A machine learning analysis of drought and rural population change on the North American Great Plains since the 1970s

Population and Environment - Machine learning techniques have to date not been widely used in population-environment research, but represent a promising tool for identifying relationships between...     

Soil and its influence on rural drought migration: insights from Depression-era Southwestern Saskatchewan, Canada

This article investigates linkages between soil conditions, farm-level vulnerability, adaptation, and rural migration during periods of drought. It begins by reviewing existing literature on climate adaptation in agricultural populations and on relationships between soil and rural migration. This is followed by a detailed case study of rural migration patterns that emerged in the Swift Current district of Saskatchewan, Canada, during a period of extended droughts and severe economic conditions in the 1930s. Using a combination of secondary literature, interviews with surviving first-hand observers and GIS modeling, the study shows how the interacting effects of household indebtedness, social capital, government relief programs, and farm-level soil quality helped stimulate population loss in many rural townships across the study area. The study focuses particularly on the role played by differential soil quality across the Swift Current district and how farms situated on sandier soils were typically more sensitive and vulnerable to drought than those situated on clay soils. Higher-than-average rates of population loss were associated with townships containing areas of poorer quality agricultural soils, an association replicable using GIS software and existing soil and population datasets. The findings from the case study are discussed within the context of the broader existing literature, and suggestions are provided on future directions for research, planning, and modeling to assist planners and policymakers concerned with rural adaptation and migration.     

What we learned from the Dust Bowl: lessons in science,policy, and adaptation

This article provides a review and synthesis of scholarly knowledge of Depression-era droughts on the North American Great Plains, a time and place known colloquially as the Dust Bowl era or the Dirty Thirties. Recent events, including the 2008 financial crisis, severe droughts in the US corn belt, and the release of a popular documentary film, have spawned a resurgence in public interest in the Dust Bowl. Events of the Dust Bowl era have also proven in recent years to be of considerable interest to scholars researching phenomena related to global environmental change, including atmospheric circulation, drought modeling, land management, institutional behavior, adaptation processes, and human migration. In this review, we draw out common themes in terms of not only what natural and social scientists have learned about the Dust Bowl era itself, but also how insights gained from the study of that period are helping to enhance our understanding of climate–human relations more generally.     

Household access to capital and its effects on drought adaptation and migration: a case study of rural Alberta in the 1930s

This article reports findings from an empirical study of the impacts of drought on rural households in southeastern Alberta, Canada during the 1930s. In that decade, extreme summer heat conditions and low precipitation levels led to repeated crop failures. These extreme climatic conditions coincided with economic recession, falling commodity prices, and rising unemployment to create widespread hardship and suffering across the rural population. Thousands of households adapted by leaving the drought-stricken region and migrating to more northerly regions unaffected by drought, often suffering still further hardship as they reestablished themselves in a new environment. Through secondary research of historical documents and interviews with surviving migrants and non-migrants, this study identifies how economic, human, and social capital influenced the adaptive capacity, adaptation decisions, and migration behavior of rural households and describes how institutional responses affected household adaptation. Differential access to capital in its various forms was a key factor that distinguished households that adapted via migration from those that did not. The findings from this study of historical environment-related population change provide insights that enhance our broader understanding of potential future migration responses to the impacts of anthropogenic climate change and important considerations for policy-makers and planners seeking to build adaptive capacity in rural populations.     

Empirical research on international environmental migration: a systematic review

This paper presents the findings of a systematic review of scholarly publications that report empirical findings from studies of environmentally-related international migration. There exists a small, but growing accumulation of empirical studies that consider environmentally-linked migration that spans international borders. These studies provide useful evidence for scholars and policymakers in understanding how environmental factors interact with political, economic and social factors to influence migration behavior and outcomes that are specific to international movements of people, in highlighting promising future research directions, and in raising important considerations for international policymaking. Our review identifies countries of migrant origin and destination that have so far been the subject of empirical research, the environmental factors believed to have influenced these migrations, the interactions of environmental and non-environmental factors as well as the role of context in influencing migration behavior, and the types of methods used by researchers. In reporting our findings, we identify the strengths and challenges associated with the main empirical approaches, highlight significant gaps and future opportunities for empirical work, and contribute to advancing understanding of environmental influences on international migration more generally. Specifically, we propose an exploratory framework to take into account the role of context in shaping environmental migration across borders, including the dynamic and complex interactions between environmental and non-environmental factors at a range of scales.     

Thresholds in climate migration

Migration in response to climatic hazards or changes in climatic conditions can unfold in a variety of ways, ranging from barely observable, incremental changes in pre-existing migration flows to abrupt, non-linear population movements. The adoption of migration instead of in situ adaptation responses, and the high degree of variability in potential migration outcomes, in part reflects the presence of thresholds or tipping points within the processes of human-environment interaction through which climate adaptation and migration take place. This article reviews and makes linkages between existing research in climate adaptation, migration system dynamics, residential preferences, and risk perception to identify and explore the functioning and importance of thresholds. Parochial examples from the author’s published research on climate adaptation and migration in rural North America are used to illustrate. Six types of thresholds in response to climate hazards are identified: (1) Adaptation becomes necessary; (2) Adaptation becomes ineffective; (3) Substantive changes in land use/livelihoods become necessary; (4) In situ adaptation fails, migration ensues; (5) Migration rates become non-linear; and (6) Migration rates cease to be non-linear. Movement across thresholds is driven by context-specific characteristics of climate events, natural systems, and/or human systems. Transition from incremental to non-linear migration can be accelerated by people’s perceptions, by actions of influential individuals or groups, and by changes in key infrastructure, services, or other community assets. Non-linear climate migration events already occur at local and sub-regional scales. The potential for global scale, non-linear population movements later this century depends heavily on future greenhouse gas emission trends. The ability to identify and avoid thresholds that tip climate migration into a non-linear state will be of growing concern to policy makers and planners at all levels in coming decades. This article forms part of a special issue of this journal dedicated to the late Graeme Hugo, and the author draws heavily on past research by Professor Hugo and colleagues.     

Environmental influences on African migration to Canada: focus group findings from Ottawa-Gatineau

There is limited empirical evidence of how environmental conditions in the Global South may influence long-distance international migration to the Global North. This research note reports findings from seven focus groups held in Ottawa-Gatineau, Canada, with recent migrants from the Horn of Africa and francophone sub-Saharan Africa, where the role of environment in migration decision-making was discussed. Participants stated that those most affected by environmental challenges in their home countries lack the financial wherewithal to migrate to Canada. Participants also suggested that internal rural–urban migration patterns generated by environmental challenges in their home countries underlay socioeconomic factors that contributed to their own migration. In other words, environment is a second- or third-order contributor in a complex chain of interactions in the migrant source country that may lead to long-distance international migration by skilled and educated urbanites. These findings have informed the scope and detail of a larger, ongoing empirical study of environmental influences on immigration to Canada.     

Impacts of population change on vulnerability and the capacity to adapt to climate change and variability: a typology based on lessons from “a hard country”

This article describes and analyzes the impacts of population and demographic change on the vulnerability of communities to climate change and variability. It begins with a review of existing literature on the effects of population change on anthropogenic greenhouse gas emissions, the exposure of settlements to climate risks, and on the capacity to adapt to climate change. The article explores the relationship between population change and adaptive capacity through detailed examination of empirical findings from a study of small communities in eastern Ontario, Canada currently experiencing a combination of changes in local climatic conditions and rapid demographic change caused by in-migration of urban retirees and out-migration of young, educated people. The combination of changing demographic and climatic patterns has placed increased stress on local social networks that have long been critical to climate adaptation in that region. The case study and literature review are used to create a general typology of the relationship between population change and vulnerability that may be used as a framework for future research in this field.