A2 Greenhouse Gas Emission Scenario Research Articles

气候变化对淮河流域中上游汛期极端流量影响的SWAT模拟

PDF HTML阅读 XML下载 导出引用 引用提醒 气候变化对淮河流域中上游汛期极端流量影响的SWAT模拟 DOI: 10.5846/stxb201609281957 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（41475062）；国家重大基础研究计划（2010CB428506）；水利部公益性行业科研项目（200901042，200901024）；福建省教育厅B类项目（JB12016）水利部公益性行业科研项目（200901042，200901024） Effects of climate change on extreme streamflow in flood season in the upper and middle basin of the Huaihe River by SWAT simulation Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:致洪暴雨主要是3天以上连续强降水，是淮河流域洪涝的直接原因。构建淮河流域中上游SWAT模型，用RegCM3在SRES A2排放情景下的模拟结果（2071-2100年）驱动SWAT模型，研究气候变化对淮河流域中上游汛期极端流量的影响。结果表明：（1）在SRES A2排放情景下，淮河流域中上游未来（2071-2100年）气温升高，降水量增加，降水的空间差异增大；颖河流域中游年降水量有较大幅度的减少，呈现暖干化的趋势；汛期极端过程降水增加，汛期最大9 d降水量平均增幅都在10%以上。（2）在SRES A2排放情景下的气候变化将导致淮河流域中上游汛期极端流量大幅度增加，干流5个水文站汛期最大9 d平均流量的增幅都在20%以上。（3）淮河流域中上游极端流量的概率分布更加集中，更大的极端流量出现的频率更高，研究流域下游更容易出现较大的极端流量。（4）研究流域下游极端流量概率对极端流量变化更敏感，下游也面临着更大的洪涝风险。 Abstract:Consecutive rainstorm events are a main flash-flood-producing phenomenon on a basin scale, and an extreme consecutive rainstorm is more likely to cause catastrophic floods in the Huaihe River Basin. We constructed a SWAT model for the upper and middle basin of the Huaihe River and the drove model using the RegCM3 outputs under SRES A2 Greenhouse Gas Emission Scenarios, during the period from January 1, 2071 to December 31, 2100, to investigate the extreme streamflow response to the climate change during the flood seasons. First, we analyzed the relationship between the maximum 3-13 day precipitation amount and the maximum 3-13 day mean streamflow and determined the maximum 9 day precipitation amount as an indicator of the extreme consecutive rainstorm and the maximum 9-day mean streamflow as an indicator of the extreme streamflow in the flood season. Second, we constructed a SWAT model for the upper and middle basin of the Huaihe River to simulate the maximum 9-day mean streamflow in the flood season. Thirdly, we drove the model using the RegCM3 outputs and simulated the maximum 9-day mean streamflow during the period from January 1, 2071 to December 31, 2100, under SRES A2 Greenhouse Gas Emission Scenarios and the period from January 1,1961 to December 31, 1990 (reference period) respectively. Finally, we compared the results of the maximum 9-day mean streamflow in the flood season under two climate scenarios, and investigated the response of the extreme flow to climate change from the perspective of the probability characteristics. The SWAT model constructed for the upper and middle basin of the Huaihe River simulated monthly streamflow accurately based on the observational data during the period from 1958 to 2009. Simultaneously, the simulation results also reproduced the prominent characteristics of the maximum 9-day mean streamflow in the flood season. The results indicated that, under SRES A2 Scenarios, during the period from January 1, 2071 to December 31, 2100:(1) RegCM3 predicted that annual mean temperature will rise, annual precipitation amount will increase, and the spatial contrast of precipitation will increase in the upper and middle basin of the Huaihe River. However, the annual precipitation amount decreased in the middle basin of the Yinghe River and showed a warming and drying trend. Simultaneously, extreme consecutive precipitation in the flood season increased, especially in the southern basin of the lower reaches. (2) The extreme streamflow in the flood season increased more remarkably, and the maximum 9-day mean streamflow in the flood season increased more than 20% on average in five hydrological gauges. (3) The probability distribution of extreme streamflow was more concentrated and the frequency of the extreme streamflow was much higher, with much higher flood risk in the middle and lower basin. (4) The probability of extreme streamflow in the lower basin responded more sensitively to the extreme streamflow changes, which means flood risks increase owing to climate change. These conclusions have practical significance for flood risk management and control in the Huaihe River Basin under the climate change scenario. 参考文献 相似文献 引证文献

Impact of climate change on urban heat island effect and extreme temperatures: a case‐study

This study investigated the impacts of climate change on the urban heat island (UHI) and the number of very hot (maximum temperature >35°C) and very cold days (minimum temperature <5°C) in the central business district (CBD) of Melbourne city in Australia. A station located in Laverton (less urbanised area), which is 17 km southwest of Melbourne CBD, was selected as the reference station for the computation of UHI intensity in Melbourne CBD. Using daily minimum/maximum temperatures at the two stations, nocturnal/diurnal UHI intensities in Melbourne CBD were computed for the period 1952–2010. It was found that in Melbourne CBD, nocturnal UHI intensities show a clear rising trend over the period 1952–2010 unlike the diurnal UHI intensities. For the analysis of nocturnal UHI intensities in Melbourne CBD, under changing climate, for each calendar month statistical models based on the gene expression programming (GEP) technique were developed for downscaling general‐circulation model (GCM) outputs to monthly average minimum temperature at Melbourne CBD and Laverton. Using the outputs of HadCM3, GFDL2.0 and ECHAM5 pertaining to the A2 greenhouse gas emission scenario on the downscaling models, projections of monthly average minimum temperature were produced for the two stations over the period 2000–2099. In each season, at both stations, the ensemble average of monthly minimum temperature gradually increased over the period 2000–2099. The ensemble‐average UHI intensity in Melbourne CBD projected into the future was higher for all seasons in comparison to that of period 1952–1971. Downscaling models based on the GEP technique were developed for each calendar month for projecting the number of very hot days in November–March and very cold days in May–September in Melbourne CBD. It was found that, in the future, summer weather will spread to early autumn, and winter weather will move to early spring, in Melbourne CBD.

Extreme summer heat in Phoenix, Arizona (USA) under global climate change (2041-2070)

Summer extreme heat events in the arid Phoenix, Arizona (USA) metropolitan region for the period 2041-2070 are projected based on the ensemble of ten climate models from the North American Regional Climate Change Assessment Program for the SRES A2 greenhouse gas emissions scenario by the Intergovernmental Panel on Climate Change. Extreme heat events are identified by measures related to two thresholds of the maximum daily air temperature distribution for the historical reference period 1971-2000. Comparing this reference period to the model ensemble-mean, the frequency of extreme heat events is projected to increase by a factor of six to 1.9 events per summer and the average number of event days per year is projected to increase by a factor of 14. The inter-model range for the average number of EHE days per summer is larger for the projected climate, 10.6 to 42.2 days, than for simulations of the past climate simulations (1.5 to 2.4 days).

Hydropower Reservoir Management Under Climate Change: The Karoon Reservoir System

This study assesses the performance of hydropower production by reservoirs with and without climate change impacts on river discharge. The case study of this research includes the Khersan 1, Karoon 4, and Karoon 3 reservoirs in Iran. The HADCM3 climate model with A2 greenhouse gas emission scenario is coupled with proportional downscaling to assess the impact of climate change on river discharge and reservoir hydropower production. The IHACRES rainfall- runoff model is implemented for calculating river discharge under climate-change conditions. Reservoir simulation and optimization models are implemented to calculate hydropower production in the base period (1986–2000), future period 1 (2025–2039), future period 2 (2055–2069), and future period 3 (2085–2099). The power production and performance criteria of the reservoirs are calculated using simulation (standard operating policy) and optimization models in the considered periods. Our results show that the largest reductions of reservoir discharge correspond, in decreasing order, to the future periods 3, 1, and 2, respectively. Moreover, the hydropower production obtained with the optimization model is found to be larger than that obtained with the simulation model. The calculated increase in power production in the base period and future periods 1, 2, and 3 is equal to 6, 19, 10, and 22 %, respectively. These results demonstrate the benefit of applying optimization modeling for hydropower production in the Khersan -Karoon reservoir system to mitigate and adapt to climate-change impacts on river discharge.

A watershed-scale study of climate change impacts on groundwater recharge (Annapolis Valley, Nova Scotia, Canada)

The potential impacts of future climate change on the evolution of groundwater recharge are examined at a local scale for a 546-km2 watershed in eastern Canada. Recharge is estimated using the infiltration model Hydrologic Evaluation of Landfill Performance (HELP), with inputs derived from five climate runs generated by a regional climate model in combination with the A2 greenhouse gas emissions scenario. The model runs project an increase in annual recharge over the 2041–2070 period. On a seasonal basis, however, a marked decrease in recharge during the summer and a marked increase during the winter are observed. The results suggest that increased evapotranspiration resulting from higher temperatures does not offset the large increase in winter infiltration. In terms of individual water budget components, clear differences are obtained for the different climate change scenarios. Monthly recharge values are also found to be quite variable, even for a given climate scenario. These findings are compared with results from two regional-scale studies.Editor D. Koutsoyiannis; Associate editor M. BesbesCitation Rivard, C., Paniconi, C., Vigneault, H., and Chaumont, D., 2014. A watershed-scale study of climate change impacts on groundwater recharge (Annapolis Valley, Nova Scotia, Canada). Hydrological Sciences Journal, 59 (8), 1437–1456. http://dx.doi.org/10.1080/02626667.2014.887203

Climate change may have limited effect on global risk of potato late blight

Weather affects the severity of many plant diseases, and climate change is likely to alter the patterns of crop disease severity. Evaluating possible future patterns can help focus crop breeding and disease management research. We examined the global effect of climate change on potato late blight, the disease that caused the Irish potato famine and still is a common potato disease around the world. We used a metamodel and considered three global climate models for the A2 greenhouse gas emission scenario for three 20-year time-slices: 2000-2019, 2040-2059 and 2080-2099. In addition to global analyses, five regions were evaluated where potato is an important crop: the Andean Highlands, Indo-Gangetic Plain and Himalayan Highlands, Southeast Asian Highlands, Ethiopian Highlands, and Lake Kivu Highlands in Sub-Saharan Africa. We found that the average global risk of potato late blight increases initially, when compared with historic climate data, and then declines as planting dates shift to cooler seasons. Risk in the agro-ecosystems analyzed, varied from a large increase in risk in the Lake Kivu Highlands in Rwanda to decreases in the Southeast Asian Highlands of Indonesia.

Temperature Extremes from Canadian Regional Climate Model (CRCM) Climate Change Projections

Future climate projections of extreme events can help forewarn society of high-impact events and allow the development of better adaptation strategies. In this study a non-stationary model for Generalized Extreme Value (GEV) distributions is used to analyze the trend in extreme temperatures in the context of a changing climate and compare it with the trend in average temperatures.The analysis is performed using the climate projections of the Canadian Regional Climate Model (CRCM), under an IPCC SRES A2 greenhouse gas emissions scenario, over North America. Annual extremes in daily minimum and maximum temperatures are analyzed. Significant positive trends for the location parameter of the GEV distribution are found, indicating an expected increase in extreme temperature values. The scale parameter of the GEV distribution, on the other hand, reveals a decrease in the variability of temperature extremes in some continental regions. Trends in the annual minimum and maximum temperatures are compared with trends in average winter and summer temperatures, respectively. In some regions, extreme temperatures exhibit a significantly larger increase than the seasonal average temperatures.The CRCM projections are compared with those of its driving model and framed in the context of the Coupled Model Intercomparison Project, phase 3 (CMIP3) Global Climate Model projections. This enables us to establish the CRCM position within the CMIP3 climate projection uncertainty range. The CRCM is validated against the HadEX2 dataset in order to assess the CRCM representation of temperature extremes in the present climate. The validation is also framed in the context of CMIP3 validation results. The CRCM cold extremes validate better and are closer to the driving model and CMIP3 projections than the hot extremes.

Simulating effects of land use policies on extent of the wildland urban interface and wildfire risk in Flathead County, Montana

This study used a wildfire loss simulation model to evaluate how different land use policies are likely to influence wildfire risk in the wildland urban interface (WUI) for Flathead County, Montana. The model accounts for the complex socio-ecological interactions among climate change, economic growth, land use change and policy, homeowner mitigations, and forest treatments in Flathead County's WUI over the five 10-year subperiods comprising the future evaluation period (i.e., 2010–2059). Wildfire risk, defined as expected residential losses from wildfire [E(RLW)], depends on the number of residential properties on parcels, the probability that parcels burn, the probability of wildfire losses to residential structures on properties given the parcels on which those properties are located burn, the average percentage of wildfire-related losses in aesthetic values of residential properties, and the total value (structures plus land) of residential properties. E(RLW) for the five subperiods is simulated for 2010 (referred to as the current), moderately restrictive, and highly restrictive land use policy scenarios, a moderate economic growth scenario and the A2 greenhouse gas emissions scenario. Results demonstrate that increasingly restrictive land use policy for Flathead County significantly reduces the amount and footprint of future residential development in the WUI. In addition, shifting from the current to a moderately restrictive land use policy for Flathead County significantly reduces wildfire risk for the WUI, but shifting from the current to a highly restrictive land use policy does not significantly reduce wildfire risk in the WUI. Both the methods and results of the study can help land and wildfire managers to better manage future wildfire risk and identify residential areas having potentially high wildfire risk.

Spatially-explicit assessment of flood risk caused by climate change in South Korea

Identifying spatially-explicit risk is essential for efficient flood management with limited resources and budgets. We investigated national-scale relative flood risk for 139 sub-basins in South Korea under current and future climate conditions. A non-parametric index method was employed to calculate relative flood risk based on a sensitivity index, an exposure index, and an adaptive capacity index for each sub-basin. A dynamically downscaled climate simulation based on the A2 Greenhouse Gas (GHG) emission scenario, provided by the Korean Meteorological Research Institute (METRI), was used to examine possible change in flood risk. The estimated flood risk generally agreed with historical flood damage. The highly vulnerable sub-basins had high exposure indices, reflecting frequent heavy rainfall, as well as high sensitivity indices due to dense population at low elevation. Although rainfall intensity and frequency is likely to increase under the A2 GHG emission scenario, the spatial pattern of relative flood risk did not change remarkably. Our results indicate that reducing flood sensitivity levels and enhancing the adaptive capacity in vulnerable regions will be critical aspects of climate change preparation in South Korea.

Global dynamical projections of surface ocean wave climate for a future high greenhouse gas emission scenario

A global 1° implementation of the spectral wave model, WaveWatch III, was forced with surface winds from two atmosphere–ocean general circulation models (AOGCMs: ECHAM5 and CSIRO Mk3.5), dynamically downscaled to 60km using the Cubic Conformal Atmospheric Model. Two 30-yr time slices were simulated: 1979–2009 representing current climate, and 2070–2099 representing a future climate scenario under a high greenhouse gas emission scenario (SRES A2). A further wave model simulation with forcing from the NCEP Climate Forecast System Reanalysis for 1979–2009, using the same model settings as the climate model forced runs, serves as a benchmark hindcast to assess skill of climate-model-derived wave fields. Climate model forced wave simulations for the 1979–2009 time-slice display biases relative to the benchmark wave climate – notably an overestimation of wave generation in the Southern Ocean, which influences broad regions of the Pacific which receive these waves as swell. Wave model runs were repeated following bias-adjustment of the climate model forcing winds with the aim to reduce biases, but model skill to simulate the monthly 99th percentile of significant wave heights deteriorates severely.Projected future changes in wave climate (between 1979–2009 and 2070–2099) under the SRES A2 greenhouse gas emission scenario are relatively insensitive to whether bias-adjustment of winds has been applied. Two robust features of projected change are observed from the two climate model sets which are qualitatively consistent with previous studies: a projected increase of Southern Ocean wave generation leading to approximately 10% increase in Southern Ocean mean significant wave heights (HSm), and a projected decrease in wave generation in the North Atlantic, with changes in HSm of similar magnitude.Interannual anomalies of monthly mean significant wave height, HSm, were regressed against climate indices (Southern Oscillation Index – SOI; North Atlantic Oscillation – NAO and the Southern Annular Mode – SAM) over each time-slice. Significant differences in the relationships between wave height variability and these climate indices between current and projected climates are observed. For example, a significant shift from negative to positive correlation between the NAO and HSm anomalies along the western European and north-west African coasts in the projected future climate is noted. The potential future changes in wind-wave characteristics, and the changing relationships between interannual variability of wave climate with identified climate indices, as a response to projected future climate scenarios have broad implications for a range of processes and activities in the coastal, near-and-off-shore environments.

Modelling runoff in a Swiss glacierized catchment—Part II: daily discharge and glacier evolution in the Findelen basin in a progressively warmer climate

AbstractIn the context of global warming, hydrological regimes in mountain areas are likely to be modified and will therefore result in significant impacts to the supply mechanisms for hydropower and other end‐uses of water, both in the mountains themselves and in the lowland regions downstream. The main objective here is to attempt a fine and continuous analysis of the impacts of such changes on runoff and glaciers in a largely ice‐covered catchment in the Swiss Alps: the Findelen watershed. The simulated daily discharge values have been obtained with a semi‐distributed hydrological model called Routing System 3 (RS3.0). A stochastic weather generator has been used to generate a 110 year sequence of meteorological input data—described in a companion article—that have been further perturbed in order to simulate a progressively warmer climate by the end of the century. The amplitude of atmospheric change is suggested by regional climate model simulations, under the A2 greenhouse‐gas emissions scenario. Results show at first an increase of discharge (19.4% in about 60 years) due to the rapid melt of the glacier, followed by a large decrease in runoff at the end of the period (−28% from the beginning to the end of the studied timeframe), primarily due to the depletion of the solid water reservoir. The glacier is indeed projected to lose 91% of its surface area. In parallel, a seasonal shift in flow patterns is also observed: the discharge values are high earlier in spring due to advanced snow and ice melt, while the rest of the curve flattens out. Copyright © 2012 Royal Meteorological Society

Assessment of future stream flow over the Sesan catchment of the Lower Mekong Basin in Vietnam

AbstractThis study used a regional climate model, driven at a resolution of 30 km, to derive climate estimates that were used as input to a hydrological model to determine stream flow in a changing climate. This regional climate model output was derived using the Weather Research and Forecasting model, which was used to downscale the general circulation model ECHAM5 T63 under the A2 greenhouse gas emission scenario for the future. Two river basins, Dakbla and Poko, over the Sesan catchment of the Lower Mekong region were considered for runoff modeling. A 10‐year climatology of the recent past, 1991–2000, was used as the baseline for the present‐day climate, and another 10‐year climate over the period 2091–2100 was chosen for the future time slice. The results from the simulation of future stream flow indicate that, over both Dakbla and Poko river basins, the stream flow is likely to increase, especially during the peak rainfall season. The Dakbla River Basin shows a substantial increase in stream flow when compared with the Poko River Basin. Copyright © 2011 John Wiley & Sons, Ltd.

IMPACT OF CLIMATE CHANGE ON HEAT RELATED MORTALITY AND MORBIDITY IN EUROPE

Background and Aims: Public health concerns about the health effects of extreme temperatures have risen because of the intense heatwaves of 2003 and 2006 in Europe. Climate change projections indicate that average temperatures are rising and that the intensity, frequency, and duration of extreme heat events will increase. As a part of the Climate-TRAP project we used emission scenarios, models and epidemiological data to assess heat related health impacts under a changing climate. Methods: Gridded climate data were obtained as a 50x50km grid for Europe using two global climate models (HADCM3 and ECHAM4) regionally downscaled over Europe with the RCA3. Modelled temperature and humidity data for the time periods 1961-1990 and 2021-2050 was used to represent the recent and future climatic conditions. Data for the A1B and A2 greenhouse gas emission scenarios (modelled with HADCM3 and ECHAM4 respectively) were used to illustrate possible outcomes for different climate scenarios. We used exposure response functions determined for a number of European cities within the PHEWE-project. Results: Future temperatures are predicted to increase the expected annual mortality for Europe in 2021-2050 compared to 1961–1990 by 1.15% and 1.28% for the A1B and the A2 scenarios, respectively. The increase differs between countries, with a range from no increase in heat-related mortality for the Baltic countries to increases above 3% for Spain, Slovenia and Portugal. For hospital admissions, the expected increase is substantially lower than the estimations for mortality with increases ranging up to 0.66% in Spain. Conclusions: This study suggest that the expected annual increase in heat related mortality in 2021-2050 compared to 1961– 1990 in Europe is in the same order of magnitude as the excess number of heat related deaths during the 2003 heatwave over Europe.

Climate Change, Atmospheric Rivers, and Floods in California - A Multimodel Analysis of Storm Frequency and Magnitude Changes1

Dettinger, Michael, 2011. Climate Change, Atmospheric Rivers, and Floods in California – A Multimodel Analysis of Storm Frequency and Magnitude Changes. Journal of the American Water Resources Association (JAWRA) 47(3):514-523. DOI: 10.1111/j.1752-1688.2011.00546.x Abstract: Recent studies have documented the important role that “atmospheric rivers” (ARs) of concentrated near-surface water vapor above the Pacific Ocean play in the storms and floods in California, Oregon, and Washington. By delivering large masses of warm, moist air (sometimes directly from the Tropics), ARs establish conditions for the kinds of high snowlines and copious orographic rainfall that have caused the largest historical storms. In many California rivers, essentially all major historical floods have been associated with AR storms. As an example of the kinds of storm changes that may influence future flood frequencies, the occurrence of such storms in historical observations and in a 7-model ensemble of historical-climate and projected future climate simulations is evaluated. Under an A2 greenhouse-gas emissions scenario (with emissions accelerating throughout the 21st Century), average AR statistics do not change much in most climate models; however, extremes change notably. Years with many AR episodes increase, ARs with higher-than-historical water-vapor transport rates increase, and AR storm-temperatures increase. Furthermore, the peak season within which most ARs occur is commonly projected to lengthen, extending the flood-hazard season. All of these tendencies could increase opportunities for both more frequent and more severe floods in California under projected climate changes.

Effects of projected changes in tropical cyclone frequency on sea turtles

Tropical cyclones are amongst the world’s most destructive natural hazards and can negatively affect sea turtles by disturbing their foraging and nesting habitats, increasing localised mortality of their eggs, and potentially skewing hatchling sex ratios towards females. Cyclonic frequency, intensity, distribution and seasonality are predicted to alter with climate change. This will influence both the effects of cyclones on the nesting grounds and reproductive output of sea turtles and the frequency with which these nesting grounds are hit by cyclones. However, only a few studies have investigated how future cyclonic activity will affect turtle populations. Studies conducted to date have concentrated on how projected intensification of cyclonic activity will affect sea turtles and have found that intensification of cyclones will reduce hatching success at sea turtle nesting grounds. No study to date has, however, considered or investigated how the predicted changes in cyclone frequency and distribution may affect sea turtle populations. Here, we used climate change models and turtle life history information to predict how projected changes in the frequency of cyclones will affect 4 sea turtle species: green turtle Chelonia mydas, flatback turtle Natator depresus, hawksbill turtle Eretmochelys imbricata and loggerhead turtle Caretta caretta, nesting on the eastern Australian (Queensland) coast. To account for known variability in model projections of cyclonic activity, we used 11 regional climate model simulations for an A2 greenhouse gas emission scenario for conditions predicted for 2055 and 2090. The model projections indicated a tendency towards a reduction in cyclonic activity at the studied nesting grounds in the future and, thus, a decrease in the effects on sea turtle nesting along the Queensland coast.

Impact of global warming on streamflow drought in Europe

Recent developments in climate modeling suggest that global warming is likely to favor conditions for the development of droughts in many regions of Europe. Studies evaluating possible changes in drought hazard typically have employed indices that are derived solely from climate variables such as temperature and precipitation, whereas many of the impacts of droughts are more related to hydrological variables such as river flow. This study examines the impact of global warming on streamflow drought in Europe by comparing low‐flow predictions of a hydrological model driven by high‐resolution regional climate simulations for the end of the previous century and for the end of this century based on the Special Report on Emissions Scenarios A2 greenhouse gas emission scenario. For both time slices, low‐flow characteristics were derived from the simulated streamflow series using extreme value analysis. More specifically, we employed the methods of block maxima and partial duration series to obtain minimum flows and flow deficits and fitted extreme value distributions by the maximum likelihood method. In order not to mix drought events with different physical causes the analysis was performed separately for the frost and nonfrost season. Results show that in the frost‐free season streamflow droughts will become more severe and persistent in most parts of Europe by the end of this century, except in the most northern and northeastern regions. In the frost season, streamflow drought conditions will be of less importance under future climate conditions.

Sensitivity of winter chill models for fruit and nut trees to climatic changes expected in California's Central Valley

Many fruit and nut crops require cold temperatures in winter to break dormancy. Quantifying this chilling requirement and selecting appropriate cultivars for the climate of a growing region is crucial for successful cultivation of such crops. Several models exist to quantify winter chill, and each growing region uses a model that has been shown to perform well under local climatic conditions. We tested the sensitivity of four commonly used chilling models to projected climatic change likely to affect fruit and nut production in the near future. For six sites in California's Central Valley, we generated 100 years of synthetic hourly weather records, representing climatic conditions in 1950, 2000 and projected temperatures in 2041–2060 derived from three IPCC-AR4 General Circulation Models (GCMs; CSIRO, HadCM3 and MIROC; A2 greenhouse gas emissions scenario). Mean winter chill for each site and year was calculated using the Chilling Hours, Utah, Positive Utah and Dynamic models. All chilling models predicted substantial decreases in winter chill at all sites, but the extent of these decreases varied depending on the model used. Across all sites between 1950 and 2050, mean chilling was predicted to decrease by 33% (Chilling Hours), 26% (Utah Model), 16% (Dynamic Model) and 14% (Positive Utah Model). Research efforts are needed to identify the most appropriate chilling model for preparing fruit and nut growers for the imminent effects of climate change.

Adaptation to Climate Change in the Management of a Canadian Water-Resources System Exploited for Hydropower

The management adaptation potential of the Peribonka River water resource system (Quebec, Canada) is investigated in the context of the evolution of climate change. The objective of this study is to evaluate the impacts on hydropower, power plant efficiency, unproductive spills and reservoir reliability due to changes in the hydrological regimes. The climate change projections used here are from the Canadian regional climate model (CRCM) nested by the Canadian-coupled global climate model (CGCM3) forced with the SRES A2 greenhouse gas emission scenario. The hydrological regimes were simulated with the distributed hydrological model Hydrotel. They were incorporated into a dynamic and stochastic optimization model in order to adapt the operating rules of the water resource system annually, according to the evolution of the climate. The impacts were analyzed over the years 1961–2099, split into four periods for comparison purposes: control period (1961–1990), horizon 2020 (2010–2039), horizon 2050 (2040–2069) and horizon 2080 (2070–2099). The main results indicate that annual mean hydropower would decrease by 1.8% for the period 2010–2039 and then increase by 9.3% and 18.3% during the periods 2040–2069 and 2070–2099, respectively. The trend to increase is statistically significant starting from 2061 (Mann–Kendall with p = 5%). The change in the mean annual production is statistically significant for the 2040–2069 and 2070–2099 periods (t-test with p = 5%). Also, the change in the variance is significant for the periods 2010–2039, 2040–2069 and 2070–2099 (F-test). Annual mean unproductive spills would increase from 1961–2099, but the trend is not statistically significant. However, the changes in the variance of the annual mean spills are significant in the periods 2010–2039, 2040–2069 and 2070–2099. Overall, the reliability of a reservoir would decrease and the vulnerability increase as the climate changes.

Extreme heat reduces and shifts United States premium wine production in the 21st century

Premium wine production is limited to regions climatically conducive to growing grapes with balanced composition and varietal typicity. Three central climatic conditions are required: (i) adequate heat accumulation; (ii) low risk of severe frost damage; and (iii) the absence of extreme heat. Although wine production is possible in an extensive climatic range, the highest-quality wines require a delicate balance among these three conditions. Although historical and projected average temperature changes are known to influence global wine quality, the potential future response of wine-producing regions to spatially heterogeneous changes in extreme events is largely unknown. Here, by using a high-resolution regional climate model forced by the Intergovernmental Panel on Climate Change Special Report on Emission Scenarios A2 greenhouse gas emission scenario, we estimate that potential premium winegrape production area in the conterminous United States could decline by up to 81% by the late 21st century. While increases in heat accumulation will shift wine production to warmer climate varieties and/or lower-quality wines, and frost constraints will be reduced, increases in the frequency of extreme hot days (>35 degrees C) in the growing season are projected to eliminate winegrape production in many areas of the United States. Furthermore, grape and wine production will likely be restricted to a narrow West Coast region and the Northwest and Northeast, areas currently facing challenges related to excess moisture. Our results not only imply large changes for the premium wine industry, but also highlight the importance of incorporating fine-scale processes and extreme events in climate-change impact studies.