Migration, Sea Level Rise and Climate Change

Abstract

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Accelerated sea-level rise, driven by ocean warming and land ice loss, is one of the most significant drivers of climate-related human mobility, understood as the temporary or permanent forced movement from people’s usual place of residence. Between 1901 and 2018, global mean sea level rose by 20 cm, while between 1993 and 2023 it increased by approximately 11.1 cm, tripling its rate of rise. By 2100, an additional 38 cm could be added, increasing risks for vulnerable coastal communities by intensifying the exposure of densely populated territories with limited adaptive capacity. Climate-related displacement reached 32.6 million new cases in 2022, 98% of which were associated with storms, floods, droughts and coastal erosion. Migration decisions are shaped by poverty and inequality, dependence on natural resources, increasing environmental risks and cultural attachment to place, which can delay mobility even under critical conditions. Classical migration models, such as Push–Pull and neoclassical approaches, do not capture the complexity of climate-related mobility, as they focus mainly on economic factors and do not consider resilience thresholds, anticipatory migration or trapped populations. More recent approaches integrate adaptation, vulnerability and preventive decision-making; however, no single theory fully explains the multidimensional nature of the phenomenon. In this context, the Theory of Change is proposed as a more suitable framework for designing interventions that articulate environmental risks, loss of livelihoods and human mobility, guiding action toward resilient and sustainable communities. It is concluded that the Theory of Change makes it possible to connect the nonlinear acceleration of sea-level rise, social vulnerability, livelihood loss and human mobility within a preventive pathway for adaptation, rights protection and community resilience.

Keywords: Coastal communities, Theory of Change, climate risk, sea-level rise.