Environmental stress and agricultural landownership in Africa

We examine how weather variability affects agricultural landownership rates in Africa, where at least half of the population depends on agriculture to earn a livelihood. In the absence of effective adaptation strategies, households that experience difficulties farming due to environmental stress might leave their land. With implications for demography – through migration – and political instability – when affected populations express grievances – changing landownership patterns could make existing development challenges on the continent even more difficult. We test our hypothesis that drier than average growing seasons will reduce landownership rates using Demographic and Health Surveys (DHS). Our DHS dataset includes interviews with 850,961 households in 35 African countries between 2005 and 2017. Compared to regions experiencing weather near the historical average, those with five consecutive dry growing seasons before the DHS experienced a 6.93% decline in the landownership rate. For every additional dry growing season during the five years before each survey, the landownership rate fell by 1.38%. A host of robustness checks support our general conclusion that drying conditions are associated with lower landownership rates.     

Linking climate change and health outcomes: Examining the relationship between temperature,precipitation and birth weight in Africa

This paper examined the relationship between birth weight, precipitation, and temperature in 19 African countries. We matched recorded birth weights from Demographic and Health Surveys covering 1986 through 2010 with gridded monthly precipitation and temperature data derived from satellite and ground-based weather stations. Observed weather patterns during various stages of pregnancy were also used to examine the effect of temperature and precipitation on birth weight outcomes. In our empirical model we allowed the effect of weather factors to vary by the dominant food production strategy (livelihood zone) in a given region as well as by household wealth, mother's education and birth season. This allowed us to determine if certain populations are more or less vulnerable to unexpected weather changes after adjusting for known covariates. Finally we measured effect size by observing differences in birth weight outcomes in women who have one low birth weight experience and at least one healthy birth weight baby. The results indicated that climate does indeed impact birth weight and at a level comparable, in some cases, to the impact of increasing women's education or household electricity status.     

Climatic variability and changing reproductive goals in Sub-Saharan Africa

Using 40 rounds of Demographic and Health Survey data from 18 sub-Saharan African countries, linked to high-resolution historical climate records, we analyze the relationship between climatic variability and fertility goals among reproductive-aged women. We find that, overall, women exposed to above-average temperatures report lower ideal family size and reduced probability of desiring a first or additional child. Results indicate that exposure to precipitation anomalies during the 12 months prior to the DHS survey is associated with a significant reduction in ideal family size, but longer 60-month spells of above-average precipitation are associated with increases in ideal family size. Effects of unusual precipitation are null for women’s fertility preferences at both shorter- and longer-term periods. Additional analyses show that this association varies across sub-populations defined by parity, education, residence in rural or urban areas, and region. In general, our results suggest that women exposed to adverse environmental conditions—namely abnormally hot or dry spells—will reduce their ideal family size and their preferences for having another child. In some cases, however, fertility goals may also decline during spells of favorable environmental conditions, possibly due to increased labor demands among women and their spouses. One implication of the observed links between climate variability and reproductive goals is that policymakers concerned with climate adaptation should work to ensure women have access to the necessary family planning resources needed to realize dynamic reproductive goals in a changing climate.     

Challenging climate change and migration discourse: Different understandings of timescale and temporality in the Maldives

This article draws on ongoing research in the Maldives to explore differences between elite and non-elite perceptions of climate change and migration. It argues that, in addition to variations in perceptions based on diverse knowledge, priorities and agendas, there exists a more fundamental divergence based upon different understandings of the timescale of climate change and related ideas of urgency and crisis. Specifically, elites tend to focus on a distant future, which is generally abstracted from people's everyday lived realities, and to utilise the language of a climate change-induced migration ‘crisis’ in their discussions about impacts in a manner not envisaged by non-elites. The article concludes that, rather than unproblematically mapping global, external facing narratives wholesale onto ordinary people's lives and experiences, there needs to be more dialogue between elites and non-elites on climate change and migration issues. These perspectives should be integrated more effectively into the development of policy interventions designed to support people in adapting to the impacts of global environmental change.     

春季欧亚-北太平洋上空大气质量迁移规律及其对中国同期气候异常的可能影响

利用1979～2013年NCEP/NCAR月平均再分析资料及NOAA研究中心的CMAP（CPC Merged Analysis of Precipitation）月平均降水资料,通过定义欧亚—北太平洋间大气质量迁移指数I_MAMEP,分析了春季欧亚—北太平洋上空大气质量迁移（MAMEP,Migration of Atmospheric Mass over Regions between Eurasia and North Pacific）的年际变化规律及其与同期中国气候异常的联系。结果表明:在北半球中高纬度存在一个纬向分布的欧亚—北太平洋遥相关型,且其可能对中国同期气候异常的形成具有重要影响。春季MAMEP指数具有显著的长期趋势,同时还具有2～4年及5～7年的振荡周期及明显的年代际变化特征。垂直环流和波动运动对欧亚—北太平洋间大气质量迁移具有重要作用。大气质量在欧亚西部低层异常辐合,高层异常辐散,在中、西太平洋地区低层异常辐散,高层异常辐合,在纬向上构成了顺时针的垂直环流圈,将西北太平洋地区的大气质量变动与欧亚大陆上空的变动联系了起来。另外,来自西欧大陆的波扰能量可传播至北太平洋,有利于这些区域上空位势高度异常扰动的维持。I_MAMEP与春季同期降水及地表气温异常关系密切。I_MAMEP为正时,东亚以北地区、鄂霍次克海西岸以及西欧沿岸降水显著减少,欧亚西部及我国华北地区降水显著增加。850 hPa上西伯利亚受反气旋式环流控制,太平洋上空受气旋式环流控制,引起欧亚大陆北部地表显著增温,西伯利亚以东、我国东北、华北—江淮地区及韩国、日本南部地表显著降温。西欧—我国西北部分地区大面积显著降温现象与这两个地区受异常反气旋东侧的偏北气流影响有关。这些结果有利于人们更深刻认识区域春季气候异常形成机理。     

The streetlight effect in climate change research on Africa

The streetlight effect is the tendency for researchers to focus on particular questions, cases and variables for reasons of convenience or data availability rather than broader relevance, policy import, or construct validity. To what extent does the streetlight effect condition the state of knowledge about climate change in Africa? Analysis of Google Scholar search results, both general and within leading climate change-related journals, reveals that two proxies for objective need, population and land mass, are associated with a higher volume of scholarly attention. Countries with greater exposure to the negative effects of climate change and countries with less adaptive capacity do not receive more scholarly attention. Rather, I find evidence that factors like British colonial history, strong civil liberties, and to a lesser extent political stability − factors not directly related to risks from climate change − affect scholarly attention. The streetlight effect is evident in climate change research on Africa.     

Competing discourses of energy development: The implications of the Medupi coal-fired power plant in South Africa

This study explores the discursive dynamics behind the controversy to build the US$17.8 billion 4800 MW Medupi coal-fired power plant in South Africa, the seventh largest in the world. It begins by viewing climate change and energy security not as objective fact driven concepts, but constantly negotiated discourses. Based on a sampling of project documents, reports, testimony, and popular articles, the study then maps the discursive justifications behind the project as well as those against it. More specifically, it isolates themes of economic development, environmental sustainability, and energy security that converge into a discursive ensemble of inevitability supporting complete electrification for all of South Africa. The study also documents themes at the heart of the campaign against Medupi: maldevelopment and secrecy, local and global environmental degradation, and energy poverty which coalesce into a grand narrative of democracy. Tracing the intricacies of the Medupi controversy provides rich insight into energy policy and planning in South Africa. It also emphasizes how struggles to expand access to energy services can exacerbate degradation of the environment, and shows how climate and environmental discourses can become institutionalized.     

Measuring the environmental dimensions of human migration: The demographer's toolkit

In recent years, the empirical literature linking environmental factors and human migration has grown rapidly and gained increasing visibility among scholars and the policy community. Still, this body of research uses a wide range of methodological approaches for assessing environment–migration relationships. Without comparable data and measures across a range of contexts, it is impossible to make generalizations that would facilitate the development of future migration scenarios. Demographic researchers have a large methodological toolkit for measuring migration as well as modeling its drivers. This toolkit includes population censuses, household surveys, survival analysis and multi-level modeling. This paper's purpose is to introduce climate change researchers to demographic data and methods and to review exemplary studies of the environmental dimensions of human migration. Our intention is to foster interdisciplinary understanding and scholarship, and to promote high quality research on environment and migration that will lead toward broader knowledge of this association.     

Understanding the relationship between environmental change and migration: The development of an effects framework based on the case of northern Ethiopia

Empirical work on the relationship between environmental stress and human migration has blossomed over the last 10 years. While such work has provided important insights into this relationship, there has been, to date, limited effort expended on generating a generalisable framework for apprehending such interactions. This paper seeks to address this deficit. Based on semi-structured interviews in two sending and four receiving areas in northern Ethiopia, it explores dominant mobility narratives among populations whose livelihoods are exposed to a range of environmental stresses. Analysis of these narratives corroborates findings from other empirical studies on the subject, highlighting how the impact of environmental stress on human mobility can only be understood within the context in which it occurs. To this end the paper attempts to generate a typology of interactions between environmental and non-environmental factors shaping mobility. The typology is based on four effects: additive, enabling, vulnerability and barrier effects. It is thought to provide a generalisable conceptual language which is capable of describing the role of environmental stress in mobility decisions and thereby offering a systematic means for thinking through the processes by which environmental stress impacts upon mobility. While the framework is hypothesised to be suitably generalisable to account for other contexts and other environmental stresses, this still needs to be tested. In addition it is acknowledged that the framework suffers from some major limitations. Most notable is reliance on a conceptually false distinction between environmental and non-environmental factors, and the inability to account for the non-environmental features which shape perceptions of migration.     

Climate variability and child nutrition: Findings from sub-Saharan Africa

Climatic variability affects many underlying determinants of child malnutrition, including food availability, access, and utilization. Evidence of the effects of changing temperatures and precipitation on children’s nutritional status nonetheless remains limited. Research addressing this knowledge gap is merited given the short- and long-run consequences of malnutrition. We address this issue by estimating the effects of temperature and precipitation anomalies on the weight and wasting status of children ages 0–59 months across 18 countries in sub-Saharan Africa. Linear regression models show that high temperatures and low precipitation are associated with reductions in child weight, and that high temperatures also lead to increased risk of wasting. We find little evidence of substantively meaningful differences in these effects across sub-populations of interest. Our results underscore the vulnerability of young children to climatic variability and its second-order economic and epidemiological effects. The study also highlights the corresponding need to design and assess interventions to effectively mitigate these impacts.     

The future urban heat-wave challenge in Africa: Exploratory analysis

Urbanization and climate change are among the most important global trends affecting human well-being during the twenty-first century. One region expected to undergo enormous urbanization and be significantly affected by climate change is Africa. Studies already find increases in temperature and high temperature events for the region. How many people will be exposed to heat events in the future remains unclear. This paper attempts to provide a first estimate of the number of African urban residents exposed to very warm 15-day heat events (>42 °C). Using the Shared Socio-economic Pathways and Representative Concentration Pathways framework we estimate the numbers of exposed, sensitive (those younger than 5 and older than 64 years), and those in low-income nations, with gross national products of $4000 ($2005, purchasing power parity), from 2010 to 2100. We examine heat events both with and without urban heat island estimates. Our results suggest that at the low end of the range, under pathways defined as sustainable (SSP 1) and low relative levels of climate change (RCP 2.6) without including the urban heat island effect there will be large populations (>300 million) exposed to very warm heat wave by 2100. Alternatively, by 2100, the high end exposure level is approximately 2.0 billion for SSP 4 under RCP 4.5 where the urban heat island effect is included.     

Unveiling hidden migration and mobility patterns in climate stressed regions: A longitudinal study of six million anonymous mobile phone users in Bangladesh

Climate change is likely to drive migration from environmentally stressed areas. However quantifying short and long-term movements across large areas is challenging due to difficulties in the collection of highly spatially and temporally resolved human mobility data. In this study we use two datasets of individual mobility trajectories from six million de-identified mobile phone users in Bangladesh over three months and two years respectively. Using data collected during Cyclone Mahasen, which struck Bangladesh in May 2013, we show first how analyses based on mobile network data can describe important short-term features (hours–weeks) of human mobility during and after extreme weather events, which are extremely hard to quantify using standard survey based research. We then demonstrate how mobile data for the first time allow us to study the relationship between fundamental parameters of migration patterns on a national scale. We concurrently quantify incidence, direction, duration and seasonality of migration episodes in Bangladesh. While we show that changes in the incidence of migration episodes are highly correlated with changes in the duration of migration episodes, the correlation between in- and out-migration between areas is unexpectedly weak. The methodological framework described here provides an important addition to current methods in studies of human migration and climate change.     

Agriculture,irrigation and drought induced international migration: Evidence from Mexico

There is now substantial empirical evidence that climatic variability increases international migration, but relatively little is known about the mechanism driving the association and about adaptations that may reduce it. We use detailed data on migrants from Mexico to the U.S. to provide evidence in support of the hypothesis that drought induced migration from Mexico to the U.S. is mediated by agricultural income shocks. Migration rates increase in drought years, but only in Mexico’s drier regions, and the response is stronger in states and seasons in which agricultural production is also more sensitive to precipitation. Moreover, among the sample, only farmers display a significant increase in migration rates in drought years, and the effect is substantially weaker for households with access to irrigation.     

Carbon sequestration in Africa: The land tenure problem

The prospect of using tropical forest projects to sequester significant amounts of atmospheric carbon as one mitigation approach to climate change has received considerable attention. In the Kyoto Protocol, the Clean Development Mechanism (CDM) aspires to make such projects viable. This article examines the prospect of these projects in Africa, and argues that land tenure is much more than just a set of variables to be changed, and that instead it exists as a prohibitive obstacle to the implementation of afforestation and reforestation sequestration approaches. Five primary tenure problems are examined: (1) the disconnect between customary and statutory land rights, (2) legal pluralism, (3) tree planting as land claim, (4) expansion of treed areas in smallholder land use systems, and (5) the difficulty of using the ‘abandoned land’ category. The pervasiveness of these tenurial issues mean that the prospects for successfully implementing afforestation and reforestation projects in Africa are in reality quite weak. The current project approach to carbon storage in Africa needs to be significantly realigned with African reality in order for sequestration expectations to be practical.     

Adaptation to climate change in Africa: Challenges and opportunities identified from Ethiopia

Africa is widely held to be highly vulnerable to future climate change and Ethiopia is often cited as one of the most extreme examples. With this in mind we seek to identify entry points to integrate short- to medium-term climate risk reduction within development activities in Africa, drawing from experiences in Ethiopia. To achieve this we employ a range of data and methods. We examine the changing nature of climate risks using analysis of recent climate variability, future climate scenarios and their secondary impacts. We assess the effects of climate variability on agricultural production and national GDP. Entry points and knowledge gaps in relation to mainstreaming climate risks in Ethiopia are identified using the Government's plan for poverty reduction. We end with a case study incorporating climate risks through drought insurance within the current social protection programme in Ethiopia, which provides support to 8.3 million people.Rainfall behaviour in Ethiopia shows no marked emergent changes and future climate projections show continued warming but very mixed patterns of rainfall change. Economic analysis highlights sensitivities within the economy to large-scale drought, however, while the effects are clear in major drought years in other years the relationship is weak. For social protection fairly small positive and negative effects on the number of recipients and frequency of cash payments during drought occur under the extreme range of climate model rainfall projections (2020s).Our analysis highlights several important challenges and opportunities for addressing climate risks. Challenges primarily relate to the large uncertainties in climate projections for parts of Africa, a weak evidence base of complex, often non-deterministic, climate-society interactions and institutional issues. Opportunities relate to the potential for low-regrets measures to reduce vulnerability to current climate variability which can be integrated with relatively modest effort within a shift in Africa from a disaster-focused view of climate to a long-term perspective that emphasises livelihood security and vulnerability reduction.     

西太平洋海温和南方涛动与中国冬季气候异常关系年代际变化的对比分析

利用NCEP/NCAR再分析资料和全球海温海冰GISST2.3b资料、英国CRU提供的南方涛动指数以及中国160站月平均降水和气温资料, 分析了冬季西太平洋海温和南方涛动与中国冬季气候异常关系年代际变化特征。结果表明:最近50年, 西太平洋海温指数 (WPI) 与南方涛动指数 (SOI) 之间相关关系的年代际变化在冬季很明显。当WPI-SOI相关关系不显著时, 在西太平洋赤道北侧的对流层低层存在高 (低) 海温-反气旋 (气旋) 异常环流系统, 不利于维持ENSO与西太平洋海温变化间的紧密联系; 与此相对应, 冬季整个对流层环流呈相当正压结构。在WPI-SOI相关显著 (不显著) 时段, 冬季中国降水、气温与西太平洋海温之间的相关较弱 (较强)。     

The devil is in the details: An investigation of the relationships between conflict,food price and climate across Africa

This study investigates the relationship between violent conflict, food price, and climate variability at the subnational level. Using disaggregated data on 113 African markets from January 1997 to April 2010, interrelationships between the three variables are analyzed in simultaneous equation models. We find that: (i) a positive feedback exists between food price and violence – higher food prices increase conflict rates within markets and conflict increases food prices; (ii) anomalously dry conditions are associated with increased frequencies of conflict; and (iii) decreased rainfall exerts an indirect effect on conflict through its impact on food prices. These findings suggest that the negative effects of climate variability on conflict can be mitigated by interventions and effective price management in local markets. Creating environments in which food prices are stable and reliable, and markets are accessible and safe, can lower the impacts of both climate change and conflict feedbacks.     

夏季厄尔尼诺-Modoki和东部型ENSO海表温度异常分布型特征及其与海洋性大陆区域气候异常的联系

2007年,Ashok等揭示了赤道太平洋区域存在一种三极型分布海表温度异常并称之为厄尔尼诺-Modoki,同时定义了相应的海表温度异常指数EMI（记为I_EM）。在此基础上,利用英国哈得来中心逐月海表温度资料、美国NCEP/NCAR月平均再分析数据集、美国国家海洋和大气管理局（NOAA）逐月降水资料（CMAP）,通过在太平洋海表温度异常中扣除厄尔尼诺-Modoki信号后,在Nino1+2区域上定义了东太平洋型海表温度异常指数EPNI（I_EPN）。据此,由I_EPN和I_EM可构成描述热带太平洋海表温度异常变化的一对指数。分析了两个指数相应的海气状态及对海洋性大陆区域气候异常的影响。结果表明,厄尔尼诺-Modoki和东太平洋型海表温度异常及其影响存在显著差异。在北半球夏季,当I_EM处于正位相时,热带太平洋海表温度异常呈现“负-正-负”的结构,海洋性大陆大部分区域海表温度异常为负,此时对流层低层太平洋地区辐合,海洋性大陆地区辐散,对流层高层太平洋地区辐散,海洋性大陆地区辐合。对应于辐合辐散中心,存在着自赤道中太平洋分别向赤道东太平洋和海洋性大陆中东部地区的异常垂直环流圈,同时也存在自海洋性大陆西部向印度洋西部的垂直环流。大气在海洋性大陆区域北部加热,南部冷却;在太平洋地区西部加热而东部冷却;在海洋性大陆区域10°N以南降水偏少,而10°N以北降水偏多。当I_EPN处于正位相时,热带太平洋海表温度异常呈现“西负东正”分布型,海洋性大陆区域海表温度异常呈现“西正东负”分布,对流层低层海洋性大陆地区辐散中心范围偏大、位置偏东、强度偏强,太平洋地区辐合中心范围偏小、位置偏东,热带环流异常在垂直方向上呈斜压结构,海洋性大陆区域北部大气加热而南部冷却,太平洋地区大气均呈加热正异常,海洋性大陆大部分区域降水均偏少,赤道太平洋降水偏多。以上这些结果有利于深刻理解热带太平洋海表温度异常的特征及其对海洋性大陆区域气候的影响。     

夏季厄尔尼诺-Modoki和东部型ENSO海表温度异常分布型特征及其与海洋性大陆区域气候异常的联系

2007年,Ashok等揭示了赤道太平洋区域存在一种三极型分布海表温度异常并称之为厄尔尼诺-Modoki,同时定义了相应的海表温度异常指数EMI（记为I_EM）。在此基础上,利用英国哈得来中心逐月海表温度资料、美国NCEP/NCAR月平均再分析数据集、美国国家海洋和大气管理局（NOAA）逐月降水资料（CMAP）,通过在太平洋海表温度异常中扣除厄尔尼诺-Modoki信号后,在Nino1+2区域上定义了东太平洋型海表温度异常指数EPNI（I_EPN）。据此,由I_EPN和I_EM可构成描述热带太平洋海表温度异常变化的一对指数。分析了两个指数相应的海气状态及对海洋性大陆区域气候异常的影响。结果表明,厄尔尼诺-Modoki和东太平洋型海表温度异常及其影响存在显著差异。在北半球夏季,当I_EM处于正位相时,热带太平洋海表温度异常呈现“负-正-负”的结构,海洋性大陆大部分区域海表温度异常为负,此时对流层低层太平洋地区辐合,海洋性大陆地区辐散,对流层高层太平洋地区辐散,海洋性大陆地区辐合。对应于辐合辐散中心,存在着自赤道中太平洋分别向赤道东太平洋和海洋性大陆中东部地区的异常垂直环流圈,同时也存在自海洋性大陆西部向印度洋西部的垂直环流。大气在海洋性大陆区域北部加热,南部冷却;在太平洋地区西部加热而东部冷却;在海洋性大陆区域10°N以南降水偏少,而10°N以北降水偏多。当I_EPN处于正位相时,热带太平洋海表温度异常呈现“西负东正”分布型,海洋性大陆区域海表温度异常呈现“西正东负”分布,对流层低层海洋性大陆地区辐散中心范围偏大、位置偏东、强度偏强,太平洋地区辐合中心范围偏小、位置偏东,热带环流异常在垂直方向上呈斜压结构,海洋性大陆区域北部大气加热而南部冷却,太平洋地区大气均呈加热正异常,海洋性大陆大部分区域降水均偏少,赤道太平洋降水偏多。以上这些结果有利于深刻理解热带太平洋海表温度异常的特征及其对海洋性大陆区域气候的影响。      

Soil quality and human migration in Kenya and Uganda

Soil degradation is widely considered to be a key factor undermining agricultural livelihoods in the developing world and contributing to rural out-migration. To date, however, few quantitative studies have examined the effects of soil characteristics on human migration or other social outcomes for potentially vulnerable households. This study takes advantage of a unique longitudinal survey dataset from Kenya and Uganda containing information on household-level soil properties to investigate the effects of soil quality on population mobility. Random effects multinomial logit models are used to test for effects of soil quality on both temporary and permanent migration while accounting for a variety of potential confounders. The analysis reveals that soil quality significantly reduces migration in Kenya, particularly for temporary labor migration, but marginally increases migration in Uganda. These findings are consistent with several previous studies in showing that adverse environmental conditions tend to increase migration but not universally, contrary to common assumptions about environmentally-induced migration.