The long-term goal of the 2015 Paris Agreement is to limit global warming to well below 2 ℃above pre-industrial levels and to pursue efforts to limit it to 1.5 ℃. However, for climate mitigation and adaption efforts...The long-term goal of the 2015 Paris Agreement is to limit global warming to well below 2 ℃above pre-industrial levels and to pursue efforts to limit it to 1.5 ℃. However, for climate mitigation and adaption efforts, further studies are still needed to understand the regional consequences between the two global warming limits. Here we provide an assessment of changes in temperature extremes over China （relative to 1986-2005） at 1.5 ℃ and 2 ℃ warming levels （relative to 1861-1900） by using the 5th phase of the Coupled Model Intercomparison Project （CMIP5） models under three RCP scenarios （RCP2.6, RCP4.5, RCP8.5）. Results show that the increases in mean temperature and temperature extremes over China are greater than that in global mean temperature. With respect to 1986-2005, the temperature of hottest day （TXx） and coldest night （TNn） are projected to increase about 1/1.6 ℃ and 1.1/1.8 ℃, whereas warm days （TX90p） and warm spell duration （WSDI） will increase about 7.5/13.8% and 15/30 d for the 1.5/2 ℃ global warming target, respectively. Under an additional 0.5 ℃ global warming, the projected increases of temperature in warmest day/night and coldest day/night are both more than 0.5 ℃ across almost the whole China. In Northwest China, Northeast China and the Tibetan Plateau, the projected changes are particularly sensitive to the additional 0.5 ℃ global warming, for example, multi-model mean increase in coldest day （TXn） and coldest night （TNn） will be about 2 times higher than a change of 0.5 ℃ global warming. Although the area-averaged changes in temperature extremes are very similar for different scenarios, spatial hotspot still exists, such as in Northwest China and North China, the increases in temperatures are apparently larger in RCP8.5 than that in RCP4.5.展开更多
《巴黎协定》提出全球暖化程度在21世纪末相对工业革命前控制在2℃以内的目标。青藏高原高寒植被对全球变暖非常敏感,在2℃温升这个边界增温条件下研究高原植被对气候变化的响应关系到高原生态安全问题,有重大现实意义。本文基于CMIP5...《巴黎协定》提出全球暖化程度在21世纪末相对工业革命前控制在2℃以内的目标。青藏高原高寒植被对全球变暖非常敏感,在2℃温升这个边界增温条件下研究高原植被对气候变化的响应关系到高原生态安全问题,有重大现实意义。本文基于CMIP5多模式模拟预测结果研究了高原植被对2℃温升的响应,并探讨了高原植被对于气候因子变化的敏感性,得到主要结论如下:在全球2℃温升背景下,高原植被叶面积指数(Leaf Area Index, LAI)较历史参考期显著增加,高原变绿,其中高原中部LAI和植被碳存储增加最为显著,三江源是植被LAI增加较快的区域。增温后裸地面积迅速减少,植被覆盖率总体增加,大部分地区草地呈增加趋势,森林减少趋势变缓,说明在2℃温升期高原植被有所改善。在全球2℃温升背景下,高原植被覆盖率表现出对温度和降水率等气候因子更强的依赖性和敏感性,在增暖环境中,气温仍是影响高原植被生态系统变化的主控因子。展开更多
Based on LMDZ4 daily temperature dataset,equidistant cumulative distribution function matching method(EDCDFm)and cumulative distribution function-transform method(CDF-t)are used to evaluate the ability of models in si...Based on LMDZ4 daily temperature dataset,equidistant cumulative distribution function matching method(EDCDFm)and cumulative distribution function-transform method(CDF-t)are used to evaluate the ability of models in simulating extreme temperature over central and eastern China.The future temperature change is then projected.The results show that the EDCDFm and CDF-t methods function effectively correct the spatial distribution of daily mean temperature and extreme temperature,significantly reduce the biases of the model simulation and effectively improve the capacity of models for spatial pattern of extreme temperature.However,the cold bias of the CDF-t method in winter is obviously higher than that of the EDCDFm method,and the temperature change curve of the EDCDFm method is closer to the observation than that of the CDF-t method.The projection based on the EDCDFm method shows that under the RCP4.5 emission scenario,the temperature in the study area shows a warming trend.Relative to 1986e2005,the mean temperature is projected to increase by 0.76,1.84,and 2.10℃during 2017e2036,2046e2065,and 2080e2099,respectively.The spatial change for the mean,maximum,and minimum temperature in the three future periods have good consistency;warming in northern China is higher than that in the south.Uncertainties in temperature projection are large in the Tibetan Plateau and Sichuan Basin.Frost days decrease significantly,especially in the Tibetan Plateau,and the frost days in the three periods decrease by more than 15,30,and 40 d,respectively.The variation of heat wave indice is the smallest;the increase of heat wave is mainly in eastern China,and the increase in South China is more than 2 d.Besides,under the global warming of 1.5℃and 2℃,the response characteristics of extreme temperature over central and eastern China are also analyzed.The results show that the mean temperature,maximum temperature and minimum temperature in the study area increase by more than 0.75℃under 1.5℃target and over 1.25℃under 2℃target,especially in the northwestern China and the Tibetan Plateau,relative to 1986e2005.Additionally,comparing two warming targets,the difference of three temperature indices in parts of northeastern China is over 1.5℃,while more than 3 d for heat wave.展开更多
The global environment is changing with increasing temperature and atmospheric carbon dioxide concentration. Because the two factors are concomitant and the rise of global carbon dioxide concentration will affect all ...The global environment is changing with increasing temperature and atmospheric carbon dioxide concentration. Because the two factors are concomitant and the rise of global carbon dioxide concentration will affect all biomass across the full global range of temperatures, we review the theory regarding and observations on the effects of temperature and carbon dioxide concentration interactions onplant carbon balance, growth, development, biomass accumulation and yield. Although there are sound theoretical reasons for expecting a large stimulation of net CO 2 assimilation rates by increased \[CO 2 \] at higher temperatures, this does not necessarily mean that the pattern of biomass and yield responses to increasing \[CO 2 \] and temperature are determined by this response. This paper reviews the interactions between the effects of \[CO 2 \] and different temperatures on plants. There is little unequivocal evidence for large differences in response to \[CO 2 \] at different temperatures, as studies are confounded by the different responses of the species adapted and acclimated to different temperatures, and the interspecific difference in growth form and development pattern. It is coueluded that stress we should the importance of initiation and expansion of meristems and organs and the balance between assimilate supply and sink activity in determining the growth response to increasing \[CO 2 \] and temperature. Tab 1 , Ref展开更多
The Paris Agreement aims to keep global warming to well below 2℃ above pre-industrial levels and to pursue efforts to limit it to 1.5℃,recognizing this will reduce the risks of natural disasters significantly.As cha...The Paris Agreement aims to keep global warming to well below 2℃ above pre-industrial levels and to pursue efforts to limit it to 1.5℃,recognizing this will reduce the risks of natural disasters significantly.As changes in the risks of temperature extremes are often associated with changes in the temperature probability distribution,further analysis is still needed to improve understanding of the warm extremes over China.In this study,changes in the occurrence probability of temperature extremes and statistic characteristics of the temperature distribution are investigated using the fifth phase of the Coupled Model Intercomparison Project(CMIP5)multimodel simulations from 1861 to 2100.The risks of the once-in-100-year TXx and TNx events are projected to increase by 14.4 and 31.4 times at 1.5℃ warming.Even,the corresponding risks under 2℃ global warming are 23.3 and 50.6,implying that the once-in-100-year TXx and TNx events are expected to occur about every 5 and 2 years over China,respectively.The Tibetan Plateau,Northwest China and south of the Yangtze River are in greater risks suffering hot extremes(both day and night extremes).Changes in the occurrence probability of warm extremes are generally well explained by the combination of the shifts in location and scale parameters in areas with grown variability,i.e.,the Tibetan Plateau for TXx,south of the Yangtze River for both TXx and TNx.The location(scale)parameter leading the risks of once-in-20-year TXx to increase by more than 5(0.25)and 3(0.75)times under 2℃ warming in the Tibetan Plateau and south of the Yangtze River,respectively.The location parameter is more important for regions with decreased variability e.g.,the Tibetan Plateau for TNx,Northwest China for both TXx and TNx,with risks increase by more than 3,6 and 4 times due to changes in location.展开更多
采用T-FACE(Temperature-free air carbon dioxide enrichment)试验平台,设置田间常规温度和CO_(2)浓度(CK)、田间常规温度和增加CO_(2)浓度至575μmol·L^(-1)(C)、升高温度(高于大气温度2℃)和田间常规CO_(2)浓度(T)以及升高温度...采用T-FACE(Temperature-free air carbon dioxide enrichment)试验平台,设置田间常规温度和CO_(2)浓度(CK)、田间常规温度和增加CO_(2)浓度至575μmol·L^(-1)(C)、升高温度(高于大气温度2℃)和田间常规CO_(2)浓度(T)以及升高温度(高于大气温度2℃)和增加CO_(2)浓度至575μmol·L^(-1)(CT)共4个处理,对田间冬小麦进行控制实验。在小麦播种期、越冬期、分蘖期和成熟期分别采集不同层次的土壤样品(耕作层0-14cm、犁底层14-33cm、潴育层33-59cm和潜育层59-80cm),分析大气CO_(2)浓度增加和温度升高后农田土壤N、P含量及其有效性的动态变化,以揭示气候变化对农田土壤中养分含量的时空影响。结果表明:(1)冬小麦在越冬期CO_(2)浓度增加的情况下,常规或升高温度可使潴育层土壤中硝态氮含量出现下降趋势,在越冬期除T处理外,CK、C和CT处理的硝态氮含量在播种期低于耕作层。在越冬期的各处理中,硝态氮含量以CK处理增加最为明显。(2)在增加CO_(2)浓度和升高温度的情况下,耕作层土壤中铵态氮含量在越冬期和分蘖期显著低于田间正常的CO_(2)浓度和温度处理,且在不同土壤层次中未表现出明显的上升或下降的现象;铵态氮含量在小麦整个生长期相对稳定,但CT、C和T三种不同处理条件下,小麦成熟期铵态氮含量明显增加,且温度升高处理下的增加趋势显著(P<0.05);在小麦整个生育期内,C处理下铵态氮表现出先上升后下降的趋势,而CK、CT和T处理则表现出上升—下降—上升的趋势。(3)小麦全生育期内CK处理的速效磷含量明显高于其它处理,且在播种期、越冬期和分蘖期,CK处理与CT和T处理速效磷含量差异显著(P<0.05)。未来气候变化引起的CO_(2)浓度增加和温度升高情况下,应合理施用N、P肥,减少不必要的养分流失。展开更多
One-year-old seedlings of Pinus koraiensis, Pinus sylvestriformis, Phellodendron amurense were grown in open-top chambers (OTCs) with 700 and 500 (mol/mol CO2 concentrations, control chamber and on open site (ambient ...One-year-old seedlings of Pinus koraiensis, Pinus sylvestriformis, Phellodendron amurense were grown in open-top chambers (OTCs) with 700 and 500 (mol/mol CO2 concentrations, control chamber and on open site (ambient CO2, about 350 (mol/mol CO2) respectively at the Open Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences, and the growth course responses of three species to elevated CO2 and temperature during one growing season was studied from May to Oct. 1999. The results showed that increase in CO2 concentration enhanced the growth of seedlings and the effect of 700 (mol/mol CO2 was more remarkable than 500 (mol/mol CO2 on seedling growth. Under the condition of doubly elevated CO2 concentration, the biomass increased by 38% in average for coniferous seedlings and 60% for broad-leaved seedlings. With continuous treatment of high CO2 concentration, the monthly-accumulated biomass of shade-tolerant Pinus koraiensis seedlings was bigger in July than in August and September, while those of Pinus sylvestriformis and Phellodendron amurense seedlings showed an increase in July and August, or did not decrese until September. During the hot August, high CO2 concentration enhanced the growth of Pinus koraiensis seedlings by increasing temperature, but it did not show dominance in other two species.展开更多
基金We acknowledge the World Climate Research Programme＇s Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the climate modeling groups （listed in Table l） for producing and making available their model output. This research is supported by the National Key Research and Development Program of China （2017YFA0603804） and the State Key Program of National Natural Science Foundation of China （41230528）.
文摘The long-term goal of the 2015 Paris Agreement is to limit global warming to well below 2 ℃above pre-industrial levels and to pursue efforts to limit it to 1.5 ℃. However, for climate mitigation and adaption efforts, further studies are still needed to understand the regional consequences between the two global warming limits. Here we provide an assessment of changes in temperature extremes over China （relative to 1986-2005） at 1.5 ℃ and 2 ℃ warming levels （relative to 1861-1900） by using the 5th phase of the Coupled Model Intercomparison Project （CMIP5） models under three RCP scenarios （RCP2.6, RCP4.5, RCP8.5）. Results show that the increases in mean temperature and temperature extremes over China are greater than that in global mean temperature. With respect to 1986-2005, the temperature of hottest day （TXx） and coldest night （TNn） are projected to increase about 1/1.6 ℃ and 1.1/1.8 ℃, whereas warm days （TX90p） and warm spell duration （WSDI） will increase about 7.5/13.8% and 15/30 d for the 1.5/2 ℃ global warming target, respectively. Under an additional 0.5 ℃ global warming, the projected increases of temperature in warmest day/night and coldest day/night are both more than 0.5 ℃ across almost the whole China. In Northwest China, Northeast China and the Tibetan Plateau, the projected changes are particularly sensitive to the additional 0.5 ℃ global warming, for example, multi-model mean increase in coldest day （TXn） and coldest night （TNn） will be about 2 times higher than a change of 0.5 ℃ global warming. Although the area-averaged changes in temperature extremes are very similar for different scenarios, spatial hotspot still exists, such as in Northwest China and North China, the increases in temperatures are apparently larger in RCP8.5 than that in RCP4.5.
文摘《巴黎协定》提出全球暖化程度在21世纪末相对工业革命前控制在2℃以内的目标。青藏高原高寒植被对全球变暖非常敏感,在2℃温升这个边界增温条件下研究高原植被对气候变化的响应关系到高原生态安全问题,有重大现实意义。本文基于CMIP5多模式模拟预测结果研究了高原植被对2℃温升的响应,并探讨了高原植被对于气候因子变化的敏感性,得到主要结论如下:在全球2℃温升背景下,高原植被叶面积指数(Leaf Area Index, LAI)较历史参考期显著增加,高原变绿,其中高原中部LAI和植被碳存储增加最为显著,三江源是植被LAI增加较快的区域。增温后裸地面积迅速减少,植被覆盖率总体增加,大部分地区草地呈增加趋势,森林减少趋势变缓,说明在2℃温升期高原植被有所改善。在全球2℃温升背景下,高原植被覆盖率表现出对温度和降水率等气候因子更强的依赖性和敏感性,在增暖环境中,气温仍是影响高原植被生态系统变化的主控因子。
基金Funding for this study was provided by the National Key R&D Program of China(2017YFA0603804)and the National Natural Science Foundation of China(41230528).
文摘Based on LMDZ4 daily temperature dataset,equidistant cumulative distribution function matching method(EDCDFm)and cumulative distribution function-transform method(CDF-t)are used to evaluate the ability of models in simulating extreme temperature over central and eastern China.The future temperature change is then projected.The results show that the EDCDFm and CDF-t methods function effectively correct the spatial distribution of daily mean temperature and extreme temperature,significantly reduce the biases of the model simulation and effectively improve the capacity of models for spatial pattern of extreme temperature.However,the cold bias of the CDF-t method in winter is obviously higher than that of the EDCDFm method,and the temperature change curve of the EDCDFm method is closer to the observation than that of the CDF-t method.The projection based on the EDCDFm method shows that under the RCP4.5 emission scenario,the temperature in the study area shows a warming trend.Relative to 1986e2005,the mean temperature is projected to increase by 0.76,1.84,and 2.10℃during 2017e2036,2046e2065,and 2080e2099,respectively.The spatial change for the mean,maximum,and minimum temperature in the three future periods have good consistency;warming in northern China is higher than that in the south.Uncertainties in temperature projection are large in the Tibetan Plateau and Sichuan Basin.Frost days decrease significantly,especially in the Tibetan Plateau,and the frost days in the three periods decrease by more than 15,30,and 40 d,respectively.The variation of heat wave indice is the smallest;the increase of heat wave is mainly in eastern China,and the increase in South China is more than 2 d.Besides,under the global warming of 1.5℃and 2℃,the response characteristics of extreme temperature over central and eastern China are also analyzed.The results show that the mean temperature,maximum temperature and minimum temperature in the study area increase by more than 0.75℃under 1.5℃target and over 1.25℃under 2℃target,especially in the northwestern China and the Tibetan Plateau,relative to 1986e2005.Additionally,comparing two warming targets,the difference of three temperature indices in parts of northeastern China is over 1.5℃,while more than 3 d for heat wave.
文摘The global environment is changing with increasing temperature and atmospheric carbon dioxide concentration. Because the two factors are concomitant and the rise of global carbon dioxide concentration will affect all biomass across the full global range of temperatures, we review the theory regarding and observations on the effects of temperature and carbon dioxide concentration interactions onplant carbon balance, growth, development, biomass accumulation and yield. Although there are sound theoretical reasons for expecting a large stimulation of net CO 2 assimilation rates by increased \[CO 2 \] at higher temperatures, this does not necessarily mean that the pattern of biomass and yield responses to increasing \[CO 2 \] and temperature are determined by this response. This paper reviews the interactions between the effects of \[CO 2 \] and different temperatures on plants. There is little unequivocal evidence for large differences in response to \[CO 2 \] at different temperatures, as studies are confounded by the different responses of the species adapted and acclimated to different temperatures, and the interspecific difference in growth form and development pattern. It is coueluded that stress we should the importance of initiation and expansion of meristems and organs and the balance between assimilate supply and sink activity in determining the growth response to increasing \[CO 2 \] and temperature. Tab 1 , Ref
基金supported by the National Key Research and Development Program of China(2017YFA0603804 and 2016YFA0600402).
文摘The Paris Agreement aims to keep global warming to well below 2℃ above pre-industrial levels and to pursue efforts to limit it to 1.5℃,recognizing this will reduce the risks of natural disasters significantly.As changes in the risks of temperature extremes are often associated with changes in the temperature probability distribution,further analysis is still needed to improve understanding of the warm extremes over China.In this study,changes in the occurrence probability of temperature extremes and statistic characteristics of the temperature distribution are investigated using the fifth phase of the Coupled Model Intercomparison Project(CMIP5)multimodel simulations from 1861 to 2100.The risks of the once-in-100-year TXx and TNx events are projected to increase by 14.4 and 31.4 times at 1.5℃ warming.Even,the corresponding risks under 2℃ global warming are 23.3 and 50.6,implying that the once-in-100-year TXx and TNx events are expected to occur about every 5 and 2 years over China,respectively.The Tibetan Plateau,Northwest China and south of the Yangtze River are in greater risks suffering hot extremes(both day and night extremes).Changes in the occurrence probability of warm extremes are generally well explained by the combination of the shifts in location and scale parameters in areas with grown variability,i.e.,the Tibetan Plateau for TXx,south of the Yangtze River for both TXx and TNx.The location(scale)parameter leading the risks of once-in-20-year TXx to increase by more than 5(0.25)and 3(0.75)times under 2℃ warming in the Tibetan Plateau and south of the Yangtze River,respectively.The location parameter is more important for regions with decreased variability e.g.,the Tibetan Plateau for TNx,Northwest China for both TXx and TNx,with risks increase by more than 3,6 and 4 times due to changes in location.
文摘采用T-FACE(Temperature-free air carbon dioxide enrichment)试验平台,设置田间常规温度和CO_(2)浓度(CK)、田间常规温度和增加CO_(2)浓度至575μmol·L^(-1)(C)、升高温度(高于大气温度2℃)和田间常规CO_(2)浓度(T)以及升高温度(高于大气温度2℃)和增加CO_(2)浓度至575μmol·L^(-1)(CT)共4个处理,对田间冬小麦进行控制实验。在小麦播种期、越冬期、分蘖期和成熟期分别采集不同层次的土壤样品(耕作层0-14cm、犁底层14-33cm、潴育层33-59cm和潜育层59-80cm),分析大气CO_(2)浓度增加和温度升高后农田土壤N、P含量及其有效性的动态变化,以揭示气候变化对农田土壤中养分含量的时空影响。结果表明:(1)冬小麦在越冬期CO_(2)浓度增加的情况下,常规或升高温度可使潴育层土壤中硝态氮含量出现下降趋势,在越冬期除T处理外,CK、C和CT处理的硝态氮含量在播种期低于耕作层。在越冬期的各处理中,硝态氮含量以CK处理增加最为明显。(2)在增加CO_(2)浓度和升高温度的情况下,耕作层土壤中铵态氮含量在越冬期和分蘖期显著低于田间正常的CO_(2)浓度和温度处理,且在不同土壤层次中未表现出明显的上升或下降的现象;铵态氮含量在小麦整个生长期相对稳定,但CT、C和T三种不同处理条件下,小麦成熟期铵态氮含量明显增加,且温度升高处理下的增加趋势显著(P<0.05);在小麦整个生育期内,C处理下铵态氮表现出先上升后下降的趋势,而CK、CT和T处理则表现出上升—下降—上升的趋势。(3)小麦全生育期内CK处理的速效磷含量明显高于其它处理,且在播种期、越冬期和分蘖期,CK处理与CT和T处理速效磷含量差异显著(P<0.05)。未来气候变化引起的CO_(2)浓度增加和温度升高情况下,应合理施用N、P肥,减少不必要的养分流失。
基金Chinese Academy of Sciences and the Open Research Station of Changbai Mountain Forest Ecosystem.
文摘One-year-old seedlings of Pinus koraiensis, Pinus sylvestriformis, Phellodendron amurense were grown in open-top chambers (OTCs) with 700 and 500 (mol/mol CO2 concentrations, control chamber and on open site (ambient CO2, about 350 (mol/mol CO2) respectively at the Open Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences, and the growth course responses of three species to elevated CO2 and temperature during one growing season was studied from May to Oct. 1999. The results showed that increase in CO2 concentration enhanced the growth of seedlings and the effect of 700 (mol/mol CO2 was more remarkable than 500 (mol/mol CO2 on seedling growth. Under the condition of doubly elevated CO2 concentration, the biomass increased by 38% in average for coniferous seedlings and 60% for broad-leaved seedlings. With continuous treatment of high CO2 concentration, the monthly-accumulated biomass of shade-tolerant Pinus koraiensis seedlings was bigger in July than in August and September, while those of Pinus sylvestriformis and Phellodendron amurense seedlings showed an increase in July and August, or did not decrese until September. During the hot August, high CO2 concentration enhanced the growth of Pinus koraiensis seedlings by increasing temperature, but it did not show dominance in other two species.
