Climate Change and Migration: A Modelling Approach

Climatic Change, 2008

Previous research has postulated that climate change will lead to mass migration. However, the linkages postulated between the two have not been explicitly demonstrated but have rather been derived from 'common sense'. In this paper, the connection between climate change and migration via two mechanisms, sea level rise and floods, is investigated and depicted in conceptual models. In both cases, a connection can be traced and the linkages are made explicit. However, the study also clearly shows that the connection is by no means deterministic but depends on numerous factors relating to the vulnerability of the people and the region in question.

2021

Global trends in migration show a predominance of internal over external flows. The African continent is the world’s most vulnerable region to climate change due to its higher levels of exposure and its scarcer financial resources for adaptation. Therefore, climate change presents in Africa some peculiar challenges to livelihoods, and security. In this paper, we assess the climate-induced migration in African coastal zones, accounting for many different factors such as conflict, demography, social networks, economic opportunities, and geographical factors such as the terrain. We also provide a critical review of major strands of models of climate-induced migration, namely agent-based models, choice-centred models, gravity model, and household allocation models. The most used data in climate change analyses are also analyzed.

Advancing Social Simulation: The First World Congress, 2007

Environmental issues pose enormous risks for all populations, but especially for the vulnerable. There have been many attempts to measure the risks and the costs of environmental episodes. Such measurement is seen in many quarters as a matter of increasing urgency as a result of the prospect of climate change. The economic approach to vulnerability measurement is based on cost-benefit analysis (CBA). CBA itself is predicated on the proposition that all relevant impacts of climate change can be given a numerical value. A clear argument for this approach was offered by the late David Pearce [13]. The value to be chosen is what the "market" value of the marginal costs and benefits. Where there is no relevant market, individuals must be able to state what they would pay to be able to stay where they are or the money they would accept as an inducement to move from where they are. In many, perhaps most, cases valuation is by no means so simple since actions are taken in response to environmental and political events. In this paper, we investigate one such case concerning the Sahel region at the edge of the Sahara. In the Sahel 1 , typically individuals migrate but who migrates and whither they migrate is a household decision. It would be remarkable if such decisions taken by one household were not influenced by the behaviour of other households. Consequently, any attempt to value migration will depend not only on environmental and political events of the moment but also on the social norms that emerge as household decisions are reached and as those decisions are discussed among members (or heads) of households in the same communities. This sort of social decision making does not fit easily with the sort of economic theory with its monetization arguments on which CBA is based.[8] Due to the way a standard economical approach measures and evaluates cost and benefit, lots of social context in the examined domain gets lost. This social context, in its turn, might have a significant influence on the outcomes of the CBA results and thus be never evaluated. The core question addressed in this paper is whether and how agent-based social simulation can provide a superior alternative to conventional economic analysis. In particular, do models constrained by evidence rather than simplistic theory provide a better guide to policy? The model reported here demonstrates that the answer to this question is in the affirmative. 2 The evidence 2 The Sahel is subject to the greatest climatic variation of any region in the world 3. One feature of this variability is the unpredictable occurrence and duration of droughts. Several studies [1, 14] have assessed the impact of intermittent droughts and their resulting catastrophic effects. These circumstances of the case offer a good testbed for validating the theories postulated by this paper about agent-based modelling being a better alternative to CBA than a conventional economic approach. CBA will be 1 The sourthern edge of the Sahara desert covering parts of Mali, Nigeria, Senegal, Chad, etc. 2 The descriptive verbal evidence used in the design of the model reported here came entirely from Stockholm Environment Institute Oxford office, [14, 5, 1]. 3 The reasons are not fully understood but see [10, 9, 19, 18] who offer alternative hypotheses.

2008

This paper looks at why the environmental aspect of the study of migration and refugees has been neglected. It proposes a definition of population movements induced by environmental factors, before concentrating on climate aspects by providing a synthesis of ...

Urban environment and climate change, 2018

Background/aim Climate change can both directly and indirectly drive human migration. Despite this, strong understanding of the system of determinants of migration and their interactions, remains a knowledge gap resulting in large uncertainties and ill-informed interventions. Objectives To create a new conceptual model for the identification of drivers of migration in the context of climate change. Methods A critical analysis of existing theoretical and quantitative literature was performed in order to synthesise a new conceptual model for identifying the migration determinants system. Results Quantitative studies fail to homogenously apply a theoretical model for the drivers of migration and the variety of migration outcomes that occur. This in turn results in a poor evidence-base for interventions in areas where this is critical, including public health, land planning and immigration policies. Existing theoretical models are insufficiently transferable and fail to capture the full range of migration determinants. A new migration typology and conceptual model of migration is constructed based on an upstream, holistic approach to migration. The model overcomes current shortcomings by capturing temporality and driver dynamics as well as being a plastic model that may be transferred into any context. Conclusion From the homogenous application of such a conceptual framework, quantitative models may also be able to more accurately quantify the extent to which contemporary and future climate change influences migration. Such models are therefore informative tools for decision-making concerning strategies for migration policy and public health planning.

Environment, Development and Sustainability

Climate change impacts on populations have increased the number of affected people and climate migrants worldwide. Although the nexus between climate change and migration is not monolithic, analyses of individual-level factors at the local scale that reveal the specific drivers of migration are lacking. Here, we show that people are motivated by individual calculations, prioritizing economic and social factors when deciding to migrate. We use data from 53 structured interviews to decompose the assessment of the decision-making process of people deciding to migrate from a region highly vulnerable to climate change, assessing the internal and external migratory potential. The assessment of migration potential evidenced that potential migrants react and make decisions based on perceptions and preferences among economic, social, environmental, and cultural factors when migrating and value these factors differently. Our spatial multi-criteria model reports disaggregation in that people p...

How are the populations of the world likely to shift? Which countries will be impacted by sea-level rise? This paper uses a country-level agent-based dynamic network model to examine shifts in population given network relations among countries, which influences overall population change. Some of the networks considered include: alliance networks, shared language networks, economic influence networks, and proximity networks. Validation of model is done for migration probabilities between countries, as well as for country populations and distributions. The proposed framework provides a way to explore the interaction between climate change and policy factors at a global scale. 1 INTRODUCTION Human migration is an important research topic, with major economic effects (OECD 2014). At the same time, the decision to migrate is also determined by economic factors (Pew Research Center 2013). This intertwining effect is best captured by agent-based models, where agents interact with their environment, and changes in the environment affects the decisions of agents. Previous studies on human migration generally make simplistic assumptions about the decision model of migration, or do not consider fluctuations in birth/death rates, age distributions as well as networks ties between countries. With recent economic trends (Grant, Mark 2016), birth policy changes (Buckley, Chris 2015) and climate trends in mind, it is important to develop an agent-based model that is sensitive to these changes. In this work, we developed a country-level agent-based model which aims to mimic the agent's decision-making process for migration. This is done through consideration of a range of country networks, ranging from alliances to linguistic similarities to climate and migrant networks, just to name a few. Additionally, we initialize the age distributions of countries according to actual data (US Census Bureau 2016). The age distribution is then shifted throughout the simulation through an aging process, as well as actual births and deaths in population. We then validate our model against data for migration probabilities, and country-level observations (population and age distributions). The results are promising, as we illustrate through performance measures such as average of prediction error.

International Journal of Environmental Research and Public Health, 2020

Both climate change and migration present key concerns for global health progress. Despite this, a transparent method for identifying and understanding the relationship between climate change, migration and other contextual factors remains a knowledge gap. Existing conceptual models are useful in understanding the complexities of climate migration, but provide varying degrees of applicability to quantitative studies, resulting in non-homogenous transferability of knowledge in this important area. This paper attempts to provide a critical review of climate migration literature, as well as presenting a new conceptual model for the identification of the drivers of migration in the context of climate change. It focuses on the interactions and the dynamics of drivers over time, space and society. Through systematic, pan-disciplinary and homogenous application of theory to different geographical contexts, we aim to improve understanding of the impacts of climate change on migration. A bri...

Climatic Change, 2006

This article presents a conceptual model to investigate population migration as a possible adaptive response to risks associated with climate change. The model reflects established theories of human migration behaviour, and is based upon the concepts of vulnerability, exposure to risk and adaptive capacity, as developed in the climate change research community. The application of the model is illustrated using the case of 1930s migration patterns in rural Eastern Oklahoma, which took place during a period of repeated crop failures due to drought and flooding.

With climate change a scientific fact, the possibility of international migration being affected by extreme weather events becomes increasingly likely. As weather events become more prevalent and violent, the amount of people who will seek shelter abroad will potentially increase. Indeed, there are many reasons for why people migrate and they are not always explicit and immediately apparent. The argument of this paper is that climate change has a significant impact on international migration.

2011

SN Social Sciences

There is limited attention on climate change (CC) and human migration among scholars and policymakers. Meanwhile, natural disasters are projected to induce migration in the coming years which will affect millions of people in sub-Saharan Africa (SSA). In this review, we contribute to climate migration literature by highlighting three important factors (i.e. floods, droughts, and sea-level rise) that predispose migrants in SSA to migrate. The review suggests that the environmental impact of CC in SSA cannot be overlooked. For example, the review discovered that the impact of flooding has intensified, and its impact on agriculture will affect rural–urban migration, forcing farmers to look for alternative job opportunities. Moreover, due to the lack of rainfall to support agricultural activities, the option of migrating away from agriculture and settling in urban areas becomes a possible coping strategy. Rising sea level will adversely affect many, due to a lack of adaptive capacity an...

Although it is widely recognized that climate change constitutes one of the main factor triggering migration, to date migration policies do still neglect this aspect leaving unprotected the environmental migrants, who are not even assisted by Refugee and Human Rights Laws. An analysis of these legal instruments can show the breaches regarding environmental migrants as well as a lack of political will to defend their rights. Such a stalemate could be overcome through the formalization of migration as adaptation to climate change. Migrating from a place to another in order to adapt to environmental transformations, is in fact a strategy that reduces the vulnerabilities, defends the needs and rectifies the status of environmental migrants. Nonetheless, its application on the ground can be ensured only if integrated in national and international migration planning frameworks that combine both bottom-up and top-down approaches, consider migrants as proactive actors shaping migration movements and policies, and recognize migration as an essential component of human development.