The onset,cessation,and length of the rainy season are crucial for global water resources,agricultural practices,and food security.However,the response of precipitation seasonality to global warming remains uncertain....The onset,cessation,and length of the rainy season are crucial for global water resources,agricultural practices,and food security.However,the response of precipitation seasonality to global warming remains uncertain.In this study,we analyze how global warming levels(GWLs)of 1.5℃ and 2℃ could affect the timing of rainfall onset(RODs),rainfall cessation(RCDs),and the overall duration of the rainy season(LRS)over global land monsoon(GLM)regions using simulations from CMIP6 under the SSP2-4.5 and SSP5-8.5 scenarios.With high model consensus,our results reveal that RODs are projected to occur later over Southern Africa,North Africa,and South America,but earlier over South Asia and Australia,in a warmer climate.The projected early RODs in Australia are more pronounced at the 2℃ GWL under SSP5-8.5.On the other hand,early RCDs are projected over South America and East Asia,while late RCDs are projected over North Africa,with high inter-model agreement.These changes are associated with a future decrease in LRS in most GLM regions.Additionally,we found that continuous warming over 1.5℃ will further reduce the length of the rainy season,especially over the South America,North Africa,and Southern Africa monsoon regions.The findings underscore the urgent need to mitigate global warming.展开更多
High temperature warning indicators play a pivotal role in meteorological departments,serving as crucial criteria for issuing warnings that guide both social production and daily life.Despite their importance,limited ...High temperature warning indicators play a pivotal role in meteorological departments,serving as crucial criteria for issuing warnings that guide both social production and daily life.Despite their importance,limited studies have explored the relationship between different global warming levels and changes in high temperature warning indicators.In this study,we analyze data from 2,419 meteorological stations over China and utilize the Coupled Model Intercomparison Project Phase 6(CMIP6)models to examine historical changes in high temperature warning indicators used by the China Meteorological Administration.We evaluate model performance and estimate future changes in these indicators using an annual cycle bias correction method.The results indicate that since 1961,the number of high temperature days(TX35d and TX40d)and length of season(TX40d and TX40l)with daily maximum temperature reaching or exceeding 35℃ and 40℃ have increased over China.The intensity of high temperatures(TXx)has strengthened and the geographical extent affected by high temperatures has expanded.In 2022,the occurrence of 40℃ high temperatures surges,with Eastern China experiencing a two-day increase in TX40d and an extended seasonal length in TX40l by over five days.While CMIP6 models have underestimated the high temperature indictors associated with 35℃ during historical periods,notable difference is not observed between the models and observations for TX40d and TX40l,given their rare occurrence.However,future projections,after bias correction,indicate that the increasing trends for 35℃ and 40℃ high temperature days and length of season become more pronounced than the raw projection,suggesting a more severe increase than that anticipated originally.As global warming intensifies,the high temperature days and length of season are projected to increase non-linearly,while the intensity of high temperatures is expected to increase linearly.For every 1℃ increase in global temperature,the intensity is projected to rise by approximately 1.4℃.The impact of high temperatures is expanding,with the major hotspot for China located in the eastern and northwestern regions.Under 5℃ global warming,certain regions in China may experience prolonged extreme high temperatures.For instance,40℃ high temperature days in areas like North China and the Yangtze River Basin could increase by about 32 d,and the length of season could extend by approximately 100 d.展开更多
Aims the impacts of future global warming of 1.5℃ and 2℃ on the productivity and carbon(c)storage of grasslands in china are not clear yet,although grasslands in china support~45 million agricultural populations and...Aims the impacts of future global warming of 1.5℃ and 2℃ on the productivity and carbon(c)storage of grasslands in china are not clear yet,although grasslands in china support~45 million agricultural populations and more than 238 million livestock populations,and are sensitive to global warming.Methods this study used a process-based terrestrial ecosystem model named ORcHIDEE to simulate c cycle of alpine meadows and temperate grasslands in china.this model was driven by high-resolution(0.5°×0.5°)climate of global specific warming levels(SWL)of 1.5℃ and 2℃(warmer than pre-industrial level),which is downscaled by Ec-EARtH3-HR v3.1 with sea surface temperature and sea-ice concentration as boundary conditions from IPSL-cM5-LR(low spatial resolution,2.5°×1.5°)Earth system model(ESM).Important Findingscompared with baseline(1971-2005),the mean annual air temperature over chinese grasslands increased by 2.5℃ and 3.7℃ under SWL1.5 and SWL2,respectively.the increase in temperature in the alpine meadow was higher than that in the temperate grassland under both SWL1.5 and SWL2.Precipitation was also shown an increasing trend under SWL2 over most of the chinese grasslands.Strong increases in gross primary productivity(GPP)were simulated in the chinese grasslands,and the mean annual GPP(GPP_(MA))increased by 19.32%and 43.62%under SWL1.5 and SWL2,respectively.the c storage increased by 0.64 Pg c and 1.37 Pg c under SWL1.5 and SWL2 for 50 years simulations.the GPP_(MA) was 0.67_(0.39)^(0.88)(0.82)(model mean_(min) ^(max) (this study)),0.85_(0.45)^(1.24)(0.97)and 0.94_(0.61)^(1.30)(1.17)Pg C year^(−1) under baseline,SWL1.5 and SWL2 modeled by four cMIP5 ESMs(phase 5 of the coupled Model Inter-comparison Project Earth System Models).In contrast,the mean annual net biome productivity was−18.55_(−40.37)^(4.47)(−3.61),18.65_(−2.03)^(64.03)(10.29)and 24.15_(8.38)^(38.77)(24.93)Tg C year^(−1) under base-line,SWL1.5 and SWL2 modeled by the four cMIP5 ESMs.Our results indicated that the chinese grasslands would have higher productivity than the baseline and can mitigate climate change through increased C sequestration under future global warming of 1.5℃ and 2℃ with the increase of precipitation and the global increase of atmospheric CO_(2) concentration.展开更多
No studies have examined the effect of experimental warming on the microbial biomass and community composition of soil in agricultural ecosystem on the Qinghai-Tibet Plateau. Thus it is unclear whether the influences ...No studies have examined the effect of experimental warming on the microbial biomass and community composition of soil in agricultural ecosystem on the Qinghai-Tibet Plateau. Thus it is unclear whether the influences of experimental warming on microbial communities in soil are related to warming magnitude in croplands on this Plateau. This study performed warming experiment(control, low-and high-level) in a highland barley system of the Lhasa River in May 2014 to examine the correlation between the response of microbial communities in soil to warming and warming magnitude. Topsoil samples(0–10 and 10–20 cm) were collected on September 14, 2014. Experimental warming at both low and high levels significantly increased soil temperature by 1.02 ℃ and 1.59 ℃, respectively at the depth of 15 cm. Phospho lipid fatty acid(PLFA) method was used to determine the microbial community in soil. The low-level experimental warming did not significantly affect the soil’s total PLFA, fungi, bacteria, arbuscular mycorrhizal fungi(AMF), actinomycetes, gram-positive bacteria(G+), gram-negative bacteria(G–), protozoa, the ratio of fungi to bacteria(F/B ratio), and ratio of G+ to G–(G+/G– ratio) at the 0–10 and 10–20 cm depth. The low-level experimental warming also did not significantly alter the composition of microbial community in soil at the 0–10 and 10–20 cm depth. The high-level experimental warming significantly increased total PLFA by 74.4%, fungi by 78.0%, bacteria by 74.0%, AMF by 66.9%, actinomycetes by 81.4%, G+ by 67.0% and G– by 74.4% at the 0–10 cm depth rather than at 10–20 cm depth. The high-level experimental warming significantly altered microbial community composition in soil at the 0–10 cm depth rather than at 10-20 cm depth. Our findings suggest that the response of microbial communities in soil to warming varied with warming magnitudes in the highland barley system of the Lhasa River.展开更多
基金supported by the Australian Research Council(Grant No.CE230100012)。
文摘The onset,cessation,and length of the rainy season are crucial for global water resources,agricultural practices,and food security.However,the response of precipitation seasonality to global warming remains uncertain.In this study,we analyze how global warming levels(GWLs)of 1.5℃ and 2℃ could affect the timing of rainfall onset(RODs),rainfall cessation(RCDs),and the overall duration of the rainy season(LRS)over global land monsoon(GLM)regions using simulations from CMIP6 under the SSP2-4.5 and SSP5-8.5 scenarios.With high model consensus,our results reveal that RODs are projected to occur later over Southern Africa,North Africa,and South America,but earlier over South Asia and Australia,in a warmer climate.The projected early RODs in Australia are more pronounced at the 2℃ GWL under SSP5-8.5.On the other hand,early RCDs are projected over South America and East Asia,while late RCDs are projected over North Africa,with high inter-model agreement.These changes are associated with a future decrease in LRS in most GLM regions.Additionally,we found that continuous warming over 1.5℃ will further reduce the length of the rainy season,especially over the South America,North Africa,and Southern Africa monsoon regions.The findings underscore the urgent need to mitigate global warming.
基金supported by the National Natural Science Foundation of China(Grant Nos.42025503&U2342228)the Key Innovation Team of China Meteorological Administration Climate Change Detection and Response(Grant No.CMA2022ZD03)。
文摘High temperature warning indicators play a pivotal role in meteorological departments,serving as crucial criteria for issuing warnings that guide both social production and daily life.Despite their importance,limited studies have explored the relationship between different global warming levels and changes in high temperature warning indicators.In this study,we analyze data from 2,419 meteorological stations over China and utilize the Coupled Model Intercomparison Project Phase 6(CMIP6)models to examine historical changes in high temperature warning indicators used by the China Meteorological Administration.We evaluate model performance and estimate future changes in these indicators using an annual cycle bias correction method.The results indicate that since 1961,the number of high temperature days(TX35d and TX40d)and length of season(TX40d and TX40l)with daily maximum temperature reaching or exceeding 35℃ and 40℃ have increased over China.The intensity of high temperatures(TXx)has strengthened and the geographical extent affected by high temperatures has expanded.In 2022,the occurrence of 40℃ high temperatures surges,with Eastern China experiencing a two-day increase in TX40d and an extended seasonal length in TX40l by over five days.While CMIP6 models have underestimated the high temperature indictors associated with 35℃ during historical periods,notable difference is not observed between the models and observations for TX40d and TX40l,given their rare occurrence.However,future projections,after bias correction,indicate that the increasing trends for 35℃ and 40℃ high temperature days and length of season become more pronounced than the raw projection,suggesting a more severe increase than that anticipated originally.As global warming intensifies,the high temperature days and length of season are projected to increase non-linearly,while the intensity of high temperatures is expected to increase linearly.For every 1℃ increase in global temperature,the intensity is projected to rise by approximately 1.4℃.The impact of high temperatures is expanding,with the major hotspot for China located in the eastern and northwestern regions.Under 5℃ global warming,certain regions in China may experience prolonged extreme high temperatures.For instance,40℃ high temperature days in areas like North China and the Yangtze River Basin could increase by about 32 d,and the length of season could extend by approximately 100 d.
基金This study was supported by the National Key Research and Development Program of China(grant no.2016YFA0600202 and 2016YFC0500203)National Basic Research Program of China(grant no.2013CB956303).
文摘Aims the impacts of future global warming of 1.5℃ and 2℃ on the productivity and carbon(c)storage of grasslands in china are not clear yet,although grasslands in china support~45 million agricultural populations and more than 238 million livestock populations,and are sensitive to global warming.Methods this study used a process-based terrestrial ecosystem model named ORcHIDEE to simulate c cycle of alpine meadows and temperate grasslands in china.this model was driven by high-resolution(0.5°×0.5°)climate of global specific warming levels(SWL)of 1.5℃ and 2℃(warmer than pre-industrial level),which is downscaled by Ec-EARtH3-HR v3.1 with sea surface temperature and sea-ice concentration as boundary conditions from IPSL-cM5-LR(low spatial resolution,2.5°×1.5°)Earth system model(ESM).Important Findingscompared with baseline(1971-2005),the mean annual air temperature over chinese grasslands increased by 2.5℃ and 3.7℃ under SWL1.5 and SWL2,respectively.the increase in temperature in the alpine meadow was higher than that in the temperate grassland under both SWL1.5 and SWL2.Precipitation was also shown an increasing trend under SWL2 over most of the chinese grasslands.Strong increases in gross primary productivity(GPP)were simulated in the chinese grasslands,and the mean annual GPP(GPP_(MA))increased by 19.32%and 43.62%under SWL1.5 and SWL2,respectively.the c storage increased by 0.64 Pg c and 1.37 Pg c under SWL1.5 and SWL2 for 50 years simulations.the GPP_(MA) was 0.67_(0.39)^(0.88)(0.82)(model mean_(min) ^(max) (this study)),0.85_(0.45)^(1.24)(0.97)and 0.94_(0.61)^(1.30)(1.17)Pg C year^(−1) under baseline,SWL1.5 and SWL2 modeled by four cMIP5 ESMs(phase 5 of the coupled Model Inter-comparison Project Earth System Models).In contrast,the mean annual net biome productivity was−18.55_(−40.37)^(4.47)(−3.61),18.65_(−2.03)^(64.03)(10.29)and 24.15_(8.38)^(38.77)(24.93)Tg C year^(−1) under base-line,SWL1.5 and SWL2 modeled by the four cMIP5 ESMs.Our results indicated that the chinese grasslands would have higher productivity than the baseline and can mitigate climate change through increased C sequestration under future global warming of 1.5℃ and 2℃ with the increase of precipitation and the global increase of atmospheric CO_(2) concentration.
基金National Natural Science Foundation of China(31370458,31600432,41807331)Bingwei Outstanding Young Talents Program of Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences(2018RC202)+2 种基金National Key Research Projects of China(2016YFC0502005,2016YFC0502006,2017YFA0604801)Youth Innovation Research Team Project of Key Laboratory of Ecosystem Network Observation and Modeling(LENOM2016Q0002)Tibet Science and Technology Major Projects of Pratacultural Industry(XZ201801NA02)
文摘No studies have examined the effect of experimental warming on the microbial biomass and community composition of soil in agricultural ecosystem on the Qinghai-Tibet Plateau. Thus it is unclear whether the influences of experimental warming on microbial communities in soil are related to warming magnitude in croplands on this Plateau. This study performed warming experiment(control, low-and high-level) in a highland barley system of the Lhasa River in May 2014 to examine the correlation between the response of microbial communities in soil to warming and warming magnitude. Topsoil samples(0–10 and 10–20 cm) were collected on September 14, 2014. Experimental warming at both low and high levels significantly increased soil temperature by 1.02 ℃ and 1.59 ℃, respectively at the depth of 15 cm. Phospho lipid fatty acid(PLFA) method was used to determine the microbial community in soil. The low-level experimental warming did not significantly affect the soil’s total PLFA, fungi, bacteria, arbuscular mycorrhizal fungi(AMF), actinomycetes, gram-positive bacteria(G+), gram-negative bacteria(G–), protozoa, the ratio of fungi to bacteria(F/B ratio), and ratio of G+ to G–(G+/G– ratio) at the 0–10 and 10–20 cm depth. The low-level experimental warming also did not significantly alter the composition of microbial community in soil at the 0–10 and 10–20 cm depth. The high-level experimental warming significantly increased total PLFA by 74.4%, fungi by 78.0%, bacteria by 74.0%, AMF by 66.9%, actinomycetes by 81.4%, G+ by 67.0% and G– by 74.4% at the 0–10 cm depth rather than at 10–20 cm depth. The high-level experimental warming significantly altered microbial community composition in soil at the 0–10 cm depth rather than at 10-20 cm depth. Our findings suggest that the response of microbial communities in soil to warming varied with warming magnitudes in the highland barley system of the Lhasa River.
