Investigating the relationship between growing season quality and childbearing goals

Agricultural production and household food security are hypothesized to play a critical role connecting climate change to downstream effects on women’s health, especially in communities dependent on rainfed agriculture. Seasonal variability in agriculture strains food and income resources and makes it a challenging time for households to manage a pregnancy or afford a new child. Yet, there are few direct assessments of the role locally varying agricultural quality plays on women’s health, especially reproductive health. In this paper we build on and integrate ideas from past studies focused on climate change and growing season quality in low-income countries with those on reproductive health to examine how variation in local seasonal agricultural quality relates to childbearing goals and family planning use in three countries in sub-Saharan Africa: Burkina Faso, Kenya, and Uganda. We use rich, spatially referenced data from the Performance Monitoring for Action (PMA) individual surveys with detailed information on childbearing preferences and family planning decisions. Building on recent advances in remote monitoring of seasonal agriculture, we construct multiple vegetation measures capturing different dimensions of growing season conditions across varying time frames. Results for the Kenya sample indicate that if the recent growing season is better a woman is more likely to want a child in the future. In Uganda, when the growing season conditions are better, women prefer to shorten the time until their next birth and are also more likely to discontinue using family planning. Additional analyses reveal the importance of education and birth spacing in moderating these findings. Overall, our findings suggest that, in some settings, women strategically respond to growing season conditions by adjusting fertility aspirations or family planning use. This study also highlights the importance of operationalizing agriculture in nuanced ways that align with women’s lives to better understand how women are impacted by and respond to seasonal climate conditions.     

Disruption,not displacement: Environmental variability and temporary migration in Bangladesh

Mass migration is one of the most concerning potential outcomes of global climate change. Recent research into environmentally induced migration suggests that relationship is much more complicated than originally posited by the ‘environmental refugee’ hypothesis. Climate change is likely to increase migration in some cases and reduce it in others, and these movements will more often be temporary and short term than permanent and long term. However, few large-sample studies have examined the evolution of temporary migration under changing environmental conditions. To address this gap, we measure the extent to which temperature, precipitation, and flooding can predict temporary migration in Matlab, Bangladesh. Our analysis incorporates high-frequency demographic surveillance data, a discrete time event history approach, and a range of sociodemographic and contextual controls. This approach reveals that temporary migration declines immediately after flooding but quickly returns to normal. In contrast, high temperatures have sustained positive effects on temporary migration that persist over one to two year periods, while migrations decrease during extended periods of extreme precipitation. Building on previous studies of long-term migration, these results challenge the common assumption that flooding, precipitation extremes, and high temperatures will consistently increase temporary migration. Instead, our results are consistent with a livelihoods interpretation in which long-standing household livelihood strategies (both temporary migration and agriculture) are disrupted by environmental variability.     

Inequalities, institutions, and forest commons

This paper contributes to a growing literature on the commons that examines the relationship between inequality and commons outcomes. Our analysis of evidence on forest commons outcomes in 228 cases from South Asia (India and Nepal), East Africa (Kenya and Uganda) and Latin America (Mexico and Bolivia) suggests that local governance and collective action matter in shaping how socioeconomic inequalities affect forest conditions. In particular, we find that both inter-group and intra-group economic inequalities have consistently negative effects on forest outcomes, but that effectively functioning local institutions for collective action dampen the negative effect of inter-group inequality on forest outcomes.     

Implications of Country-Level Decisions on the Specification of Crown Cover in the Definition of Forests for Land Area Eligible for Afforestation and Reforestation Activities in the CDM

Within the Kyoto Protocol, countries have significant latitude to define a forest. The most important parameter affecting area designated as forest is the minimum crown density which can be set between 10 and 30 percent. The choice will have implications for the amount of land available in a country for afforestation and reforestation (A/R) activities within the Clean Development Mechanism (CDM). In this paper, we used GIS analysis to look at four case studies from countries involved in the EU-funded ENCOFOR project: Bolivia, Ecuador, Uganda and Kenya. We also looked at the effects of other factors that would exclude land from eligibility for A/R projects. A low threshold of 10 percent crown cover resulted in exclusion of 70 to 90 percent of the land area of all countries except Kenya, which differed from the other countries by its large dryland areas. Much less area was excluded when higher thresholds were used. The spatial analyses showed not only the effects of the choice of the crown cover criterion, but also where the land was available for CDM activities within each country at different thresholds. This is the first time that the effect of the crown cover element of the Kyoto forest definition on land availability and distribution for CDM A/R activities has been quantified. While there are a number of reasons to choose different thresholds, this analysis suggests that countries that are considering using CDM finance for rural development might want to select the higher minimum threshold for crown cover in order to maximize their participation and flexibility.     

Factors affecting whether environmental migration is temporary or permanent: Evidence from Bangladesh

This study examines whether environmental migrants in Bangladesh move permanently or temporarily. The analyses are based on data collected in 2010 and 2011, and cover four themes, namely migrant characteristics, environmental change related factors, conflict and adaptation strategies, and social networks. The estimates obtained from binary logit models show that most sets of variables have statistically significant impacts on the temporary migration versus permanent migration decision. Females are more inclined to migrate temporarily, a finding which is consistent with prior studies that argued that female migration is one temporary household survival strategy in the face of an environmental crisis. The probability of intending to move temporarily is significantly affected by the prior occupational experience: Migrants who were previously engaged in agriculture or fishing are more inclined to migrate permanently. Those households who reported that they had lost assets due to environmental hazards are shown to have a higher probability of becoming permanent migrants. In contrast, loss of livestock and crop failure are associated with a greater likelihood of temporary migration. The empirical results reveal the groups that can be targeted in destination regions in settlement policy, and equally the groups whose return home can be facilitated once any immediate danger has passed.     

Climate-Induced migration and unemployment in middle-income Africa

One of the major unresolved questions in the study of vulnerability to climate change is how human migration will respond in low and middle-income countries. The present study directly addresses this lacuna by using census data on migration from 4 million individuals from three middle-income African countries over a 22-year period. We link these individuals to climate exposures in their origins and estimate climatic effects on migration using a fixed-effects regression model. We show that climate anomalies affect mobility in all three countries. Specifically, mobility declines by 19% with a 1-standard deviation increase in temperature in Botswana. Equivalent changes in precipitation cause declines in migration in Botswana (11%) and Kenya (10%), and increases in migration in Zambia (24%). The mechanisms underlying these effects appear to differ by country. Negative associations between precipitation anomalies, unemployment, and inactivity suggest migration declines may be due to an increased local demand for workers to offset production risk, while migration increases may be indicative of new opportunities in destinations. These country-specific findings highlight the contextually-specific nature of climate-migration relationships, and do not support claims that climate change is widely contributing to urbanization across Africa.     

沙尘暴研究中的若干科学问题

近年来,中国北方频繁发生的沙尘暴事件引起世人的关注.实际上,沙尘暴不仅影响空气质量、交通,造成土壤风蚀和其他人、畜生命财产等社会、经济损失,作为一种特殊类型的大气气溶胶,沙尘粒子还具有重要的气候和环境效应.作者在简单综述沙尘暴研究的基础上,将重点探讨沙尘暴研究中一些值得注意的科学问题.     

Satellite-based rainfall data reveal a recent drying trend in central equatorial Africa

West-central Uganda, a biodiversity hotspot on the eastern edge of central equatorial Africa (CEA), is a region coping with balancing food security needs of a rapidly growing human population dependent on subsistence agriculture with the conservation of critically endangered species. Documenting and understanding rainfall trends is thus of critical importance in west-central Uganda, but sparse information exists on rainfall trends in CEA during the past several decades. The recently created African Rainfall Climatology version 2 (ARC2) dataset has been shown to perform satisfactorily at identifying rainfall days and estimating seasonal rainfall totals in west-central Uganda. Therefore, we use ARC2 data to assess rainfall trends in west-central Uganda and other parts of equatorial Africa from 1983–2012. The core variables examined were three-month rainfall variables for west-central Uganda, and annual rainfall variables and seasonal rainfall totals for a transect that extended from northwestern Democratic Republic of the Congo to southern Somalia. Significant decreases in rainfall in west-central Uganda occurred for multiple three-month periods centered on boreal summer, and rainfall associated with the two growing seasons decreased by 20 % from 1983–2012. The drying trend in west-central Uganda extended westward into the Congo rainforest. Rainfall in CEA was significantly correlated with the Atlantic Multidecadal Oscillation (AMO) at the annual scale and during boreal summer and autumn. Two other possible causes of the decreasing rainfall in CEA besides North Atlantic Ocean sea-surface temperatures (e.g., AMO), are the warming of the Indian Ocean and increasing concentrations of carbonaceous aerosols over tropical Africa from biomass burning.     

陆面过程模式中地下水位的参数化及初步应用

田间研究表明地表水和地下水有重要的相互作用,它与土壤含水量密切相关.土壤含水量不仅在陆气相互作用系统水和能量平衡中,而且在干旱、洪水预报、水资源管理、生态系统研究中起十分重要的作用.因此,研究地表水和地下水的相互作用,建立陆面模式中地下水位的动态表示,对于气候与水资源研究具有重要意义.将地下水位的动态表示问题归结为饱和与非饱和流问题,发展了其数值计算方案,建立了地下水位的动态表示,并与陆面过程模型耦合,建立了陆气相互作用中地下水位的动态表示,并进行了数值模拟研究.     

Women's participation in forest management: A cross-country analysis

The role of women's participation in community forestry has recently been investigated in a number of theoretical and empirical papers. This paper takes an existing theoretical framework developed by Agarwal (2001) and applies it to examine two questions: (1) What determines women's participation in forestry institutions? and (2) What effect does women's participation have on institutional outcomes (such as levels of conflict and rule fairness)? To answer these questions data is used from two sources: (1) a detailed household survey conducted with 1.433 households in Bolivia, Kenya, Mexico, and Uganda and (2) a more aggregated dataset from forest associations investigated by the International Forestry Resources and Institutions (IFRI) program in 10 countries. The analyses suggest that women's participation is likely when institutions exist that are less exclusionary, when households have more education, and when there is small economic inequality in general and across genders in particular. A history of women's participation, especially when women are seated on forest councils or attain leadership positions, is highly correlated with less disruptive conflict.     

A novel analysis of consumption-based carbon footprints in China: Unpacking the effects of urban settlement and rural-to-urban migration

Urbanization in developing countries greatly contributes to growing carbon emissions. Although studies have documented the urbanization effect, the science of consumption-based footprint assessments has yet to unpack various effects during the process of urbanization. Based on household expenditure data, this study innovatively proposes a methodology to conceptually and statistically deconstruct the observed urbanization effects on carbon footprint into selection effects and migration effects, which consist of human settlement effects and purposeful changes of migration (such as income and residential location). Applying propensity score matching and regression on the 2010 China Family Panel Study, we find that the apparent carbon-footprint difference between rural residents and migrants is about 1.5 t CO₂e per capita. The migration effects account for about 2/3 of the apparent difference and the remaining 1/3 is due to selection effects. Urban settlement effects and the purposeful changes account for 73% and 27% of the migration effects, respectively. Transport sector is the key driver of carbon-footprint growth: it accounts for 60% of the migration effects. We conclude that travel behavior of rural migrants, currently in scarcity in the lite rature, merits further investigation, and policies should emphasize transit-oriented land use and transportation to achieve low-carbon urbanization.     

Simply Obtained Global Radiation, Soil Temperature and SoilMoisture in an Alley Cropping System in Semi-Arid Kenya

Summary  Global radiation, soil temperature and soil moisture data were obtained from a 4–6 year old Cassia siamea/maize (CM) alley cropping (or hedgerow intercropping) system, at a semi-arid site at Machakos, Kenya, in the late eighties. With the growing need to explore and manage variations in agro-ecosystems these results deserve new attention. They quantify, in a simple but detailed manner, the influence of hedgerows on the microclimate of their intercrop and for comparison provide a sole maize (SM) control. Due to inhomogeneity of Cassia and maize, as well as limited budgets, the sampling methodology and the choice of appropriate equipment, including the sensors, demanded special attention. The diurnal patterns of soil temperatures at 7.5 cm depth represented well the shading patterns of the hedgerows. This can be developed into an operational auxiliary methodology of integrated shade quantification. With proper precautions, the developed sampling methodologies showed appropriately the time integrated values of the three microclimatic parameters with enough detail to understand yield differences between treatments and between rows. This approach may therefore be recommended for on-farm quantification of even greater spatial variability of parameters. The limitations of the selected methods are highlighted. Experiences with some alternative methods are also discussed. Received September 2, 1998/Revised June 28, 1999     

一种自动土壤水分数据质量控制预警方法

根据实时业务中传输的自动土壤水分监测数据的变化规律,对监测数据异常波动产生的异常值进行预警;通过观测值间相互关系推算相应的土壤水分常数,近似确定土壤孔隙度、最大吸湿水含量,以此确定土壤水分理论上下限并据此开展监测值的上下限预警;参考土壤含水量与水势之间的变化关系,提出水势系数的概念,直接利用计算的水势系数进行土壤水分层间变化的预警等3方面对自动土壤水分监测数据进行质控预警,并针对业务应用设计了相应的预警方案,可实时、有效地检测出异常值。从该预警方案的预警效果分析上看,预警检出率较高主要是"常数预警"和"数值变化预警",反映出小部分自动土壤水分观测站的土壤水分常数异常和部分站点业务运行维护不到位,这与野外实地考察的结论相吻合。预警效果较为客观、可靠,适用于各级土壤水分数据检测和分析服务等业务。     

Soil Carbon Sequestration and the CDM: Opportunities and Challenges for Africa

This paper examines soil carbon sequestration in developing countries in sub-Saharan Africa as part of regional and global attempts to mitigate greenhouse gas emissions and the possibility that the development of greenhouse gas mitigation projects will offer local ancillary benefits. The paper documents the improvements in agricultural practices and land-use management in sub-Saharan Africa that could increase agricultural productivity and sequester soil carbon. During the first five-year commitment period of the Kyoto Protocol, only afforestation and reforestation projects will be eligible for crediting under the Clean Development Mechanism, but soil carbon sequestration and broader sink activities could become eligible during subsequent commitment periods. However, very few cost estimates of soil carbon sequestration strategies exist, and available data are not readily comparable. It is uncertain how large amounts of carbon could be sequestered, and it is unclear how well site-specific studies represent wider areas. It is concluded that there presently is a need to launch long-term (>10 years) field experiments and demonstration and pilot projects for soil carbon sequestration in Africa. It will be important to monitor all environmental effects and carbon `costs' as well as estimate all economic benefits and costs of projects.     

Economic drivers of migration and climate change in LDCs

Environmental migration is a topic which has given rise to widespread debate and gloomy predictions about the state of the world in 2050, but where rigorous research and empirical evidence are unfortunately in short supply. In this paper, we review the existing research on and empirical evidence of how climate change and climate variability in Less Developed Countries (LDCs) affects two main drivers of migration identified by migration models in the economic literature, namely income level differentials between origin and destination areas and income variability in origin areas, and how they in turn affect migration. We find that there are serious gaps in both the economic and the environmental literature that render it impossible to make sound and robust predictions of how climate change and increased climate variability will affect the economic migration drivers, and of how these in turn may change existing migration patterns. There are some empirical indications that income differentials may increase due to lower income levels in the origin areas of LDCs, but virtually no evidence exists of the effects of climate change or increased climate variability on income variability. Furthermore, although a negative relationship between migration and rainfall has been established by many researchers, there is only very limited evidence as to what drives it. A clearer picture of the driving force behind the link between rainfall and migration would greatly benefit policymaking in this area.     

Climate change and soil freezing dynamics: historical trends and projected changes

Changes to soil freezing dynamics with climate change can modify ecosystem carbon and nutrient losses. Soil freezing is influenced strongly by both air temperature and insulation by the snowpack, and it has been hypothesized that winter climate warming may lead to increased soil freezing as a result of reduced snowpack thickness. I used weather station data to explore the relationships between winter air temperature, precipitation and soil freezing for 31 sites in Canada, ranging from the temperate zone to the high Arctic. Inter-annual climate variation and associated soil temperature variation over the last 40 years were examined and used to interpolate the effects of projected climate change on soil freezing dynamics within sites using linear regression models. Annual soil freezing days declined with increasing mean winter air temperature despite decreases in snow depth and cover, and reduced precipitation only increased annual soil freezing days in the warmest sites. Annual soil freeze–thaw cycles increased in both warm and dry winters, although the effects of precipitation were strongest in sites that experience low mean winter precipitation. Overall, it was projected that by 2050, changes in winter temperature will have a much stronger effect on annual soil freezing days and freeze–thaw cycles than changes in total precipitation, with sites close to but below freezing experiencing the largest changes in soil freezing days. These results reveal that experimental data relevant to the effects of climate changes on soil freezing dynamics and changes in associated soil physical and biological processes are lacking.     

内蒙古草原气候特点与草原生态类型区域划分

为了合理开发利用气候资源，给草原畜牧业生产的分区管理提供科学依据，文章对内蒙古草原气候特点及气候对牧草生长、畜种分布和土壤环境的影响进行了分析，发现内蒙古气候湿润度的某些等值线与土壤带的分界线几乎完全重合，表明土壤带的形成与气候条件密切相关。而气候和土壤环境是草场类型及其生态系统的主要影响因素，因此以气候湿润度为主要依据，结合内蒙古土壤带的水平分布特征，进行草原生态类型区域的划分不仅具有合理性，而且具有稳定性。指出近年来的气候增暖以及由此引起的其他气候变化，虽使草原生产力有一定的提高，但并未使内蒙古草原的生态类型有所改变。     

Adaptation to climate change through the choice of cropping system and sowing date in sub-Saharan Africa

Multiple cropping systems provide more harvest security for farmers, allow for crop intensification and furthermore influence ground cover, soil erosion, albedo, soil chemical properties, pest infestation and the carbon sequestration potential. We identify the traditional sequential cropping systems in ten sub-Saharan African countries from a survey dataset of more than 8600 households. We find that at least one sequential cropping system is traditionally used in 35% of all administrative units in the dataset, mainly including maize or groundnuts. We compare six different management scenarios and test their susceptibility as adaptation measure to climate change using the dynamic global vegetation model for managed land LPJmL. Aggregated mean crop yields in sub-Saharan Africa decrease by 6–24% due to climate change depending on the climate scenario and the management strategy. As an exception, some traditional sequential cropping systems in Kenya and South Africa gain by at least 25%. The crop yield decrease is typically weakest in sequential cropping systems and if farmers adapt the sowing date to changing climatic conditions. Crop calorific yields in single cropping systems only reach 40–55% of crop calorific yields obtained in sequential cropping systems at the end of the 21st century. The farmers’ choice of adequate crops, cropping systems and sowing dates can be an important adaptation strategy to climate change and these management options should be considered in climate change impact studies on agriculture.     

Uganda rainfall variability and prediction

This study analyzes large-scale controls on Uganda’s rainfall. Unlike past work, here, a May–October season is used because of the year-round nature of agricultural production, vegetation sensitivity to rainfall, and disease transmission. The Uganda rainfall record exhibits steady oscillations of ～3 and 6 years over 1950–2013. Correlation maps at two-season lead time resolve the subtropical ridge over global oceans as an important feature. Multi-variate environmental predictors include Dec–May south Indian Ocean sea surface temperature, east African upper zonal wind, and South Atlantic wind streamfunction, providing a 33% fit to May–Oct rainfall time series. Composite analysis indicates that cool-phase El Niño Southern Oscillation supports increased May–Oct Uganda rainfall via a zonal overturning lower westerly/upper easterly atmospheric circulation. Sea temperature anomalies are positive in the east Atlantic and negative in the west Indian Ocean in respect of wet seasons. The northern Hadley Cell plays a role in limiting the northward march of the equatorial trough from May to October. An analysis of early season floods found that moist inflow from the west Indian Ocean converges over Uganda, generating diurnal thunderstorm clusters that drift southwestward producing high runoff.     

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.