A model-by-model analysis for historical simulations was necessary for identifying reasonably performing models in the updated Coupled Model Intercomparison Project(CMIP6)over the Tibetan Plateau.To determine whether ...A model-by-model analysis for historical simulations was necessary for identifying reasonably performing models in the updated Coupled Model Intercomparison Project(CMIP6)over the Tibetan Plateau.To determine whether the capacity of the CMIP6 models in simulating temperature and precipitation over the Plateau has been enhanced,we compared the outputs of 23 CMIP6 models with an observational dataset(CN05.1)for the period 1961–2014.The results suggest the systematic model biases(cold bias and wet bias)in the Tibetan Plateau still exist in CMIP6.Most models in CMIP6 realistically simulated the surface temperature and spatial distribution of precipitation,with a pattern correlation exceeding 0.75.The bias in the mean surface temperature of the multi-model ensemble(MME)simulation was 1.08℃ lower than the observational data,which had been decreased compared with the cold bias of CMIP5(1.52℃).At the seasonal scale,most models exhibited a warm temperature bias in summer and a cold bias in winter.The CMIP6 MME displayed a higher reproducibility of the precipitation amplitude over dry regions compared with CMIP5 and a lower ability over wet regions.展开更多
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
China has achieved a political consensus around the need to transform the path of economic growth toward one that lowers carbon intensity and ultimately leads to reductions in carbon emissions, but there remain differ...China has achieved a political consensus around the need to transform the path of economic growth toward one that lowers carbon intensity and ultimately leads to reductions in carbon emissions, but there remain different views on pathways that could achieve such a transformation. The essential question is whether radical or incremental reforms are required in the coming decades. This study explores relevant pathways in China beyond 2020, particularly modeling the major target choices of carbon emission peaking in China around 2030 as China-US Joint Announcement by an integrated assessment model for climate change IAMC based on carbon factor theory. Here scenarios DGS-2020, LGS2025, LBS-2030 and DBS-2040 derived from the historical pathways of developed countries are developed to access the comprehensive impacts on the economy, energy and climate security for the greener development in China. The findings suggest that the period of 2025--2030 is the window of opportunity to achieve a peak in carbon emissions at a level below 12 Gt CO2 and 8.5 t per capita by reasonable trade-offs from economy growth, annually -0.2% in average and cumulatively -3% deviation to BAU in 2030. The oil and natural gas import dependence will exceed 70% and 45% respectively while the non-fossil energy and electricity share will rise to above 20% and 45%. Meantime, the electrification level in end use sectors will increase substantially and the electricity energy ratio approaching 50%, the labor and capital productivity should be double in improvements and the carbon intensity drop by 65% by 2030 compared to the 2005 level, and the cumulative emission reductions are estimated to be more than 20 Gt CO2 in 2015-2030.展开更多
Under a warming climate,degrading permafrost profoundly and extensively affects arctic and alpine ecology.However,most existing relevant studies are more focused on the hydrothermal impacts of vegetation on the underl...Under a warming climate,degrading permafrost profoundly and extensively affects arctic and alpine ecology.However,most existing relevant studies are more focused on the hydrothermal impacts of vegetation on the underlying permafrost,or symbiosis between vegetation and permafrost,only very few on ecological impacts of permafrost degradation.Additionally,there are much more pertinent investigations in arctic and boreal regions than those in alpine and high-plateau regions at mid-and low latitudes.This study emphasizes on the impact mechanisms of permafrost degradation on vegetation both at high and mid-to low latitudes,addressing vegetation succession trajectories and associated changes in soil hydrology and soil nutrient above degrading permafrost.Permafrost degradation influences vegetation by altering soil hydrology,soil biogeochemical processes and microbial communities,which further improve soil nutrient availability.Furthermore,under a warming climate,vegetation may take two successional trajectories,towards a wetter or drier ecosystem within a certain time period,but to a drier ecosystem in the end upon the thaw of permafrost in case of permeable soils and good drainage.Thus,with rapidly developing remote-sensing and other space-and ground-based and air-borne observational networks and numerical predictive models,the impacting mechanisms of permafrost degradation on vegetation should be timely and better monitored,evaluated and modeled at desired spatiotemporal scales and resolutions by terrestrial or integrated ecosystem models.展开更多
Cryosphere science research and development(R&D) has been strongly committed to public service, integrating natural sciences with socioeconomic impacts. Owing to the current shift from purely natural cryosphere sc...Cryosphere science research and development(R&D) has been strongly committed to public service, integrating natural sciences with socioeconomic impacts. Owing to the current shift from purely natural cryosphere scientific research to linking cryosphere science with socioeconomic and cultural science, cross-disciplinary research in this field is emerging, which advocates future cryosphere science research in this field. Utilizing the cryosphere service function(CSF), this study establishes CSF and its value evaluation system. Cryosphere service valuation can benefit the decisionmakers' and public's awareness of environmental protection. Implementing sustainable CSF utilization strategies and macroeconomic policymaking for global environmental protection will have profound and practical significance as well as avoid environmental degradation while pursuing short-term economic profits and achieving rapid economic development.展开更多
Recently,a hot topic about warmer and wetter climate change in the arid region of Northwest China,especially in Xinjiang,has attracted much attention by general public and scientific community.This study revisits this...Recently,a hot topic about warmer and wetter climate change in the arid region of Northwest China,especially in Xinjiang,has attracted much attention by general public and scientific community.This study revisits this topic especially for Xinjiang in the Eurasian continental context from multiple perspectives based on most updated CRU high-resolution grid data and China's homogenized station data in 1961–2019.We conclude that such‘warming-wetting’trend is not a regional phenomenon for Xinjiang but has much larger spatial scale.Regions having experienced both temperature and precipitation increases reflecting‘warming-wetting’trend account for more than half of the Eurasian continent since 1961.Nevertheless,the‘warming-wetting’trend in Xinjiang suggests some unique regional features in response to the global warming.Although drought seems to have relieved to some extent,especially in the mountainous regions in western Xinjiang,the nature of arid and semi-arid climate regime has not changed.Noticeably,the interannual variability of precipitation has enlarged and the increase in extreme precipitation events has a major contribution.These findings suggest that‘warming-wetting’trend in Xinjiang is asymmetric regarding warming and wetting in seasons and intensifying interannual variability and increasing contribution of extreme precipitation to the total.Thus,the current‘warming-wetting’trend in Xinjiang possibly brings us some beneficial impacts for the ecosystem but also increases challenges for water resources utilization and risk management.展开更多
By using the observation data from 89 weather stations in Xinjiang during 1961-2010, this paper analyzed the basic climatic elements including temperature, precipitation, wind speed, sunshine duration, water vapor pre...By using the observation data from 89 weather stations in Xinjiang during 1961-2010, this paper analyzed the basic climatic elements including temperature, precipitation, wind speed, sunshine duration, water vapor pressure, and dust storm in the entire Xinjiang and the subareas: North Xinjiang, Tianshan Mountains, and South Xinjiang. The results indicate that from 1961 to 2010 the annual and seasonal mean temperatures in the entire Xinjiang show an increasing trend with the increasing rate rising from south to north. The increasing rate of annual mean minimum temperature is over twice more than that of the annual mean maximum temperature, contributing much to the increase in the annual averages. The magnitude of the decrease rate of low-temperature days is larger than the increase rate of high-temperature days. The increase of warm days and warm nights and the decrease of cold days and cold nights further reveal that the temperature increasing in Xinjiang is higher. In addition, annual and seasonal rainfalls have been increasing. South Xinjiang experiences higher increase in rainfall amounts than North Xinjiang and Tianshan Mountains. Annual rainy days, longest consecutive rainy days, the daily maximum precipitation and extreme precipitation events, annual torrential rain days and amount, annual blizzard days and amount, all show an increasing trend, corresponding to the increasing in annual mean water vapor pressure. This result shows that the humidity has increased with temperature increasing in the past 50 years. The decrease in annual mean wind speed and gale days lessen the impact of dust storm, sandstorm, and floating dust events. The increase in annual rainy days is the cause of the decrease in annual sunshine duration, while the increase in spring sunshine duration corresponds with the decrease in dust weather. Therefore, the increase in precipitation indicators, the decrease in gales and dust weather, and the increasing in sunshine duration in spring will be beneficial to crops growth.展开更多
A quantitative model was applied to analyze the energy demand and CO2 emissions in China following the Energy Production and Consumption Revolution Strategy(2016e2030)and long-term economic and social development targ...A quantitative model was applied to analyze the energy demand and CO2 emissions in China following the Energy Production and Consumption Revolution Strategy(2016e2030)and long-term economic and social development target China Dream.Results showed that 1)toward the 2050 China Dream target,total final energy consumption is expected to peak at 3.9 Gtce in 2030 and remain stable until 2050,whereas total primary energy consumption is expected to reach an upper platform by 2040 and around 5.8 Gtce by 2050;2)the proportion of non-fossil fuels is expected to reach approximately 50%and that of natural gas to reach more than 16%by 2050;3)CO2 emissions from energy use are expected to peak at 9.6 Gt by no later than 2030 and then gradually decline to 6.7 Gt by 2050.展开更多
Northwest China is one of the most arid regions in the world and has experienced intriguing climate warming and humidification.Nonetheless,future climate conditions in Northwest China still remain uncertain.In this st...Northwest China is one of the most arid regions in the world and has experienced intriguing climate warming and humidification.Nonetheless,future climate conditions in Northwest China still remain uncertain.In this study,we applied an ensemble of the 12 latest model simulations of the Coupled Model Intercomparison Project Phase 6(CMIP6)to assess future drought conditions until 2099 in Northwest China,as inferred from the Palmer Drought Severity Index(PDSI).Future drought conditions were projected under three climate change scenarios through the combination of shared socioeconomic pathways(SSPs)and representative concentration pathways(RCPs),namely,SSP126(SSP1+RCP2.6,a green development pathway),SSP245(SSP2+RCP4.5,an intermediate development pathway),and SSP585(SSP5+RCP8.5,a high development pathway).For 2015-2099,drought severity showed no trend under SSP126,in contrast,for the SSP245 and SSP585 scenarios,a rapid increase during 2015-2099 was observed,especially under SSP585.We also found that the drought frequency in Northwest China under SSP585 was generally lower than that under SSP126 and SSP245,although the drought duration under SSP585 tended to be longer.These findings suggest the green development pathway in drought mitigation and adaptation strategies in Northwest China,an arid and agricultural region along the Silk Road.展开更多
This paper summarizes recent studies on the effects of urbanization on climate in China. The effects of urbanization on local climate trends have been re-estimated based on homogenized observations and using improved ...This paper summarizes recent studies on the effects of urbanization on climate in China. The effects of urbanization on local climate trends have been re-estimated based on homogenized observations and using improved methods. In this respect, the effect of urbanization on the observed warming trend of local surface air temperatures during the last few decades is determined as being about 20% at urban stations such as the Beijing Observatory. The large-scale weakening trend of wind speed is also about 20% more prominent at the city center than its surroundings. The effect of urbanization on precipitation is not profound, but results of high-resolution regional climate modeling suggest that this effect may depend on the urban extent. Although the urban heat island(UHI) should favor local atmospheric convection and hence precipitation, the increasingly extending urban land-use may reduce precipitation over the urban cluster in North China. It is found that urbanization can play a more notable role in extreme events than usual weather. High-resolution simulations show a positive feedback between the UHI and the super-heat wave in Shanghai during Julye August 2013. Relevant studies dealing with urban climate adaptation are discussed in relation to recent ?ndings.展开更多
Pursuant to the Paris Agreement,China committed itself to peak its carbon emissions by around 2030 and to increase the non-fossil share ofprimary energy to 20%at the same time.The government has supported the internat...Pursuant to the Paris Agreement,China committed itself to peak its carbon emissions by around 2030 and to increase the non-fossil share ofprimary energy to 20%at the same time.The government has supported the international agreement by setting and strengthening the domesticpolicy targets for an earlier peak and faster reduction,aiming to contain the average global temperature increase to well below 2℃.We developa Kaya Inequality method to assess the time of peak and pace of reduction of China's energy-related CO2emissions based on the national energypolicy targets for 2030.We find that,despite the minor fluctuations,the current plateau essentially represents the peak emissions and should entera phase of steady decline by around 2025,given current trends in energy consumption and decarbonization.Such developments would beconsistent with the strengthened national policy target to achieve 50%of renewable power generation by 2030.However,the basic policy targetsea 20%share of non-fossil energy and 6 Gtce in total energy consumption by 2030ewould be insufficient to peak carbon emissions by around 2030.The synergy and interplay between domestic policy target setting and international climate commitments shed light on the need to elevatenational climate ambitions under the Paris Agreement and beyond.展开更多
China has pledged to peak carbon emissions before 2030 and strive to achieve carbon neutrality before 2060.However,the significant variations of provincial carbon emissions make it unclear whether they can jointly ful...China has pledged to peak carbon emissions before 2030 and strive to achieve carbon neutrality before 2060.However,the significant variations of provincial carbon emissions make it unclear whether they can jointly fulfill the national carbon peak and neutrality goal.Thus,this study predicts the emission trajectories at provincial level in China by employing the extended STIRPAT(Stochastic Impacts by Regression on Population,Affluence,and Technology)model to see the feasibility and time of reaching peak carbon emissions and carbon neutrality.We found that most provinces can achieve peak emission before 2030 but challenging to achieve carbon neutrality before 2060,even considering the ecological carbon sink.The provincial neutrality time is concentrated between 2058 and 2070;the sooner the carbon emission peaks,the earlier the carbon neutral will be realized.The aggregated carbon emissions at provincial level show that China can achieve its carbon emission peak of 9.64-10.71 Gt before 2030,but it is unlikely to achieve the carbon neutrality goal before 2060 without carbon capture,utilization,and storage(CCUS).With high CCUS development,China is expected to achieve carbon neutrality in 2054-2058,irrespective of the socio-economic scenarios.With low CCUS development,China's carbon neutrality target will be achieved only under the accelerated-improvement scenario,while it will postpone to 2061 and 2064 under the continued-improvement and the business-as-usual scenarios,respectively.展开更多
While the cryosphere may bring in adverse impacts on natural and built environment, it may also provide benefits resulting from cryosphere services. By looking into the effect of the cryosphere on human-being, the stu...While the cryosphere may bring in adverse impacts on natural and built environment, it may also provide benefits resulting from cryosphere services. By looking into the effect of the cryosphere on human-being, the study develops a unified approach in the analysis of cryospheric risks and services, with one focusing on the adverse impacts by cryospheric hazards and another emphasizing on the benefits that people can obtain from the natural capitals in the cryosphere. Meanwhile, climate change could further alter and complicate the roles of the cryosphere, not only by the changes in risks to cryospheric hazards, but also the changes in services that could potentially add more risks. The study further proposed a risk-based approach for the development of climate adaptation in the cryosphere. The approach essentially takes options to reduce exposure and vulnerability of societies to cryospheric hazards, and to better manage natural capitals and demands together with enhancing utility of the cryosphere, so as to maintain the benefit of cryosphere services in a sustainable way. The study further addresses the role of cryosphere services in strengthening sustainable development in terms of its relation with the sustainable development goals (SDGs), and provides a preliminary results on how the services contributes to SDGs. Overall, the approach developed in this study creates a new way to comprehensively assess the effect of cryosphere changes on our society and identify measures to maximize the benefit while minimizing the risk in relation to the cryosphere.展开更多
Historical simulations of annual mean surface air temperature over China with 25 CMIP5 models were assessed.The observational data from CRUT3v and CN05 were used and further compared with historical simulations of CMI...Historical simulations of annual mean surface air temperature over China with 25 CMIP5 models were assessed.The observational data from CRUT3v and CN05 were used and further compared with historical simulations of CMIP3.The results show that CMIP5 models were able to simulate the observed warming over China from 1906 to 2005(0.84 C per 100 years)with a warming rate of 0.77 C per 100 years based on the multi-model ensemble(MME).The simulations of surface air temperature in the late 20th century were much better than those in the early 20th century,when only two models could reproduce the extreme warming in the 1940s.The simulations for the spatial distribution of the 20-yearmean(1986–2005)surface air temperature over China fit relatively well with the observations.However,underestimations in surface air temperature climatology were still found almost all over China,and the largest cold bias and simulation uncertainty were found in western China.On sub-regional scale,northern China experienced stronger warming than southern China during 1961–1999,for which the CMIP5 MME provided better simulations.With CMIP5 the diference of warming trends in northern and southern China was underestimated.In general,the CMIP5 simulations are obviously improved in comparison with the CMIP3 simulations in terms of the variation in regional mean surface air temperature,the spatial distribution of surface air temperature climatology and the linear trends in surface air temperature all over China.展开更多
The concept of carbon neutrality is much emphasized in IPCC Spatial Report on Global Warming of 1.5C in order to achieve the long-termtemperature goals as reflected in Paris Agreement.To keep these goals within reach,...The concept of carbon neutrality is much emphasized in IPCC Spatial Report on Global Warming of 1.5C in order to achieve the long-termtemperature goals as reflected in Paris Agreement.To keep these goals within reach,peaking the global carbon emissions as soon as possible andachieving carbon neutrality are urgently needed.However,global CO_(2)emissions continued to grow up to a record high of 43.1 Gt CO_(2)during2019,with fossil CO_(2)emissions of 36.5 Gt CO_(2)and land-use change emissions of 6.6 Gt CO_(2).In such case,the global carbon emissions mustdrop 32 Gt CO_(2)(7.6%per year)from 2020 to 2030 for the 1.5C warming limit,which is even larger than the COVID-induced reduction(6.4%)in global CO_(2)emissions during 2020.Recently,China has announced scaling up its national commitments,aiming to peak its CO_(2)emissionsbefore 2030 and achieve carbon neutrality before 2060.Achieving these goals requires rapid and far-reaching transitions in the whole society.Onthe one hand,deeper emissions reduction in all sectors includes decarbonization of energy,electrification,increasing share of renewables,energyefficiency,sustainable land management,decarbonization of transport,reducing food loss and waste,as well as behavior and lifestyles changes.On the other hand,possible actions by removing CO_(2)from the atmosphere involves enlarging land and ocean net carbon sink,CO_(2)removaltechnologies(such as Bioenergy with carbon capture and storage),and CO_(2)capture,utilization and storage technologies,but should be cautionfor their scales and tradeoffs.展开更多
In this study, the daily observational precipitation data and NCEP reanalysis data during 1951e2014, Euler and Lagrangian method were used to investigate the moisture sources of summer extreme precipitation events in ...In this study, the daily observational precipitation data and NCEP reanalysis data during 1951e2014, Euler and Lagrangian method were used to investigate the moisture sources of summer extreme precipitation events in North Xinjiang. The results show that water vapor at low and upper levels of most summer heavy rain (more than 50 mm d1 and less than 100 mm d1) in North Xinjiang are mainly transported by westerly circulation from the North Atlantic Ocean and the Eurasian continent. However, rainstorms of more than 100 mm d1, which are rarely observed, are dominated by vertically integrated moisture from the North Atlantic, Arctic Oceans, and the Eurasian continent, in addition to lowlevel moisture from the Indian Ocean. Among these sources, the anomalous low-level moisture from the Indian Ocean, which is closely associated with stronger meridional circulation, is considered to be more important with respect to rainstorms. On the days prior to rainstorm days, stronger meridional circulation leads to an anomalous pressure gradient force, which can transport low-level moisture from the Indian Ocean along the eastern periphery of the Tibetan Plateau to North Xinjiang. Furthermore, moisture from the North Atlantic, Arctic Oceans, the Eurasian continent, and the Indian Ocean converge together to influence rainstorm development in this region.展开更多
The climate system models from Beijing Climate Center, BCC_CSM1.1 and BCC_CSM1.1-M, are used to carry out most of the CMIP5 experiments. This study gives a general introduction of these two models, and provides main i...The climate system models from Beijing Climate Center, BCC_CSM1.1 and BCC_CSM1.1-M, are used to carry out most of the CMIP5 experiments. This study gives a general introduction of these two models, and provides main information on the experiments including the experiment purpose, design, and the external forcings. The transient climate responses to the CO2 concentration increase at 1% per year are presented in the simulation of the two models. The BCC_CSM1.1-M result is closer to the CMIP5 multiple models ensemble. The two models perform well in simulating the historical evolution of the surface air temperature, globally and averaged for China. Both models overestimate the global warming and underestimate the warming over China in the 20th century. With higher horizontal resolution, the BCC_CSM1.1-M has a better capability in reproducing the annual evolution of surface air temperature over China.展开更多
This study investigated the projected changes in the annual mean surface air temperature （SAT） over China under the 1.5 and 2.0 ℃ targets, by analyzing the outputs from 22 models of the Coupled Model Intercompariso...This study investigated the projected changes in the annual mean surface air temperature （SAT） over China under the 1.5 and 2.0 ℃ targets, by analyzing the outputs from 22 models of the Coupled Model Intercomparison Project Phase 5. Under the 1.5 ℃ target, the scope of changes in the average SAT over China is quite narrow and has the largest probability to increase by 1.7-2.0 ℃ under the various RCP pathways, although the time of occurrence of the 1.5 ℃ target has a large spread of 40-60 years. Similarly, the models consistently show that the average SAT over China would most likely increase by 2.4-2.7 ℃ under the 2.0 ℃ target. Furthermore, the warming shows a clear spatial distinction over China： being stronger in the northwest part and weaker in the southeast part. Under all RCP pathways, the SAT over the northwest part would increase by 1.9-2.1 ℃ for the 1.5℃ target, which is much stronger than the SAT increase over the southeast part （1.3-1.5 ℃）. A similar spatial pattern appears for the 2.0 ℃ target.展开更多
China has set the goal for its CO2 emissions to peak around 2030, which is not only a strategic decision coordinating domestic sustainable development and global climate change mitigation but also an overarching targe...China has set the goal for its CO2 emissions to peak around 2030, which is not only a strategic decision coordinating domestic sustainable development and global climate change mitigation but also an overarching target and a key point of action for China＇s resource conservation, environmental protection, shift in economic development patterns, and CO2 emission reduction to avoid climate change. The development stage where China maps out the CO2 emission peak target is earlier than that of the developed countries. It is a necessity that the non-fossil energy supplies be able to meet all the increased energy demand for achieving CO2 emission peaking. Given that China＇s potential GDP annual increasing rate will be more than 4%, and China＇s total energy demand will continue to increase by approximately 1.0%--1.5% annually around 2030, new and renewable energies will need to increase by 6%-8% annually to meet the desired CO2 emission peak. The share of new and renewable energies in China＇s total primary energy supply will be approximately 20% by 2030. At that time, the energy consumption elasticity will decrease to around 0.3, and the annual decrease in the rate of CO2 intensity will also be higher than 4% to ensure the sustained growth of GDE To achieve the CO2 emission peaking target and substantially promote the low-carbon deve!opment transformation, China needs to actively promote an energy production and consumption revolution, the innovation of advanced energy technologies, the reform of the energy regulatory system and pricing mechanism, and especially the construction of a national carbon emission cap and trade system.展开更多
The present study focused on statistical analysis of interannual, interdecadal variations of climate variables and extreme climate events during the period of 1961-2010 using observational data from 376 meteorological...The present study focused on statistical analysis of interannual, interdecadal variations of climate variables and extreme climate events during the period of 1961-2010 using observational data from 376 meteorological stations uniformly distributed across Southwest China, which includes Yunnan, Guizhou, Chongqing, Sichuan and Tibet. It was found that temperatures in most of the region were warming and this was especially evident for areas at high elevation. The warming was mostly attributable to the increase in annual mean minimum temperature. The characteristics of high temperature/heat waves are increase in frequency, prolonged duration, and weakened intensity. Annual precipitation showed a weak decreasing trend and drier in the east and more rainfall in the west. The precipitation amount in flood season was declining markedly in the whole region; rainfall from extreme heavy precipitation did not change much, and the portion of annual precipitation contributed by extreme heavy precipitation had an increasing trend; annual non-rainy days and the longest consecutive non-rainy days were both increasing; the extreme drought had a decreasing trend since the 1990s; the autumn-rain days displayed a downward fluctuation with apparent periodicity and intermittency. The number of southwestern vortices was decreasing whereas the number of moving vortices increased.展开更多
基金sponsored by the National Key Research and Development Program of China(2016YFA0602403)the National Natural Science Foundation of China(41621061)supported by the International Center for Collaborative Research on Disaster Risk Reduction(ICCR-DRR).
文摘A model-by-model analysis for historical simulations was necessary for identifying reasonably performing models in the updated Coupled Model Intercomparison Project(CMIP6)over the Tibetan Plateau.To determine whether the capacity of the CMIP6 models in simulating temperature and precipitation over the Plateau has been enhanced,we compared the outputs of 23 CMIP6 models with an observational dataset(CN05.1)for the period 1961–2014.The results suggest the systematic model biases(cold bias and wet bias)in the Tibetan Plateau still exist in CMIP6.Most models in CMIP6 realistically simulated the surface temperature and spatial distribution of precipitation,with a pattern correlation exceeding 0.75.The bias in the mean surface temperature of the multi-model ensemble(MME)simulation was 1.08℃ lower than the observational data,which had been decreased compared with the cold bias of CMIP5(1.52℃).At the seasonal scale,most models exhibited a warm temperature bias in summer and a cold bias in winter.The CMIP6 MME displayed a higher reproducibility of the precipitation amplitude over dry regions compared with CMIP5 and a lower ability over wet regions.
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.
基金supported by National Science and Technology Program"The Key Supporting Research of The International Negotiations on Climate Change and the Domestic Emission Reduction"(2012BAC20B04)
文摘China has achieved a political consensus around the need to transform the path of economic growth toward one that lowers carbon intensity and ultimately leads to reductions in carbon emissions, but there remain different views on pathways that could achieve such a transformation. The essential question is whether radical or incremental reforms are required in the coming decades. This study explores relevant pathways in China beyond 2020, particularly modeling the major target choices of carbon emission peaking in China around 2030 as China-US Joint Announcement by an integrated assessment model for climate change IAMC based on carbon factor theory. Here scenarios DGS-2020, LGS2025, LBS-2030 and DBS-2040 derived from the historical pathways of developed countries are developed to access the comprehensive impacts on the economy, energy and climate security for the greener development in China. The findings suggest that the period of 2025--2030 is the window of opportunity to achieve a peak in carbon emissions at a level below 12 Gt CO2 and 8.5 t per capita by reasonable trade-offs from economy growth, annually -0.2% in average and cumulatively -3% deviation to BAU in 2030. The oil and natural gas import dependence will exceed 70% and 45% respectively while the non-fossil energy and electricity share will rise to above 20% and 45%. Meantime, the electrification level in end use sectors will increase substantially and the electricity energy ratio approaching 50%, the labor and capital productivity should be double in improvements and the carbon intensity drop by 65% by 2030 compared to the 2005 level, and the cumulative emission reductions are estimated to be more than 20 Gt CO2 in 2015-2030.
基金supported by the National Natural Science Foundation of China(NSFC)Program on Study on impacts of forest fires on the permafrost environment in the Da Xing’anling Mountains,Northeast China(41871052)State Key Laboratory of Frozen Soils Engineering(SKLFSE)program Fire-induced changes in the permafrost environment in Alaska:Observations,modeling and assessment(SKLFSE201811)。
文摘Under a warming climate,degrading permafrost profoundly and extensively affects arctic and alpine ecology.However,most existing relevant studies are more focused on the hydrothermal impacts of vegetation on the underlying permafrost,or symbiosis between vegetation and permafrost,only very few on ecological impacts of permafrost degradation.Additionally,there are much more pertinent investigations in arctic and boreal regions than those in alpine and high-plateau regions at mid-and low latitudes.This study emphasizes on the impact mechanisms of permafrost degradation on vegetation both at high and mid-to low latitudes,addressing vegetation succession trajectories and associated changes in soil hydrology and soil nutrient above degrading permafrost.Permafrost degradation influences vegetation by altering soil hydrology,soil biogeochemical processes and microbial communities,which further improve soil nutrient availability.Furthermore,under a warming climate,vegetation may take two successional trajectories,towards a wetter or drier ecosystem within a certain time period,but to a drier ecosystem in the end upon the thaw of permafrost in case of permeable soils and good drainage.Thus,with rapidly developing remote-sensing and other space-and ground-based and air-borne observational networks and numerical predictive models,the impacting mechanisms of permafrost degradation on vegetation should be timely and better monitored,evaluated and modeled at desired spatiotemporal scales and resolutions by terrestrial or integrated ecosystem models.
基金funded by National Basic Research Program of China (2013CBA01804, 2013CBA01808)Technology Services Network Program (STS-HHS Program) of Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciencesthe independent subject from Stake Key Laboratory of Cryospheric Sciences, Chinese Academy of Sciences
文摘Cryosphere science research and development(R&D) has been strongly committed to public service, integrating natural sciences with socioeconomic impacts. Owing to the current shift from purely natural cryosphere scientific research to linking cryosphere science with socioeconomic and cultural science, cross-disciplinary research in this field is emerging, which advocates future cryosphere science research in this field. Utilizing the cryosphere service function(CSF), this study establishes CSF and its value evaluation system. Cryosphere service valuation can benefit the decisionmakers' and public's awareness of environmental protection. Implementing sustainable CSF utilization strategies and macroeconomic policymaking for global environmental protection will have profound and practical significance as well as avoid environmental degradation while pursuing short-term economic profits and achieving rapid economic development.
基金supported by the National Key Research and Development Program of China(2018YFC1507700).
文摘Recently,a hot topic about warmer and wetter climate change in the arid region of Northwest China,especially in Xinjiang,has attracted much attention by general public and scientific community.This study revisits this topic especially for Xinjiang in the Eurasian continental context from multiple perspectives based on most updated CRU high-resolution grid data and China's homogenized station data in 1961–2019.We conclude that such‘warming-wetting’trend is not a regional phenomenon for Xinjiang but has much larger spatial scale.Regions having experienced both temperature and precipitation increases reflecting‘warming-wetting’trend account for more than half of the Eurasian continent since 1961.Nevertheless,the‘warming-wetting’trend in Xinjiang suggests some unique regional features in response to the global warming.Although drought seems to have relieved to some extent,especially in the mountainous regions in western Xinjiang,the nature of arid and semi-arid climate regime has not changed.Noticeably,the interannual variability of precipitation has enlarged and the increase in extreme precipitation events has a major contribution.These findings suggest that‘warming-wetting’trend in Xinjiang is asymmetric regarding warming and wetting in seasons and intensifying interannual variability and increasing contribution of extreme precipitation to the total.Thus,the current‘warming-wetting’trend in Xinjiang possibly brings us some beneficial impacts for the ecosystem but also increases challenges for water resources utilization and risk management.
基金supported by China Meteorological Administration (CMA) Specific Research on ClimateChange (No. CCSF-10-06)the National Key Scientific Research Program of Global Change (No. 2010CB951001)
文摘By using the observation data from 89 weather stations in Xinjiang during 1961-2010, this paper analyzed the basic climatic elements including temperature, precipitation, wind speed, sunshine duration, water vapor pressure, and dust storm in the entire Xinjiang and the subareas: North Xinjiang, Tianshan Mountains, and South Xinjiang. The results indicate that from 1961 to 2010 the annual and seasonal mean temperatures in the entire Xinjiang show an increasing trend with the increasing rate rising from south to north. The increasing rate of annual mean minimum temperature is over twice more than that of the annual mean maximum temperature, contributing much to the increase in the annual averages. The magnitude of the decrease rate of low-temperature days is larger than the increase rate of high-temperature days. The increase of warm days and warm nights and the decrease of cold days and cold nights further reveal that the temperature increasing in Xinjiang is higher. In addition, annual and seasonal rainfalls have been increasing. South Xinjiang experiences higher increase in rainfall amounts than North Xinjiang and Tianshan Mountains. Annual rainy days, longest consecutive rainy days, the daily maximum precipitation and extreme precipitation events, annual torrential rain days and amount, annual blizzard days and amount, all show an increasing trend, corresponding to the increasing in annual mean water vapor pressure. This result shows that the humidity has increased with temperature increasing in the past 50 years. The decrease in annual mean wind speed and gale days lessen the impact of dust storm, sandstorm, and floating dust events. The increase in annual rainy days is the cause of the decrease in annual sunshine duration, while the increase in spring sunshine duration corresponds with the decrease in dust weather. Therefore, the increase in precipitation indicators, the decrease in gales and dust weather, and the increasing in sunshine duration in spring will be beneficial to crops growth.
基金We thank National Key R&D Program of China(2016YFA0602601),National Natural Science Foundation of China(71573062),China Energy Modeling Forum(CEMF),for support of the study.
文摘A quantitative model was applied to analyze the energy demand and CO2 emissions in China following the Energy Production and Consumption Revolution Strategy(2016e2030)and long-term economic and social development target China Dream.Results showed that 1)toward the 2050 China Dream target,total final energy consumption is expected to peak at 3.9 Gtce in 2030 and remain stable until 2050,whereas total primary energy consumption is expected to reach an upper platform by 2040 and around 5.8 Gtce by 2050;2)the proportion of non-fossil fuels is expected to reach approximately 50%and that of natural gas to reach more than 16%by 2050;3)CO2 emissions from energy use are expected to peak at 9.6 Gt by no later than 2030 and then gradually decline to 6.7 Gt by 2050.
基金financially supported by the National Key Research and Development Program of China(2017YFA0603804)the Key Project of National Social and Scientific Fund Program(16ZDA047)+2 种基金the European Union's Framework Programme for Research and Innovation Horizon 2020(2014—2020)under the Marie Sklodowska-Curie Agreement(795179)the Alexander von Humboldt Foundation of GermanyPostgraduate Research&Practice Innovation Program of Jiangsu Province(SJKY19_0961).
文摘Northwest China is one of the most arid regions in the world and has experienced intriguing climate warming and humidification.Nonetheless,future climate conditions in Northwest China still remain uncertain.In this study,we applied an ensemble of the 12 latest model simulations of the Coupled Model Intercomparison Project Phase 6(CMIP6)to assess future drought conditions until 2099 in Northwest China,as inferred from the Palmer Drought Severity Index(PDSI).Future drought conditions were projected under three climate change scenarios through the combination of shared socioeconomic pathways(SSPs)and representative concentration pathways(RCPs),namely,SSP126(SSP1+RCP2.6,a green development pathway),SSP245(SSP2+RCP4.5,an intermediate development pathway),and SSP585(SSP5+RCP8.5,a high development pathway).For 2015-2099,drought severity showed no trend under SSP126,in contrast,for the SSP245 and SSP585 scenarios,a rapid increase during 2015-2099 was observed,especially under SSP585.We also found that the drought frequency in Northwest China under SSP585 was generally lower than that under SSP126 and SSP245,although the drought duration under SSP585 tended to be longer.These findings suggest the green development pathway in drought mitigation and adaptation strategies in Northwest China,an arid and agricultural region along the Silk Road.
基金supported by the Chinese Academy of Sciences (XDA05090000)the National Natural Science Foundation (41475078)
文摘This paper summarizes recent studies on the effects of urbanization on climate in China. The effects of urbanization on local climate trends have been re-estimated based on homogenized observations and using improved methods. In this respect, the effect of urbanization on the observed warming trend of local surface air temperatures during the last few decades is determined as being about 20% at urban stations such as the Beijing Observatory. The large-scale weakening trend of wind speed is also about 20% more prominent at the city center than its surroundings. The effect of urbanization on precipitation is not profound, but results of high-resolution regional climate modeling suggest that this effect may depend on the urban extent. Although the urban heat island(UHI) should favor local atmospheric convection and hence precipitation, the increasingly extending urban land-use may reduce precipitation over the urban cluster in North China. It is found that urbanization can play a more notable role in extreme events than usual weather. High-resolution simulations show a positive feedback between the UHI and the super-heat wave in Shanghai during Julye August 2013. Relevant studies dealing with urban climate adaptation are discussed in relation to recent ?ndings.
基金This project is supported by National Natural ScienceFoundation of China Innovative Research Groups Program‘Research on Chinese Public Policy Theory and GovernanceMechanism’(71721002)The Clean DevelopmentMechanism Funding Program‘Study on the Possibility ofChina's Early Emission Peak in the Context of Global Low-Carbon Development’(2013081)。
文摘Pursuant to the Paris Agreement,China committed itself to peak its carbon emissions by around 2030 and to increase the non-fossil share ofprimary energy to 20%at the same time.The government has supported the international agreement by setting and strengthening the domesticpolicy targets for an earlier peak and faster reduction,aiming to contain the average global temperature increase to well below 2℃.We developa Kaya Inequality method to assess the time of peak and pace of reduction of China's energy-related CO2emissions based on the national energypolicy targets for 2030.We find that,despite the minor fluctuations,the current plateau essentially represents the peak emissions and should entera phase of steady decline by around 2025,given current trends in energy consumption and decarbonization.Such developments would beconsistent with the strengthened national policy target to achieve 50%of renewable power generation by 2030.However,the basic policy targetsea 20%share of non-fossil energy and 6 Gtce in total energy consumption by 2030ewould be insufficient to peak carbon emissions by around 2030.The synergy and interplay between domestic policy target setting and international climate commitments shed light on the need to elevatenational climate ambitions under the Paris Agreement and beyond.
基金supported by the National Key Research and Development Program of China(2017YFA0605303)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA23100401)+3 种基金the National Natural Science Foundation of China(41877454)China Postdoctoral Science Foundation(2019M650824)the Youth Innovation Promotion Association of CAS(2019053)the Young Talents in IGSNRR,CAS(2017RC201).
文摘China has pledged to peak carbon emissions before 2030 and strive to achieve carbon neutrality before 2060.However,the significant variations of provincial carbon emissions make it unclear whether they can jointly fulfill the national carbon peak and neutrality goal.Thus,this study predicts the emission trajectories at provincial level in China by employing the extended STIRPAT(Stochastic Impacts by Regression on Population,Affluence,and Technology)model to see the feasibility and time of reaching peak carbon emissions and carbon neutrality.We found that most provinces can achieve peak emission before 2030 but challenging to achieve carbon neutrality before 2060,even considering the ecological carbon sink.The provincial neutrality time is concentrated between 2058 and 2070;the sooner the carbon emission peaks,the earlier the carbon neutral will be realized.The aggregated carbon emissions at provincial level show that China can achieve its carbon emission peak of 9.64-10.71 Gt before 2030,but it is unlikely to achieve the carbon neutrality goal before 2060 without carbon capture,utilization,and storage(CCUS).With high CCUS development,China is expected to achieve carbon neutrality in 2054-2058,irrespective of the socio-economic scenarios.With low CCUS development,China's carbon neutrality target will be achieved only under the accelerated-improvement scenario,while it will postpone to 2061 and 2064 under the continued-improvement and the business-as-usual scenarios,respectively.
基金Natural Science Foundation of China(41690141)Project of Chinese Academy of Sciences(XDA20100305).
文摘While the cryosphere may bring in adverse impacts on natural and built environment, it may also provide benefits resulting from cryosphere services. By looking into the effect of the cryosphere on human-being, the study develops a unified approach in the analysis of cryospheric risks and services, with one focusing on the adverse impacts by cryospheric hazards and another emphasizing on the benefits that people can obtain from the natural capitals in the cryosphere. Meanwhile, climate change could further alter and complicate the roles of the cryosphere, not only by the changes in risks to cryospheric hazards, but also the changes in services that could potentially add more risks. The study further proposed a risk-based approach for the development of climate adaptation in the cryosphere. The approach essentially takes options to reduce exposure and vulnerability of societies to cryospheric hazards, and to better manage natural capitals and demands together with enhancing utility of the cryosphere, so as to maintain the benefit of cryosphere services in a sustainable way. The study further addresses the role of cryosphere services in strengthening sustainable development in terms of its relation with the sustainable development goals (SDGs), and provides a preliminary results on how the services contributes to SDGs. Overall, the approach developed in this study creates a new way to comprehensively assess the effect of cryosphere changes on our society and identify measures to maximize the benefit while minimizing the risk in relation to the cryosphere.
文摘Historical simulations of annual mean surface air temperature over China with 25 CMIP5 models were assessed.The observational data from CRUT3v and CN05 were used and further compared with historical simulations of CMIP3.The results show that CMIP5 models were able to simulate the observed warming over China from 1906 to 2005(0.84 C per 100 years)with a warming rate of 0.77 C per 100 years based on the multi-model ensemble(MME).The simulations of surface air temperature in the late 20th century were much better than those in the early 20th century,when only two models could reproduce the extreme warming in the 1940s.The simulations for the spatial distribution of the 20-yearmean(1986–2005)surface air temperature over China fit relatively well with the observations.However,underestimations in surface air temperature climatology were still found almost all over China,and the largest cold bias and simulation uncertainty were found in western China.On sub-regional scale,northern China experienced stronger warming than southern China during 1961–1999,for which the CMIP5 MME provided better simulations.With CMIP5 the diference of warming trends in northern and southern China was underestimated.In general,the CMIP5 simulations are obviously improved in comparison with the CMIP3 simulations in terms of the variation in regional mean surface air temperature,the spatial distribution of surface air temperature climatology and the linear trends in surface air temperature all over China.
基金the Basic Research to Operation Funds of the Chinese Academy of Meteorological Sciences(2020Y004)National Key Research and Development Program of China(2018YFC1507700).
文摘The concept of carbon neutrality is much emphasized in IPCC Spatial Report on Global Warming of 1.5C in order to achieve the long-termtemperature goals as reflected in Paris Agreement.To keep these goals within reach,peaking the global carbon emissions as soon as possible andachieving carbon neutrality are urgently needed.However,global CO_(2)emissions continued to grow up to a record high of 43.1 Gt CO_(2)during2019,with fossil CO_(2)emissions of 36.5 Gt CO_(2)and land-use change emissions of 6.6 Gt CO_(2).In such case,the global carbon emissions mustdrop 32 Gt CO_(2)(7.6%per year)from 2020 to 2030 for the 1.5C warming limit,which is even larger than the COVID-induced reduction(6.4%)in global CO_(2)emissions during 2020.Recently,China has announced scaling up its national commitments,aiming to peak its CO_(2)emissionsbefore 2030 and achieve carbon neutrality before 2060.Achieving these goals requires rapid and far-reaching transitions in the whole society.Onthe one hand,deeper emissions reduction in all sectors includes decarbonization of energy,electrification,increasing share of renewables,energyefficiency,sustainable land management,decarbonization of transport,reducing food loss and waste,as well as behavior and lifestyles changes.On the other hand,possible actions by removing CO_(2)from the atmosphere involves enlarging land and ocean net carbon sink,CO_(2)removaltechnologies(such as Bioenergy with carbon capture and storage),and CO_(2)capture,utilization and storage technologies,but should be cautionfor their scales and tradeoffs.
文摘In this study, the daily observational precipitation data and NCEP reanalysis data during 1951e2014, Euler and Lagrangian method were used to investigate the moisture sources of summer extreme precipitation events in North Xinjiang. The results show that water vapor at low and upper levels of most summer heavy rain (more than 50 mm d1 and less than 100 mm d1) in North Xinjiang are mainly transported by westerly circulation from the North Atlantic Ocean and the Eurasian continent. However, rainstorms of more than 100 mm d1, which are rarely observed, are dominated by vertically integrated moisture from the North Atlantic, Arctic Oceans, and the Eurasian continent, in addition to lowlevel moisture from the Indian Ocean. Among these sources, the anomalous low-level moisture from the Indian Ocean, which is closely associated with stronger meridional circulation, is considered to be more important with respect to rainstorms. On the days prior to rainstorm days, stronger meridional circulation leads to an anomalous pressure gradient force, which can transport low-level moisture from the Indian Ocean along the eastern periphery of the Tibetan Plateau to North Xinjiang. Furthermore, moisture from the North Atlantic, Arctic Oceans, the Eurasian continent, and the Indian Ocean converge together to influence rainstorm development in this region.
基金supported by the National Basic Research Program of China (973 Program) under No. 2010CB951903the National Science Foundation of China under Grant No. 41105054, 41205043the China Meteorological Administration under Grant No.GYHY201106022, GYHY201306048, CMAYBY2012-001
文摘The climate system models from Beijing Climate Center, BCC_CSM1.1 and BCC_CSM1.1-M, are used to carry out most of the CMIP5 experiments. This study gives a general introduction of these two models, and provides main information on the experiments including the experiment purpose, design, and the external forcings. The transient climate responses to the CO2 concentration increase at 1% per year are presented in the simulation of the two models. The BCC_CSM1.1-M result is closer to the CMIP5 multiple models ensemble. The two models perform well in simulating the historical evolution of the surface air temperature, globally and averaged for China. Both models overestimate the global warming and underestimate the warming over China in the 20th century. With higher horizontal resolution, the BCC_CSM1.1-M has a better capability in reproducing the annual evolution of surface air temperature over China.
基金We thank two anonymous reviewers and Professor Gao Xuejie for their various constructive and detailed comments, which have greatly helped us to improve the presentation of this paper. This research was supported by the National Key R＆D Program of China （2017YFA0603802） and the National Natural Science Foundation of China （41675084）.
文摘This study investigated the projected changes in the annual mean surface air temperature （SAT） over China under the 1.5 and 2.0 ℃ targets, by analyzing the outputs from 22 models of the Coupled Model Intercomparison Project Phase 5. Under the 1.5 ℃ target, the scope of changes in the average SAT over China is quite narrow and has the largest probability to increase by 1.7-2.0 ℃ under the various RCP pathways, although the time of occurrence of the 1.5 ℃ target has a large spread of 40-60 years. Similarly, the models consistently show that the average SAT over China would most likely increase by 2.4-2.7 ℃ under the 2.0 ℃ target. Furthermore, the warming shows a clear spatial distinction over China： being stronger in the northwest part and weaker in the southeast part. Under all RCP pathways, the SAT over the northwest part would increase by 1.9-2.1 ℃ for the 1.5℃ target, which is much stronger than the SAT increase over the southeast part （1.3-1.5 ℃）. A similar spatial pattern appears for the 2.0 ℃ target.
基金supported by Major Program of Humanities and Social Science Base,Ministry of Education(No.10JJD630011)
文摘China has set the goal for its CO2 emissions to peak around 2030, which is not only a strategic decision coordinating domestic sustainable development and global climate change mitigation but also an overarching target and a key point of action for China＇s resource conservation, environmental protection, shift in economic development patterns, and CO2 emission reduction to avoid climate change. The development stage where China maps out the CO2 emission peak target is earlier than that of the developed countries. It is a necessity that the non-fossil energy supplies be able to meet all the increased energy demand for achieving CO2 emission peaking. Given that China＇s potential GDP annual increasing rate will be more than 4%, and China＇s total energy demand will continue to increase by approximately 1.0%--1.5% annually around 2030, new and renewable energies will need to increase by 6%-8% annually to meet the desired CO2 emission peak. The share of new and renewable energies in China＇s total primary energy supply will be approximately 20% by 2030. At that time, the energy consumption elasticity will decrease to around 0.3, and the annual decrease in the rate of CO2 intensity will also be higher than 4% to ensure the sustained growth of GDE To achieve the CO2 emission peaking target and substantially promote the low-carbon deve!opment transformation, China needs to actively promote an energy production and consumption revolution, the innovation of advanced energy technologies, the reform of the energy regulatory system and pricing mechanism, and especially the construction of a national carbon emission cap and trade system.
基金supported by the special climate change in 2010 of the China Meteorological Administration (No. ccfs-2010)the National Natural Science Foundation of China (No. 41275097)
文摘The present study focused on statistical analysis of interannual, interdecadal variations of climate variables and extreme climate events during the period of 1961-2010 using observational data from 376 meteorological stations uniformly distributed across Southwest China, which includes Yunnan, Guizhou, Chongqing, Sichuan and Tibet. It was found that temperatures in most of the region were warming and this was especially evident for areas at high elevation. The warming was mostly attributable to the increase in annual mean minimum temperature. The characteristics of high temperature/heat waves are increase in frequency, prolonged duration, and weakened intensity. Annual precipitation showed a weak decreasing trend and drier in the east and more rainfall in the west. The precipitation amount in flood season was declining markedly in the whole region; rainfall from extreme heavy precipitation did not change much, and the portion of annual precipitation contributed by extreme heavy precipitation had an increasing trend; annual non-rainy days and the longest consecutive non-rainy days were both increasing; the extreme drought had a decreasing trend since the 1990s; the autumn-rain days displayed a downward fluctuation with apparent periodicity and intermittency. The number of southwestern vortices was decreasing whereas the number of moving vortices increased.
