fig. 4 in the report).
  • 5 main policy pillars have been identified to tackle the main influential factors of risks related to changing migration patterns caused by sea-level change: (i) implementation of ambitious mitigation and international support for adaptation; (ii) effective coastal risk reduction policies; (iii) robustness of migration policies allowing for planning the movement of people across borders; (iv) enhancement of hosting capacities; (v) empowerment of communities and individuals through preparedness and right to decide.
  • Cooperation between different scales of action might prove beneficial as it could foster rapid progress and coherence, while a lack of coordination and delay in implementing some policy pillars might hinder progress and have negative feedback effects (Fig. 5 in the report).


The study highlights, first, that coastal migration should not be considered as a risk in itself. If planned accordingly, migration can reveal positive outcomes for migrants, hosting communities, and the global society. However, there is currently little knowledge on the positive and negative cascading consequences of changing migration patterns across borders due to SLC. As a result, there is not enough strategic vision on policy and governance arrangements needed to facilitate adaptive solutions (including migration, when relevant) and avoid eventual maladaptation in both the countries of origin and destination.

The study highlights that managing and anticipating the cascading effects of coastal migration across borders calls for coordinated action both at the country level (country of origin and destinations) and across countries (Fig. 4), and that synergies are to be sought between national policies and international frameworks.

This way, it argues that there are strong interdependencies between policies at the national and global levels, as some decisions and policy processes at a given scale influence decision-making and action at other scales by creating positive or negative feedback loops (Fig. 5).

It therefore concludes that addressing the potential cascading effects of human coastal migration across borders calls for an integrated approach of climate change impacts and migration policies over time. This is what this study formulates as “multi-scale policy pathways’’. These pathways are a forward-looking approach, paving the way for more dialogue and cooperation between different stakeholders in the short-to-longer term, on coastal migration.

Further resources