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.     

Influence of irrigated agriculture on diurnal surface energy and water fluxes, surface climate, and atmospheric circulation in California

The impact of land use change on regional climate can be substantial but also is variable in space and time. Past observational and modeling work suggests that in a ‘Mediterranean’ climate such as in California’s Central Valley, the impact of irrigated agriculture can be large in the dry season but negligible in the wet season due to seasonal variation in surface energy partitioning. Here we report further analysis of regional climate model simulations showing that diurnal variation in the impact of irrigated agriculture on climate similarly reflects variation in surface energy partitioning, as well as smaller changes in net radiation. With conversion of natural vegetation to irrigated agriculture, statistically significant decreases of 4–8?K at 2?m occurred at midday June–September, and small decreases of ~1?K occurred in winter months only in relatively dry years. This corresponded to reduced sensible heat flux of 100–350?W?m^?2 and increased latent heat fluxes of 200–450?W?m^?2 at the same times and in the same months. We also observed decreases of up to 1,500?m in boundary layer height at midday in summer months, and marginally significant reductions in surface zonal wind speed in July and August at 19:00 PST. The large decrease in daytime temperature due to shifts in energy partitioning overwhelmed any temperature increase related to the reduced zonal sea breeze. Such changes in climate and atmospheric dynamics from conversion to (or away from) irrigated agriculture could have important implications for regional air quality in California’s Central Valley.     

Intra-seasonal rainfall and piped water revenue variability in rural Africa

Rainfall patterns influence water usage and revenue from user payments in rural Africa. We explore these dynamics by examining monthly rainfall against 4,888 records of rural piped water revenue in Ghana, Rwanda, and Uganda and quantifying revenue changes over 635 transitions between dry and wet seasons.Results show operators experience revenue variability at regional and intra-seasonal scales. Revenues fall by an average of 30 percent during the wettest months of the year in climate regimes with consistent wet season rainfall. However, seasonally stable revenues are observed in areas where consecutive dry days are common during the wet season, potentially reflecting a dependency on reliable services. We also find changes in tariff level, waterpoint connection type, and payment approach do not consistently prevent or increase seasonal revenue variability.Local revenue generation underpins delivery of drinking water services. Where rainfall patterns remain consistent, piped water operators can expect to encounter seasonal revenue reductions regardless of whether services are provided on or off premises and of how services are paid for. Revenue projections that assume consistent volumetric demand year-round may lead to shortfalls that threaten sustainability and undermine the case for future investment. Intra-seasonal rainfall analysis can enhance rural piped water revenue planning by offering localised insight into demand dynamics and revealing where climate variability may increase dependency on reliable services.     

Indigenous perception of changes in climate variability and its relationship with agriculture in a Zoque community of Chiapas, Mexico

This study analyses the perceptions of Zoque indigenous men and women of changes in climate variability, indicated by rainfall and temperature records from the region. Peasant farmers perceive decreases in rainfall and increases in temperature as these factors are related to modifications in the corn planting season and the introduction of crops which were usually only found in hot regions. The climate changes in the zone are attributed to vegetation loss and the eruption of the Chichón volcano in 1982. The Zoque perception is structured according to cultural and individual experience, tied to agriculture and the annual weather calendar. The volcanic eruption offers a significant chronological reference point in order to explain different environmental transformations, such as climate, within Zoque territory. Perception is the mental picture of local climate variability changes and the responses in seasonal agriculture modifications, utilizing individual and cultural experiences which are vulnerable to economic and environmental change.     

Long-Term Variations in Seasonal Weather Conditions Important to Corn Production in Illinois

An analysis of long-term records ofcorn yields and seasonal weather conditions inIllinois found major temporal shifts and importantspatial variations in the types of seasonal weatherconditions, expressed as the normality of temperatureand rainfall conditions, that create positive andnegative impacts on yields. Nineteen different typesof corn-weather seasons (May–August) occurred during1901–1997, and 9 of these seasons accounted for mostof the high corn yields (top 20 of the 97) and 8seasonal types produced most low yields (lowest 20values). Assessment of the years with either high orlow yields revealed (1) some corn-weather seasonaltypes were uniformly distributed throughout thecentury; (2) others were unevenly time distributed,some occurring only in early decades and others onlyin the last few decades; and (3) certain weather typesvaried regionally. The yield responses to certainseasonal types varied over time, being good early andnot so later, or vice versa. The findings indicatethat time changes in farming practices, cornvarieties, and agricultural technology have alteredhow certain types of growing season weather affectcorn yields. Regional differences in yield outcomesfrom a given set of weather conditions reflect varyingsoil and climate differences across Illinois. Thespatial and temporal differences reveal the importanceof using weather-impact results to define seasonalweather extremes. The kinds of seasons creating highyields predominated during 1901–1910 and 1961–1997,and most seasons creating low yields were concentratedbetween 1911 and 1960. Comparison of the 1901–1997temporal distributions of yield extremes (high andlow) with the temporal distributions of cyclonepassages and the incidence of ENSO conditions thataffect growing season weather conditions revealed agenerally good relationship. The shifting temporalresponses to various kinds of seasonal weatherconditions during the 20th century reveal some ofthe difficulties facing efforts to project realisticand detailed impacts in agriculture from alteredfuture seasonal weather conditions.     

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.     

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.     

Assessing the spatial impact of climate on wheat productivity and the potential value of climate forecasts at a regional level

Quantification of the spatial impact of climate on crop productivity and the potential value of seasonal climate forecasts can effectively assist the strategic planning of crop layout and help to understand to what extent climate risk can be managed through responsive management strategies at a regional level. A simulation study was carried out to assess the climate impact on the performance of a dryland wheat-fallow system and the potential value of seasonal climate forecasts in nitrogen management in the Murray-Darling Basin (MDB) of Australia. Daily climate data (1889–2002) from 57 stations were used with the agricultural systems simulator (APSIM) to simulate wheat productivity and nitrogen requirement as affected by climate. On a good soil, simulated grain yield ranged from <2 t/ha in west inland to >7 t/ha in the east border regions. Optimal nitrogen rates ranged from <60 kgN/ha/yr to >200 kgN/ha/yr. Simulated gross margin was in the range of –$20/ha to $700/ha, increasing eastwards. Wheat yield was closely related to rainfall in the growing season and the stored soil moisture at sowing time. The impact of stored soil moisture increased from southwest to northeast. Simulated annual deep drainage ranged from zero in western inland to >200 mm in the east. Nitrogen management, optimised based on ‘perfect’ knowledge of daily weather in the coming season, could add value of $26～$79/ha compared to management optimised based on historical climate, with the maximum occurring in central to western part of MDB. It would also reduce the nitrogen application by 5～25 kgN/ha in the main cropping areas. Comparison of simulation results with the current land use mapping in MDB revealed that the western boundary of the current cropping zone approximated the isolines of 160 mm of growing season rainfall, 2.5t/ha of wheat grain yield, and $150/ha of gross margin in QLD and NSW. In VIC and SA, the 160-mm isohyets corresponded relatively lower simulated yield due to less stored soil water. Impacts of other factors like soil types were also discussed.     

Climate Change and Global Wine Quality

From 1950 to 1999 the majority of the world's highest quality wine-producing regions experienced growing season warming trends. Vintage quality ratings during this same time period increased significantly while year-to-year variation declined. While improved winemaking knowledge and husbandry practices contributed to the better vintages it was shown that climate had, and will likely always have, a significant role in quality variations. This study revealed that the impacts of climate change are not likely to be uniform across all varieties and regions. Currently, many European regions appear to be at or near their optimum growing season temperatures, while the relationships are less defined in the New World viticulture regions. For future climates, model output for global wine producing regions predicts an average warming of 2 ^∘C in the next 50 yr. For regions producing high-quality grapes at the margins of their climatic limits, these results suggest that future climate change will exceed a climatic threshold such that the ripening of balanced fruit required for existing varieties and wine styles will become progressively more difficult. In other regions, historical and predicted climate changes could push some regions into more optimal climatic regimes for the production of current varietals. In addition, the warmer conditions could lead to more poleward locations potentially becoming more conducive to grape growing and wine production.     

Conservation,contraception and controversy: Supporting human rights to enable sustainable fisheries in Madagascar

Environmental NGOs are increasingly called upon to respect human rights when undertaking conservation programs. Evaluating a family planning program running alongside marine management measures in Madagascar, we find that family planning services provided by an environmental NGO can support women’s reproductive rights. Family planning services allow the option of smaller families, and give more time to work, increased income and better health. These benefits do not translate into increased support for, or participation in, marine management, however, and women who are able to work more are typically fishing more. We identify patriarchal norms as a key factor preventing the family planning programme from manifesting in improved resource stewardship, limiting opportunities for women to participate fully in resource management meetings and diversify their livelihood outside traditional tasks, including fishing. We propose that a successful human rights-based approach must be more comprehensive, targeting multiple rights and challenging existing institutions and power structures.     

Using climate information for supporting climate change adaptation in water resource management in South Africa

Water resources, and in particular run-off, are significantly affected by climate variability. At present, there are few examples of how the water management sector integrates information about changing intra-annual climate conditions in a systematic manner in developing countries. This paper, using the case study of Cape Town in the Western Cape, South Africa, identifies processes and products to facilitate increased uptake of seasonal climate forecasts among water resource managers. Results suggest that existing seasonal forecasts do not focus enough on specific users’ needs. In order to increase uptake, forecasts need to include information on the likely impact of precipitation variability on runoff and water availability. More opportunities are also needed for those with climate knowledge to interact with water resource managers, particularly in the developing country context where municipal managers’ capacity is strained. Although there are challenges that need to be overcome in using probabilistic climate information, seasonal forecast information tailored to the needs of water resource planners has the potential to support annual planning and is therefore a means of adapting to climate change.     

1982~1999年中国地区叶面积指数变化及其与气候变化的关系

利用1982～1999年AVHRR Pathfinder卫星遥感观测的植被叶面积指数（leaf area index,LAI）资料和中国730个气象台站的温度、降水观测资料,研究了中国不同地区（东北地区、华北地区、长江流域、华南地区和西南地区）LAI的季节、生长季和年变化,及其与气候变化（温度、降水）的关系。结果表明,在中国大部分地区,年平均LAI和生长季平均LAI均是增加的。由于区域和季节气候的差异,LAI变化趋势具有明显的空间和季节非均一性。从区域平均的角度来看,不同地区年和生长季平均LAI都有增加趋势,并且在华南地区增加最快。因而,在全球变化背景下,华南地区可能是潜在的碳汇。在季节尺度上,各地区区域平均LAI基本上都是增加的,并且都在春季增加最快。温度变化是LAI变化的主要原因。但是人类活动如农业活动、城市化等对华北平原、长江三角洲和珠江三角洲等地区LAI变化的作用不容忽视。     

Indigenous climate knowledge in southern Uganda: the multiple components of a dynamic regional system

Farmers in southern Uganda seek information to anticipate the interannual variability in the timing and amount of precipitation, a matter of great importance to them since they rely on rain-fed agriculture for food supplies and income. The four major components of their knowledge system are: (1) longstanding familiarity with the seasonal patterns of precipitation and temperature, (2) a set of local traditional climate indicators, (3) observation of meteorological events, (4) information about the progress of the seasons elsewhere in the region. We examine these components and show the connections among them. We discuss the social contexts in which this information is perceived, evaluated, discussed and applied, and we consider the cultural frameworks that support the use of this information. This system of indigenous knowledge leads farmers to participate as agents as well as consumers in programs that use modern climate science to plan for and adapt to climate variability and climate change.     

Crop yield response to economic, site and climatic variables

This paper examines the effects of climatic and non-climatic factors on the mean and variance of corn, soybean and winter wheat yield in southwestern Ontario, Canada over a period of 26 years. Average crop yields increase at a decreasing rate with the quantity of inputs used, and decrease with the area planted to the crop. Climate variables have a major impact on mean yield with the length of the growing season being the primary determinant across all three crops. Increases in the variability of temperature and precipitation decrease mean yield and increase its variance. Yield variance is poorly explained by both seasonal and monthly climate variable models. Projections of future climate change suggest that average crop yield will increase with warmer temperatures and a longer growing season which is only partially offset by forecast increases in the variability of temperature and rainfall. The projections would also depend on future technological developments, which have generated significant increases in yield over time despite changing annual weather conditions.     

Impact of climate change on mid-twenty-first century growing seasons in Africa

Changes in growing seasons for 2041–2060 across Africa are projected using a regional climate model at 90-km resolution, and confidence in the predictions is evaluated. The response is highly regional over West Africa, with decreases in growing season days up to 20% in the western Guinean coast and some regions to the east experiencing 5–10% increases. A longer growing season up to 30% in the central and eastern Sahel is predicted, with shorter seasons in parts of the western Sahel. In East Africa, the short rains (boreal fall) growing season is extended as the Indian Ocean warms, but anomalous mid-tropospheric moisture divergence and a northward shift of Sahel rainfall severely curtails the long rains (boreal spring) season. Enhanced rainfall in January and February increases the growing season in the Congo basin by 5–15% in association with enhanced southwesterly moisture transport from the tropical Atlantic. In Angola and the southern Congo basin, 40–80% reductions in austral spring growing season days are associated with reduced precipitation and increased evapotranspiration. Large simulated reductions in growing season over southeastern Africa are judged to be inaccurate because they occur due to a reduction in rainfall in winter which is over-produced in the model. Only small decreases in the actual growing season are simulated when evapotranspiration increases in the warmer climate. The continent-wide changes in growing season are primarily the result of increased evapotranspiration over the warmed land, changes in the intensity and seasonal cycle of the thermal low, and warming of the Indian Ocean.     

中国东部季风区植被物候季节变化对气候响应的大尺度特征：年际比较

利用1982～1993年NOAA/NASA PathfinderAVHRR陆地数据集中的NDVI数据集,在中国东部植被生长的不同阶段(全年、植被生长季、植被生长季的增长阶段和衰退阶段),对植被季节生长对气候响应的年际变化进行了分析,发现：(1)无论在多年平均意义上还是逐年来看,中国东部季风区植被季节性生长状况对温度的响应在各个生长阶段都是近于同步的,温度对于植被生长季节变化的驱动关系非常稳定;(2)逐年来看,植被季节性生长对降水的响应也是存在的,但相关关系和相关的滞后关系具有年际差异。通过定量化地分析中国东部植被季节生长对季风气候响应的年际变化,有助于对陆面过程模式中的有关部分进行改进,从而提高对中国东部区域年际气候变化的模拟能力。     

1881—2010年哈尔滨市气候变化及其影响

利用哈尔滨站1881—2010年的月平均气温、1909—2010年的月总降水量和1961—2010年哈尔滨所辖区、县（市）月平均气温、月总降水量资料,采用线性趋势分析方法,计算了哈尔滨市气温、降水变化速率,分析了哈尔滨市气候变化特征;阐述了气候变化对哈尔滨市的影响。结果表明：近50 a,除巴彦7月气温略呈下降趋势外,哈尔滨市各区、县（市）各月、季、年平均气温均呈升高趋势。哈尔滨各区、县（市）各月、季、年总降水量变化趋势不一致。近130 a,哈尔滨市年、季平均气温均呈明显的上升趋势,20世纪80年代开始明显增温,21世纪开始增温尤为显著。近百年来,哈尔滨市年、季总降水量均呈减少趋势。气候变化对哈尔滨市农业、能源等方面的影响有利有弊,但对于水资源、人体健康和交通等有较大的负面影响。     

2019年贵州省夏收粮油作物生长季农业气候评价

根据贵州省84个气象观测站的资料,分析2018-2019年夏收粮油作物生长季内的气温、降水、日照3个气象要素的变化特点,结合作物生物学特性对气象的要求,并与历史同期气候条件进行对比,评估2018-2019年夏收粮油作物生长季内气候条件对农业生产的影响。结论为:小麦主产区大部光温水条件匹配较好。油菜生长季前期光热条件较差,生育期明显推迟,长势差于2018年,但后期天气转好,利于推进油菜生育进程和产量形成。春播马铃薯气候条件明显好于冬播马铃薯,利于全年马铃薯产量的稳产,冬播马铃薯主产区受阴雨寡照天气影响明显。夏收粮油作物全生育期内无大范围重大农业气象灾害,农业气象条件总体有利于夏收粮油作物生长发育和产量形成,属于较好农业气候年景。     

ENSEMBLES-based assessment of regional climate effects in Luxembourg and their impact on vegetation

Projected future regional climate changes in Luxembourg are assessed based on a six-member ensemble of regional climate models (RCM) from the ENSEMBLES project. The key aspects are projected changes in air temperature and their impacts on vegetation. Up to now, there have been only few assessments of future climate conditions for Luxembourg. As agriculture is the dominant land use in Luxembourg, possible effects on crops and vegetation in general are highly relevant. Different RCMs at 25 km spatial and a daily temporal resolution, ranging from 1961 to 2100 based on the SRES A1B emission scenario are used. To reduce systematic biases in the RCM-derived time series, a bias correction is applied. Multi-model annual mean temperatures are projected to increase by 3.1 °C between the reference time span (1961 to 1990) and the far future (2069 to 2098). Clear change signals are found in seasonal bivariate frequency distributions of air temperature and precipitation. Derived impacts are an elongation of the thermal vegetation period by 6.2 days per decade due to an earlier onset in spring; growing degree day sums show a substantial increase leading to potentially better growth conditions; the earlier onset of the vegetation period causes an increase in late frost risk, especially in the near future (2021 to 2050) projections compared to the reference period.     

Climate change alters growing season flux dynamics in mesic grasslands

Changing climate could affect the functioning of grassland ecosystems through variation in climate forcings and by altering the interactions of forcings with ecological processes. Both the short and long-term effects of changing forcings and ecosystem interactions are a critical part of future impacts to ecosystem ecology and hydrology. To explore these interactions and identify possible characteristics of climate change impacts to mesic grasslands, we employ a low-dimensional modeling framework to assess the IPCC A1B scenario projections for the Central Plains of the United States; forcings include increased precipitation variability, increased potential evaporation, and earlier growing season onset. These forcings are also evaluated by simulations of vegetation photosynthetic capacity to explore the seasonal characteristics of the vegetation carbon assimilation response for species at the Konza Prairie in North Central Kansas, USA. The climate change simulations show decreases in mean annual soil moisture and and carbon assimilation and increased variation in water and carbon fluxes during the growing season. Simulations of the vegetation response show increased variation at the species-level instead of at a larger class scale, with important heterogeneity in how individual species respond to climate forcings. Understanding the drivers and relationships behind these ecosystem responses is important for understanding the likely scale of climate change impacts and for exploring the mechanisms shaping growing season dynamics in grassland ecosystems.