Characterizing spatial and temporal variability of crop yield caused by climate and irrigation in the North China Plain

Grain yields of wheat and maize were obtained from national statistics and simulated with an agricultural system model to investigate the effects of historical climate variability and irrigation on crop yield in the North China Plain (NCP). Both observed and simulated yields showed large temporal and spatial variability due to variations in climate and irrigation supply. Wheat yield under full irrigation (FI) was 8?t?ha^?1 or higher in 80% of seasons in the north, it ranged from 7 to 10?t?ha^?1 in 90% of seasons in central NCP, and less than 9?t?ha^?1 in 85% of seasons in the south. Reduced irrigation resulted in increased crop yield variability. Wheat yield under supplemental irrigation, i.e., to meet only 50% of irrigation water requirement [supplemental irrigation (SI)] ranged from 2.7 to 8.8?t?ha^?1 with the maximum frequency of seasons having the range of 4?C6?t?ha^?1 in the north, 4?C7?t?ha^?1 in central NCP, and 5?C8?t?ha^?1 in the south. Wheat yield under no irrigation (NI) was lower than 1?t?ha^?1 in about 50% of seasons. Considering the NCP as a whole, simulated maize yield under FI ranged from 3.9 to 11.8?t?ha^?1 with similar frequency distribution in the range of 6?C11.8?t?ha^?1 with the interval of 2?t?ha^?1. It ranged from 0 to 11.8?t?ha^?1, uniformly distributed into the range of 4?C10?t?ha^?1 under SI, and NI. The results give an insight into the levels of regional crop production affected by climate and water management strategies.     

Impacts of climate change on crop evapotranspiration with ensemble GCM projections in the North China Plain

As one of the key grain-producing regions in China, the agricultural system in the North China Plain (NCP) is vulnerable to climate change due to its limited water resources and strong dependence on irrigation for crop production. Exploring the impacts of climate change on crop evapotranspiration (ET) is of importance for water management and agricultural sustainability. The VIP (Vegetation Interface Processes) process-based ecosystem model and WRF (Weather Research and Forecasting) modeling system are applied to quantify ET responses of a wheat-maize cropping system to climate change. The ensemble projections of six General Circulation Models (GCMs) under the B2 and A2 scenarios in the 2050s over the NCP are used to account for the uncertainty of the projections. The thermal time requirements (TTR) of crops are assumed to remain constant under air warming conditions. It is found that in this case the length of the crop growth period will be shortened, which will result in the reduction of crop water consumption and possible crop productivity loss. Spatially, the changes of ET during the growth periods (ET_g) for wheat range from ?7 to 0 % with the average being ?1.5?±?1.2 % under the B2 scenario, and from ?8 to 2 % with the average being ?2.7?±?1.3 % under the A2 scenario/consistently, changes of ET_g for maize are from ?10 to 8 %, with the average being ?0.4?±?4.9 %, under the B2 scenario and from ?8 to 8 %, with the average being ?1.2?±?4.1 %, under the A2 scenario. Numerical analysis is also done on the condition that the length of the crop growth periods remains stable under the warming condition via breeding new crop varieties. In this case, TTR will be higher and the crop water requirements will increase, with the enhancement of the productivity. It is suggested that the options for adaptation to climate change include no action and accepting crop loss associated with the reduction in ET_g, or breeding new cultivars that would maintain or increase crop productivity and result in an increase in ET_g. In the latter case, attention should be paid to developing improved water conservation techniques to help compensate for the increased ET_g.     

Impact of climate change on potential evapotranspiration under a historical and future climate scenario in the Huang-Huai-Hai Plain,China

Theoretical and Applied Climatology - Climate change is widely accepted to be one of the most critical problems faced by the Huang-Huai-Hai Plain (3H Plain), which is a region in which there is an...     

华北平原夜间对流性天气对地面O3混合比的抬升效应

2013年6—9月在河北省固城站观测到多次夜间对流性天气伴随地面O₃混合比快速抬升的过程,并引起次日清晨到中午O₃混合比升高。大多数对流过程中,O₃混合比在半小时内升高至60×10-9～80×10-9,同时NO_x等反应性气体混合比下降,θ_se值降低,说明下沉气流将高空气团带到地面,造成了O₃混合比的升高。通过再分析资料得到下沉气团基本来源于对流层中下层,这一结论与当地进行的一次飞机观测结果吻合。多数对流过程中固城站和北京城区地面O₃混合比和θ_se值有相同的变化趋势和程度。根据观测结果,推测华北地区在夏季和初秋时,对流层中下层存在O₃高值区,混合比约为60×10-9～80×10-9。对流性天气对地面O₃抬升的影响区域与对流系统的影响范围有关,可达到中尺度范围。华北地区光化学污染严重,对流性天气引起的地面O₃混合比抬升程度比较强,对环境的影响值得关注。     

Effects of climate change on grain maize yield potential in the european community

Grain maize yield in the main arable areas of the European Community (E.C.) was calculated with a simulation model, WOFOST, using historical weather data and average soil characteristics. The sensitivity of the model to individual weather variables was determined. Subsequent analyses were made using climate change scenarios with and without the direct effects of increased atmospheric CO₂. The impact of crop management (sowing date, irrigation and cultivar type) in a changed climate was also assessed. Scenario climate change generally results in larger grain yields for the northern E.C., similar or slightly smaller yields for the central E.C. and considerably smaller yields for the southern E.C. The various climate change scenarios used appear to give considerably different changes in grain yield, both for each location and for the E.C. as a whole. Management analyses show that for both current and scenario climates the largest grain yield will be attained by varieties with an early start of grain filling, that average irrigation requirements to attain potential grain yield in the E.C. will increase with climate change but will decrease with both increased CO₂ and climate change, and that sowing at both current and scenarios climate should occur as early as possible.The U.S. Government right to retain a nonexclusive, royalty-free licence in and to any copyright is acknowledged.     

RegCM4对华北区域21世纪气候变化预估研究

利用国家气候中心完成的RegCM4区域气候模式在RCP4.5和RCP8.5两种排放路径下的气候变化动力降尺度试验结果,在检验模式对基准期(1986—2005年)气温和降水模拟能力基础上,进行华北区域21世纪气候变化预估分析。结果表明：RegCM4对华北区域基准期气温和降水的模拟能力较好。未来21世纪,两种情景下华北区域气温、降水、持续干期(consecutive dry days, CDD)和强降水量(R95p)变化逐渐增大,但变化幅度在高排放的RCP8.5情景下更为显著,其中近期(2021—2035年)、中期(2046—2065年)、远期(2080—2098年)RCP8.5情景下年平均气温分别升高1.77、3.44、5.82℃,年平均降水分别增加8.1%、14%、19.3%,CDD分别减少3、3、12 d, R95p分别增加30.8%、41.9%、69.8%。空间上,未来21世纪华北区域内年、冬季、夏季平均气温将一致升高,夏季升温幅度最大;年、冬季、夏季平均降水整体以增加为主,冬季降水增加幅度最大;CDD以减少为主,但近期和中期在山西和京津冀有所增加,而R95p以增加为主,表明21世...     

Impact of climate change on agriculture in Northern Norway and potential strategies for adaptation

This study evaluates the effects of climate change on agriculture in Northern Norway. It is based on downscaled climate projections for six different municipalities combined with interviews with farmers, advisors and administrative personnel in these municipalities. The projections document large climatic differences both between and within the different municipalities. The main predicted climatic changes include increasing temperatures and precipitation as well as increased frequency of certain types of extreme weather events. Despite challenges such as unstable winters, increased autumn precipitation and possibly more weeds and diseases, a prolongation of the current short growth season together with higher growth temperatures can give new opportunities for agriculture here. The impacts are expected to differ both within and between municipalities and will require tailored adaptive strategies. Most of these however should pose no difficulty implementing, having an agronomical basis that farmers are accustomed to cope with.     

Expert views of climate change adaptation in the Maldives

This essay assesses the ??Integrating Climate Change Risks into Resilient Island Planning in the Maldives?? Program, or ICCR, a four-year $9.3 million adaptation project supported by the Least Developed Countries Fund, Maldivian Government and the United Nations Development Program. The essay elaborates on the types of challenges that arise as a low-income country tries to utilize international development assistance to adapt to climate change. Based primarily on a series of semi-structured research interviews with Maldivian experts, discussed benefits to the ICCR include improving physical resilience by deploying ??soft?? infrastructure, institutional resilience by training policymakers, and community resilience by strengthening assets. Challenges include ensuring that adaptation efforts are sufficient to reduce vulnerability, lack of coordination, and the values and attitudes of business and community leaders.     

Smallholders adaptation to climate change in Mali

This study was undertaken to assess the potential impacts of climate change on agriculture in the Sikasso region of southern Mali, as part of an effort by the U.S. Agency for International Development (USAID) to integrate climate change adaptation considerations into their development projects. The region is considered to be the breadbasket of Mali, providing a substantial amount of the country’s food supplies as well as cotton for exchange earnings. The project had two components: modeling how climate change could affect production of cereal and cash crops in southern Mali; and conducting a stakeholder-driven vulnerability and adaptation assessment to identify potential options for addressing current and projected risks to agriculture from climate change. Projected changes in crop yields were based on a previous analysis that was extended for the purposes of this study. The projections suggested that the sensitivity of maize to changing weather conditions is relatively small (generally less than 10% change) under both dry and wet scenarios in 2030 and 2060. White (Irish) potatoes, the primary cash crop, are the most sensitive to changing weather conditions, with yields decreasing under both dry and wet conditions; yields could decrease by about 25% by 2060. Stakeholder workshops, field interviews, and an expert analysis were used to assess current and future climate-related vulnerability and to identify potential adaptation options. The main focus of the assessment was farmers in a village of about 3,000 people in the Sikasso region that practiced a rice-potato rotation system typical to the region. The farmers emphasized adaptation measures that require outside financial and technical assistance, for example installation of a water gate that would retain more water in the inland valley and increase the water table to flood rice fields during the rainy season and for furrow irrigation of potatoes during the dry season. Adaptations emphasized by both the farmers and representatives of regional technical services were crop diversification and germplasm improvement; soil and water management; access to equipment (plows, carts, oxen, and improved stoves); credit stockage villageois (CSV); and fertilizer.     

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.     

Potential impact of future climate change on crop yield in northeastern China

We evaluated the potential impact of future climate change on spring maize and single-crop rice in northeastern China(NEC) by employing climate and crop models. Based on historical data, diurnal temperature change exhibited a distinct negative relationship with maize yield, whereas minimum temperature correlated positively to rice yield. Corresponding to the evaluated climate change derived from coupled climate models included in the Coupled Model Intercomparison Project Phase 5(CMIP5) under the Representative Concentration Pathway 4.5 scenario(RCP4.5), the projected maize yield changes for three future periods [2010–39(period 1), 2040–69(period 2), and 2070–99(period 3)] relative to the mean yield in the baseline period(1976–2005) were 2.92%, 3.11% and 2.63%, respectively. By contrast, the evaluated rice yields showed slightly larger increases of 7.19%, 12.39%, and 14.83%, respectively. The uncertainties in the crop response are discussed by considering the uncertainties obtained from both the climate and the crop models. The range of impact of the uncertainty became markedly wider when integrating these two sources of uncertainty. The probabilistic assessments of the evaluated change showed maize yield to be relatively stable from period 1 to period 3, while the rice yield showed an increasing trend over time. The results presented in this paper suggest a tendency of the yields of maize and rice in NEC to increase(but with great uncertainty) against the background of global warming, which may offer some valuable guidance to government policymakers.     

Everyday realities of climate change adaptation in Mozambique

This paper analyzes discourses and practices of flood response and adaptation to climate change in Mozambique. It builds on recent publications on climate change adaptation that suggest that the successes and failures of adaptation highly depend on the cultural and political realms of societal perceptions and the sensitivity of institutions. To capture this, the paper adopted a multi-sited ethnographic approach. Acknowledging that there is no central locus of representation that can unveil the working of disaster response in Mozambique, the paper brings together five vignettes of research in different ‘sites’ of concern to the rise in floods in Mozambique. These are the politics of climate change adaptation at the national institutional level, societal responses to increased flooding, local people's responses to floods, the evacuation and resettlement programme following the 2007 flood. The paper finds how adaptation to climate change becomes part of everyday politics, how actors aim to incorporate responses into the continuation of their normal behavior and how elites are better positioned to take advantage of adaptation programmes than the vulnerable people that were targeted. It argues that climate change adaptation must be made consonant with historically grown and ongoing social and institutional processes. It concludes with lessons that the analysis and methodology of the research can provide for the practice of climate change adaptation.     

华北平原地下水灌溉对区域气候影响的数值模拟

在耦合模式WRF/Noah-MP中加入考虑地下水过程的动态灌溉方案,设计两组试验（分别为考虑和不考虑地下水灌溉）,连续模拟10 a（2001—2010年）,来研究华北平原地下水灌溉的区域气候效应。结果表明,地下水灌溉导致华北平原地下水位下降,在少雨的季节灌溉量大,水位下降较快。在灌溉期（3—9月）,灌溉引起的土壤湿度升高影响了地表能量的分配（潜热增加,感热减少）,导致2 m气温显著降低0.6—1.0℃,同时也降低了灌溉区夏季模拟偏高的气温。灌溉对灌溉区边界层大气有升高湿度和冷却降温的作用,对春季的影响局限在边界层内,而夏季的影响持续到5000 m以上。夏季灌溉对降水的影响远强于春季,灌溉的升高湿度和冷却效应分别对夏季降水产生正反馈和负反馈,共同影响灌溉区的降水变化。灌溉通过对水汽输送的影响,引起非灌溉区降水的变化,而长江中下游流域夏季降水的增多可能与高空西风急流轴位置南移有关。      

Sharing the burden of financing adaptation to climate change

Climate change may cause most harm to countries that have historically contributed the least to greenhouse gas emissions and land-use change. This paper identifies consequentialist and non-consequentialist ethical principles to guide a fair international burden-sharing scheme of climate change adaptation costs. We use these ethical principles to derive political principles – historical responsibility and capacity to pay – that can be applied in assigning a share of the financial burden to individual countries. We then propose a hybrid ‘common but differentiated responsibilities and respective capabilities’ approach as a promising starting point for international negotiations on the design of burden-sharing schemes. A numerical assessment of seven scenarios shows that the countries of Annex I of the United Nations Framework Convention on Climate Change would bear the bulk of the costs of adaptation, but contributions differ substantially subject to the choice of a capacity to pay indicator. The contributions are less sensitive to choices related to responsibility calculations, apart from those associated with land-use-related emissions. Assuming costs of climate adaptation of USD 100 billion per year, the total financial contribution by the Annex I countries would be in the range of USD 65–70 billion per year. Expressed as a per capita basis, this gives a range of USD 43–82 per capita per year.     

The impact of future climate change and potential adaptation methods on Maize yields in West Africa

Using recent advances in statistical crop yield modelling and a unique dataset consisting of yield time series for Russian regions over the period from 1955 to 2012, the study investigates the potential impact of climate change (CC) on the productivity of the three most important grains. Holding current grain growing areas fixed, the aggregate productivity of the three grains is predicted to decrease by 6.7% in 2046–2065 and increase by 2.6% in 2081–2100 compared to 1971–2000 under the most optimistic representative emission concentration pathway (RCP). Based on the projections for the three other RCPs, the aggregate productivity of the three studied crops is assessed to decrease by 18.0, 7.9 and 26.0% in the medium term and by 31.2, 25.9 and 55.4% by the end of the century. Our results indicate that CC might have a positive effect on winter wheat, spring wheat and spring barley productivity in a number of regions in the Northern and Siberian parts of Russia. However, due to the highly damaging CC impact on grain production in the most productive regions located in the South of the country, the overall impact tends to be negative. Therefore, a shift of agricultural production to the Northern regions of the country could reduce the negative impact of CC on grain production only to a limited extent. More vigorous adaptation measures are required to maintain current grain production volumes in Russia under CC.     

Least-cost adaptation options for global climate change impacts on the Brazilian electric power system

Global climate change induced by the emission of greenhouse gases may pose challenges to energy security. The vulnerability of energy sources, in particular of renewable sources, to climate change raises the need to identify adaptation measures. This paper applies an integrated resource planning approach to calculate least-cost adaptation measures to a set of projected climate impacts on the Brazilian power sector. The methodology used has the advantage of finding optimal solutions that take into consideration the whole energy chain and the interactions between energy supply and demand. Results point in the direction of an increased installed capacity based, mostly, on natural gas, but also sugarcane bagasse, wind power and coal/nuclear plants, to compensate for a lower reliability of hydroelectric production, amongst other impacts. The indirect effect of these results is the displacement of natural gas from other consuming sectors, such as industry, in favor of its use for power generation. Results obtained are, however, based on the techno-economic premises used in the simulation, which may vary in the long term.