气候变化背景下吉林省春玉米冷害特征研究

为了研究气候变化背景下过去55年及未来35年吉林省春玉米冷害的时空变化特征,笔者利用气象行业标准《北方春玉米冷害评估技术规范》规定的指标和计算方法,分析了1961—2015年以及2种未来气候情景（RCP4.5和RCP8.5）下2016—2050年吉林省春玉米冷害的时空分布特征。结果表明：（1）1961–2015年及2种情景下2016—2050年各地区5—9月月平均气温之和均呈增加趋势,但RCP8.5情景下的5—9月月平均气温之和均高于RCP4.5情景。（2）1961—2015年吉林省西部和中部中度冷害发生频率较高,东部重度冷害发生频率较高。（3）RCP4.5情景下冷害频率高于RCP8.5情景,冷害均集中在东部。（4）1996年之前春玉米冷害范围以大范围冷害为主,之后均为局部冷害;RCP4.5情景下以区域性冷害发生为主;RCP8.5情景下以局部冷害为主。未来气候变暖背景下吉林春玉米冷害时空变化特征研究结果可为吉林省农业生产的防灾减灾工作提供技术支撑。     

Combined impacts of climate and nutrient fertilization on yields of pearl millet in Niger

Effects of climate variability and change on yields of pearl millet have frequently been evaluated but yield responses to combined changes in crop management and climate are not well understood. The objectives of this study were to determine the combined effects of nutrient fertilization management and climatic variability on yield of pearl millet in the Republic of Niger. Considered fertilization treatments refer to (i) no fertilization and the use of (ii) crop residues, (iii) mineral fertilizer and (iv) a combination of both. A crop simulation model (DSSAT 4.5) was evaluated by using data from field experiments reported in the literature and applied to estimate pearl millet yields for two historical periods and under projected climate change. Combination of crop residues and mineral fertilizer resulted in higher pearl millet yields compared to sole application of crop residues or fertilizer. Pearl millet yields showed a strong response to mean temperature under all fertilization practices except the combined treatment in which yields showed higher correlation to precipitation. The crop model reproduced reported yields well including the detected sensitivity of crop yields to mean temperature, but underestimated the response of yields to precipitation for the treatments in which crop residues were applied. The crop model simulated yield declines due to projected climate change by −11 to −62% depending on the scenario and time period. Future crop yields in the combined crop residues + fertilizer treatment were still larger than crop yields in the control treatment with baseline climate, underlining the importance of crop management for climate change adaptation. We conclude that nutrient fertilization and other crop yield limiting factors need to be considered when analyzing and assessing the impact of climate variability and change on crop yields.     

Evaluation of regional climate scenario data for impact assessment of climate change on rice productivity in Korea

Spatial evaluation of the uncertainty associated with climate data would allow reliable interpretation of simulation results for regional crop yield using gridded climate data as input to a crop growth model. The objective of this study was to examine the spatial uncertainty of regional climate model data through determining optimal seeding date with the ORYZA2000 model for assessment of climate change impact on rice productivity in Korea. The optimal seeding date was determined at each grid point using regional climate model outputs under the RCP 8.5 scenarios. In major rice production areas such as inland plain regions, where temperatures of regional climate data were relatively accurate, the optimal seeding date determined using those gridded data were reasonable. However, areas with complex terrains including areas near bodies of water, e.g. coastal areas, riverbasins, lakes, and mountainous areas, had a relatively large uncertainty of the optimal seeding date determined using the regional climate data. These results indicated that the uncertainty of regional climate data at a high spatial resolution of 12.5 km should be taken into account in the regional impact assessment based on crop growth simulations in Korea. In addition, further studies would be merited to assess the impact of climate change on rice yield at an ultra-high spatial resolution of 1 km in Korea. Crop yields were projected to decrease after the 2020s when crop yield simulations from inland plain areas were considered, which suggested that adaptation strategies should be established and implemented in the near future.     

阴雨寡照灾害对云南烤烟的种植风险预测

阴雨寡照灾害在未来将具有"空间+时间动态性"的变化特征.笔者根据烤烟种植适宜性指标和阴雨寡照等级指标,利用1981-2010年连续30年的逐日气象观测资料和2021-2050年全球气候模式HadGEM2-ES的RCPs排放情景预估结果,结合灾害系统理论,采用多元回归、"距平逼近"插值和栅格运算等方法,分析阴雨寡照灾害对...     

Global warming likely reduces crop yield and water availability of the dryland cropping systems in the U.S. Central Great Plains

We investigated the impact of GCM-projected climate change on dryland crop rotations of wheat-fallow and wheat-corn-fallow in the Central Great Plains (Akron in Colorado, USA) using the CERES 4.0 crop modules in RZWQM2. The climate change scenarios for CO₂, temperature, and precipitation were produced by 22 GCM projections for Colorado based on the A1B scenario. The climate change for years 2050 and 2075 was super-imposed on measured 30-year-baseline climate data (1989–2008). For all the cropping rotations and projection years, simulated yields of wheat and corn decreased significantly (P < 0.05) with increasing temperatures. The yield declines due to the elevated temperatures should be attributable to the shortening of crop maturity duration and concurrent decreases in soil water and evapotranspiration. The model was also projected to decrease crop yields for the combined climate change scenarios of CO₂, temperature, and precipitation in the dryland cropping rotations.     

Impacts and adaptation of European crop production systems to climate change

The studies on anthropogenic climate change performed in the last decade over Europe show consistent projections of increases in temperature and different patterns of precipitation with widespread increases in northern Europe and decreases over parts of southern and eastern Europe. In many countries and in recent years there is a tendency towards cereal grain yield stagnation and increased yield variability. Some of these trends may have been influenced by the recent climatic changes over Europe.A set of qualitative and quantitative questionnaires on perceived risks and foreseen impacts of climate and climate change on agriculture in Europe was distributed to agro-climatic and agronomy experts in 26 countries. Europe was divided into 13 Environmental Zones (EZ). In total, we had 50 individual responses for specific EZ. The questionnaires provided both country and EZ specific information on the: (1) main vulnerabilities of crops and cropping systems under present climate; (2) estimates of climate change impacts on the production of nine selected crops; (3) possible adaptation options as well as (4) adaptation observed so far. In addition we focused on the overall awareness and presence of warning and decision support systems with relevance for adaptation to climate change.The results show that farmers across Europe are currently adapting to climate change, in particular in terms of changing timing of cultivation and selecting other crop species and cultivars. The responses in the questionnaires show a surprisingly high proportion of negative expectations concerning the impacts of climate change on crops and crop production throughout Europe, even in the cool temperate northern European countries.The expected impacts, both positive and negative, are just as large in northern Europe as in the Mediterranean countries, and this is largely linked with the possibilities for effective adaptation to maintain current yields. The most negative effects were found for the continental climate in the Pannonian zone, which includes Hungary, Serbia, Bulgaria and Romania. This region will suffer from increased incidents of heat waves and droughts without possibilities for effectively shifting crop cultivation to other parts of the years. A wide range of adaptation options exists in most European regions to mitigate many of the negative impacts of climate change on crop production in Europe. However, considering all effects of climate change and possibilties for adaptation, impacts are still mostly negative in wide regions across Europe.     

Modelling wheat yield change under CO2 increase,heat and water stress in relation to plant available water capacity in eastern Australia

Increasing heat and water stress are important threats to wheat growth in rain-fed conditions. Using climate scenario-based projections from the Coupled Model Intercomparison Project phase 5 (CMIP5), we analysed changes in the probability of heat stress around wheat flowering and relative yield loss due to water stress at six locations in eastern Australia. As a consequence of warmer average temperatures, wheat flowering occurred earlier, but the probability of heat stress around flowering still increased by about 3.8%–6.2%. Simulated potential yield across six sites increased on average by about 2.5% regardless of the emission scenario. However, simulated water-limited yield tended to decline at wet and cool locations under future climate while increased at warm and dry locations. Soils with higher plant available water capacity (PAWC) showed a lower response of water-limited yield to rainfall changes except at very dry sites, which means soils with high PAWC were less affected by rainfall changes compared with soils with low PAWC. Our results also indicated that a drought stress index decreased with increasing PAWC and then stagnated at high PAWC. Under high emission scenario RCP8.5, drought stress was expected to decline or stay about the same due to elevated CO₂ compensation effect. Therefore, to maintain or increase yield potential in response to the projected climate change, increasing cultivar tolerance to heat stress and improving crop management to reduce impacts of water stress on lower plant available water holding soils should be a priority for the genetic improvement of wheat in eastern Australia.     

气候变化对长江中下游稻区水稻产量的影响

选择长江中下游平原作为研究区域,按照政府间气候变化专业委员会(IPCC)排放情景特别报告(SRES)中的A2和B2方案,将基于区域气候模式PRECIS构建的气候变化情景文件与水稻生长模型ORYZA2000结合,模拟基准时段(1961—1990)气候(Baseline)和2021—2050时段A2、B2情景下的水稻产量,分析未来气候变化对长江中下游水稻产量的影响。构建两种影响评估方法,重点分析增温和大气CO2肥效作用对水稻产量的影响。结果表明,不考虑CO2肥效作用时,随着温度升高,水稻生育期缩短,产量下降。A2情景下水稻生育期平均缩短4.5d,产量减少15.2%;B2情景下平均缩短3.4d,产量减少15%。其中,减产达到20%以上的区域集中在安徽中南部、湖北东南部和湖南东部地区。当考虑CO2肥效作用后,A2情景下水稻平均产量减少5.1%,B2情景平均减少5.8%。减产区域缩小且幅度降低,江西和浙江部分地区则呈现一定程度增产,但增幅10%。大气CO2肥效作用一定程度上可提高水稻产量,使晚稻在增温的不利影响下仍呈现不同程度的增产态势,但对单季稻和早稻的增产贡献仍不足以抵消升温的负面影响。另外,大气CO2肥效作用可有利于提高未来气候变化下水稻的稳产性。     

未来烤烟种植对气候变化的响应与适应模拟

为预测未来气候变化对烤烟产量的影响趋势,借助作物生长模型,结合《排放情景特别报告》(Special Report on Emissions Scenarios,SRES)的2种排放情景A2（强调经济发展）和B2（强调可持续发展）预估的未来气候情景,定量地模拟分析了重庆地区烤烟种植对气候变化的响应与适应。结果表明,种植当前烤烟品种,到2020年,A2情景下,各地烤烟单产波动范围-4.7%~5.7%,增减产幅度不大。巫山、黔江、酉阳、南川等烤烟区仍以轻微增产为主,其余烤烟区为轻度减产区;B2情景下,各地烤烟单产波动范围-35.3%~8.1%,巫山、巫溪、黔江、南川大部等烤烟区以轻微增产为主,其余烤烟区为减产区,其中奉节、武隆烤烟区减产幅度较大,在15%以上。到2040年,A2情景下,各地烤烟区产量波动范围-15.85%~1.93%,除万州烟区轻微增产外,其余烤烟区均为减产区,其中酉阳中部、武隆南部减产幅度较大,在10%以上;B2情景下,各地烤烟区波动范围-14.45%~8.18%,其中,酉阳、彭水与黔江南部为增产区,其余地区烤烟均为减产区。无论是A2情景还是B2情景,重庆大部烤烟区可能会出现不同幅度的减产趋势,且局部减产幅度较大。如果引入适应气候变暖的新品种（模型中只延长烤烟生育后期即开花到顶叶成熟的积温）,A2情景下增产105~170 kg/hm²,增幅6.9%~10.6%;B2情景下增产40~78 kg/hm²,增幅2.5%~5.12%。受气候变暖的影响,由于积温的增加,未来10年内重庆大部地区烤烟会出现不同程度的减产,局地减产严重。如果提前移栽期,通过一些适应对策,如引入适应气候变暖的新品种,可达到很好的增产效果。     

Potential impact of future climate change on sugarcane under dryland conditions in Mexico

Assessments of impacts of future climate change on widely grown sugarcane varieties can guide decision‐making and help ensure the economic stability of numerous rural households. This study assessed the potential impact of future climatic change on sugarcane grown under dryland conditions in Mexico and identified key climate factors influencing yield. The Agricultural Land Management Alternatives with Numerical Assessment Criteria (ALMANAC) model was used to simulate sugarcane growth and yield under current and future climate conditions. Management, soil and climate data from farm sites in Jalisco (Pacific Mexico) and San Luis Potosi (Northeastern Mexico) were used to simulate baseline yields. Baseline climate was developed with 30‐year historical data from weather stations close to the sites. Future climate for three decadal periods (2021–2050) was constructed by adding forecasted climate values from downscaled outputs of global circulation models to baseline values. Climate change impacts were assessed by comparing baseline yields with those in future decades under the A2 scenario. Results indicate positive impacts of future climate change on sugarcane yields in the two regions, with increases of 1%–13% (0.6–8.0 Mg/ha). As seen in the multiple correlation analysis, evapotranspiration explains 77% of the future sugarcane yield in the Pacific Region, while evapotranspiration and number of water and temperature stress days account for 97% of the future yield in the Northeastern Region. The midsummer drought (canicula) in the Pacific Region is expected to be more intense and will reduce above‐ground biomass by 5%–13% (0.5–1.7 Mg/ha) in July–August. Harvest may be advanced by 1–2 months in the two regions to achieve increases in yield and avoid early flowering that could cause sucrose loss of 0.49 Mg ha^?1 month^?1. Integrating the simulation of pest and diseases under climate change in crop modelling may help fine‐tune yield forecasting.     

从农业生态系统承载力看全球生态经济系统前景

本研究运用3种方法预测作物产量潜力,结果表明：（1）利用作物历年单产回归拟合后进行趋势外推,得出多数作物的未来产量潜力极限大约是现在单产的2~3倍;（2）运用“国际应用系统研究所”（IIASA）与“联合国粮农组织”（FAO）共同开发的“农业生态区划”（AEZ）模型计算中国主要粮油作物的区域单产最高潜力,得出水稻、小麦、玉米、马铃薯、油菜和大豆的单产潜力分别是它们2005年全国平均单产的1.2倍、2.2倍、2.2倍、2.9倍、2.0倍、1.9倍;（3）运用自然界中植物的最大光能利用率计算世界主要粮油作物单产的光合潜力,得出水稻、小麦、玉米、马铃薯、油菜、大豆产量的最大光合生产潜力大约分别是目前高产地区单产的1.4倍、2.5倍、1.2倍、1.8倍、1.9倍、2.2倍。据此：从作物产量潜力极限出发,阐述了农业生态系统的承载力;再从“封闭”系统特性出发,论述了全球生态经济系统的不可持续性。     

Participatory design of farm level adaptation to climate risks in an arable region in The Netherlands

In the arable farming region Flevoland in The Netherlands climate change, including extreme events and pests and diseases, will likely pose risks to a variety of crops including high value crops such as seed potato, ware potato and seed onion. A well designed adaptation strategy at the farm level can reduce risks for farmers in Flevoland. Currently, most of the impact assessments rely heavily on (modelling) techniques that cannot take into account extreme events and pests and diseases and cannot address all crops, and are thus not suited as input for a comprehensive adaptation strategy at the farm level.To identify major climate risks and impacts and develop an adaptation measure portfolio for the most relevant risks we complemented crop growth modelling with a semi-quantitative and participatory approach, the Agro Climatic Calendar (ACC), A cost-benefit analysis and stakeholder workshops were used to identify robust adaptation measures and design an adaptation strategy for contrasting scenarios in 2050.For Flevoland, potential yields of main crops were projected to increase, but five main climate risks were identified, and these are likely to offset the positive impacts. Optimized adaptation strategies differ per scenario (frequency of occurrence of climate risks) and per farm (difference in economic loss). When impacts are high (in the +2 °C and A1 SRES scenario) drip irrigation was identified as the best adaptation measure against the main climate risk heat wave that causes second-growth in seed and ware potato. When impacts are smaller (the +1 °C and B2 SRES scenario), other options including no adaptation are more cost-effective.Our study shows that with relatively simple techniques such as the ACC combined with a stakeholder process, adaptation strategies can be designed for whole farming systems. Important benefits of this approach compared to modelling techniques are that all crops can be included, all climate factors can be addressed, and a large range of adaptation measures can be explored. This enhances that the identified adaptation strategies are recognizable and relevant for stakeholders.     

Impacts and adaptation of the cropping systems to climate change in the Northeast Farming Region of China

The Northeast Farming Region of China (NFR) is a very important crop growing area, comprising seven sub-regions: Xing’anling (XA), Sanjiang (SJ), Northwest Songliao (NSL), Central Songliao (CSL), Southwest Songliao (SSL), Changbaishan (CB) and Liaodong (LD), which has been severely affected by extreme climate events and climatic change. Therefore, a set of expert survey has been done to identify current and project future climate limitations to crop production and explore appropriate adaptation measures in NFR. Droughts have been the largest limitation for maize (Zea mays L.) in NSL and SSL, and for soybean (Glycine max L. Merr.) in SSL. Chilling damage has been the largest limitation for rice (Oryza sativa L.) production in XA, SJ and CB. Projected climate change is expected to be beneficial for expanding the crop growing season, and to provide more suitable conditions for sowing and harvest. Autumn frost will occur later in most parts of NFR, and chilling damage will also decrease, particularly for rice production in XA and SJ. Drought and heat stress are expected to become more severe for maize and soybean production in most parts of NFR. Also, plant diseases, pests and weeds are considered to become more severe for crop production under climate change. Adaptation measures that have already been implemented in recent decades to cope with current climatic limitations include changes in timing of cultivation, variety choice, soil tillage practices, crop protection, irrigation and use of plastic film for soil cover. With the projected climate change and increasing risk of climatic extremes, additional adaptation measures will become relevant for sustaining and improving productivity of crops in NFR to ensure food security in China.     

气候变化对中国种植制度影响的研究进展

为研究气候变化对中国农业种植制度的影响,综述了学者们在气候变化对中国种植制度和复种指数影响上的研究结果。结果显示：未来气候变化将会使中国的3熟区面积扩大,1熟区面积缩小,2熟区面积变化较小。农业复种指数在总体增加的情况下,在不同地区的增加幅度有所不同。但是,研究中还存在着气候模型自身的不足以及未考虑技术进步等因素对种植制度和复种指数的影响。因此,在今后的研究中,需要加强模型精确度及多因素综合对中国种植制度的影响研究,以提高预测结果的准确度。     

B2情景对湘鄂双季稻发育期及产量的影响

为保障国家粮食安全、应对气候变化对双季稻生产的影响提供科学依据,利用本地化的作物生长模型分析B2情景下湘鄂双季稻发育期和产量的变化,应用B2情景下逐日气象要素预测值,采用作物生长模型的方法,对2011-2050年气候变化对湘鄂双季稻发育期及产量的影响进行分析。结果表明,在灌溉条件下,2011-2050年湘鄂双季稻全生育期比1961-1990年缩短1~7天,单产比1961-1990年下降5%~12%;其中双季早稻全生育期比1961-1990年缩短1.5~4.5天,单产比1961-1990年下降7%~14%,双季晚稻全生育期比1961-1990年缩短1~3天,单产比1961-1990年下降2%~10%。雨养条件下,2011-2050年双季稻全生育期与灌溉条件下的双季稻全生育期相差不大,但产量降幅较大。2011-2050年湘鄂双季稻单产比灌溉条件下的双季稻下降9%~21%,其中双季早稻下降3%~14%,双季晚稻下降13%~33%。在B2情景下,利用本地化的作物生长模型分析表明,湘鄂双季稻发育期和产量均呈下降趋势,尤其是雨养条件下的双季晚稻,产量下降幅度较大,需积极应对气候变化对湘鄂双季稻生产的影响。     

Comparison of regional climate scenario data by a spatial resolution for the impact assessment of the uncertainty associated with meteorological inputs data on crop yield simulations in Korea

Uncertainty of crop yield simulation would be affected by weather input data prepared from different sources of climate datasets. Although regional climate data at a high spatial resolution would be useful for the impact assessment of climate change on crop production, little effort has been made to characterize the uncertainty associated with such climate data in terms of crop yield simulations. The objectives of this study were to compare climate scenario data products obtained from a series of downscaling processes and to identify an overall pattern of uncertainty in these climate data in terms of crop yield simulation. Regional climate scenario data from 2011 to 2014 had a spatiotemporal pattern of uncertainty, which differed by meteorological variables and spatial resolution. Overall, the uncertainty of daily minimum temperature was greater than that of maximum temperature. Daily minimum temperature also had relatively greater uncertainty in an early season of crop production, which could result in the cumulative impact on the uncertainty of crop yield simulations. For the uncertainty of climate data at different spatial resolution, climate data at higher spatial resolution, e.g. 1 km, tended to have lower uncertainty than data at resolution of 12.5 km did. Still, the uncertainty of regional climate data was relatively similar between data at resolution of 12.5 km and 1 km in major rice production areas in Korea except in areas near Seosan. This merits further studies to examine actual differences in projected crop yields using regional climate scenario data in the future and to assess the impact of uncertainty associated with regional climate data on crop yield simulation.     

Implications of climate model biases and downscaling on crop model simulated climate change impacts

In estimating responses of crops to future climate realisations, it is necessary to understand and differentiate sources of uncertainty. This paper considers the specific aspect of input weather data quality from a Regional Climate Model (RCM) leading to differences in estimates made by three crop models. The availability of hindcast RCM estimates enables comparison of crop model outputs derived from observed and modelled weather data. Errors in estimating the past climate implies biases in future projections, and thus affect modelled crop responses. We investigate the complexities in using climate model projections representing different spatial scales within climate change impacts and adaptation studies. This is illustrated by simulating spring barley with three crop models run using site-specific observed (12 UK sites), original (50 × 50 km) and bias corrected downscaled (site-specific) hindcast (1960–1990) weather data from the HadRM3 RCM. Though the bias correction downscaling method improved the match between observed and hindcast data, this did not always translate into better matching of crop model estimates. At four sites the original HadRM3 data produced near identical mean simulated yield values as from the observed weather data, despite evaluated (observed-hindcast) differences. This is likely due to compensating errors in the input weather data and non-linearity in the crop models processes, making interpretation of results problematic. Understanding how biases in climate data manifest themselves in individual crop models gives greater confidence in the utility of the estimates produced using downscaled future climate projections and crop model ensembles. The results have implications on how future projections of climate change impacts are interpreted. Fundamentally, considerable care is required in determining the impact weather data sources have in climate change impact and adaptation studies, whether from individual models or ensembles.     

Adaptation to climate change and climate variability in European agriculture: The importance of farm level responses

Climatic conditions and hence climate change influence agriculture. Most studies that addressed the vulnerability of agriculture to climate change have focused on potential impacts without considering adaptation. When adaptation strategies are considered, socio-economic conditions and farm management are often ignored, but these strongly influence current farm performance and are likely to also influence adaptation to future changes. This study analysed the adaptation of farmers and regions in the European Union to prevailing climatic conditions, climate change and climate variability in the last decades (1990–2003) in the context of other conditions and changes. We compared (1) responses in crop yields with responses in farmers’ income, (2) responses to spatial climate variability with responses to temporal climate variability, (3) farm level responses with regional level responses and (4) potential climate impacts (based on crop models) with actual climate impacts (based on farm accountancy data). Results indicated that impacts on crop yields cannot directly be translated to impacts on farmers’ income, as farmers adapt by changing crop rotations and inputs. Secondly, the impacts of climatic conditions on spatial variability in crop yields and farmers’ income, with generally lower yields in warmer climates, is different from the impacts of temporal variability in climate, for which more heterogeneous patterns are observed across regions in Europe. Thirdly, actual impacts of climate change and variability are largely dependent on farm characteristics (e.g. intensity, size, land use), which influence management and adaptation. To accurately understand impacts and adaptation, assessments should consider responses at different levels of organization. As different farm types adapt differently, a larger diversity in farm types reduces impacts of climate variability at regional level, but certain farm types may still be vulnerable. Lastly, we observed that management and adaptation can largely reduce the potential impacts of climate change and climate variability on crop yields and farmers’ income. We conclude that for reliable projections of the impacts of climate change on agriculture, adaptation should not be seen anymore as a last step in a vulnerability assessment, but as integrated part of the models used to simulate crop yields, farmers’ income and other indicators related to agricultural performance.     

气候变化背景下陕西关中西部作物气候生产潜力变化特征

为了研究气候变化背景下关中西部作物气候生产潜力变化规律,选用宝鸡市11个气象站1961—2010年温度、降水等气象资料,应用Tuynthwhite Memoral模式计算分析宝鸡地区作物气候生产力状况及其变化趋势。结果表明：关中西部气候生产力呈递减趋势;年及各季平均气温均呈明显上升趋势,降水量呈下降趋势;气候暖干化使作物气候生产潜力以35.69 kg/(hm²·10 a)的速率波动下降,降水是主要限制因子;气候生产力利用率平均为34.8%,作物生产有较大的发展潜力;未来气候情景下,“暖湿型”气候对区域作物生产最有利,平均增产幅度8.5%~22.5%,而“冷干型”气候对作物生产最不利,平均减产幅度为5.7%~20.8%。     

Consequences of climate change for European agricultural productivity, land use and policy

This paper reviews the knowledge on effects of climate change on agricultural productivity in Europe and the consequences for policy and research. Warming is expected to lead to a northward expansion of suitable cropping areas and a reduction of the growing period of determinate crops (e.g. cereals), but an increase for indeterminate crops (e.g. root crops). Increasing atmospheric CO₂ concentrations will directly enhance plant productivity and also increase resource use efficiencies.

In northern areas climate change may produce positive effects on agriculture through introduction of new crop species and varieties, higher crop production and expansion of suitable areas for crop cultivation. Disadvantages may be an increase in the need for plant protection, the risk of nutrient leaching and the turnover of soil organic matter. In southern areas the disadvantages will predominate. The possible increase in water shortage and extreme weather events may cause lower harvestable yields, higher yield variability and a reduction in suitable areas for traditional crops. These effects may reinforce the current trends of intensification of agriculture in northern and western Europe and extensification in the Mediterranean and southeastern parts of Europe.

Policy will have to support the adaptation of European agriculture to climate change by encouraging the flexibility of land use, crop production, farming systems etc. In doing so, it is necessary to consider the multifunctional role of agriculture, and to strike a variable balance between economic, environmental and social functions in different European regions. Policy will also need to be concerned with agricultural strategies to mitigate climate change through a reduction in emissions of methane and nitrous oxide, an increase in carbon sequestration in agricultural soils and the growing of energy crops to substitute fossil energy use. The policies to support adaptation and mitigation to climate change will need to be linked closely to the development of agri-environmental schemes in the European Union Common Agricultural Policy.

Research will have further to deal with the effect on secondary factors of agricultural production, on the quality of crop and animal production, of changes in frequency of isolated and extreme weather events on agricultural production, and the interaction with the surrounding natural ecosystems. There is also a need to study combined effects of adaptation and mitigation strategies, and include assessments of the consequences on current efforts in agricultural policy to develop a sustainable agriculture that also preserves environmental and social values in the rural society.