Assessment on Temperature Changes of China During the Past 2000 Years

The Fourth Assessment Report of IPCC(IPCC AR4)concluded that average Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than that of any other 50-year period in the last 500 years and likely the highest in at least the past 1300 years.However,after evaluating Global or Northern Hemisphere temperature change series derived from ice cores,tree rings,

Thirty Vears Road,Integrating a Megacity——Economic Changes inthe Yangtze River Delta Over the Past 30 Years

As one of the most dynamic economic zones in China, the Yangtze River Delta has further increased its economic output,becoming more open to foreign investment and international cooperation over the past 30 years.Its economic stability and coordination have been strengthened;and the process of regional integration continues to accelerate.

60 YEARS OF CHANGES IN MY HOMETOWN

'I come from the town of Zari, one of the six towns in the Luntse County of Lhoka City that line the border of the Tibet Autonomous Region, not too far away from the nationally famous town of Yulmed.'

Changes in Ten Years In Nyingchi

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Three Development Stages for the Tibetan Family and Tibet's Modernization——A Survey of Social Changes in Tibet in Last 50 Years

I Since 1990, as a person in charge of key research projects of the China Tibetology Research Center, I have had opportunities almost every year to conduct field surveys on anthropology in Tibet together with my colleagues. Our investigations focus on the family. The purpose of our surveys is to see social changes in Tibet during the 50 years after the Democratic Reform through the study of the family as a social cell.

The ostracod assemblages and their environmental significance in the Chen Co area, southern Tibet in recent 1400 years

The CC1 core, with a length of 216 cm, was drilled in the west part of the Chen Co (Lake) in southern Tibet Plateau. The210Pb and137Cs measurement indicated that it was a consecutive sedimentary sequence since ca. 1400 years. The ostracoda and their assemblages under the level of 1 cm samples’ cutting interval were finished for this core to reveal the past environmental changes in the lake area. A total of 15 species of ostracods belonging to 7 genera in the core sediments had been identified. According to the ostracod distributions, abundances and preservations in the core, seven ostracod assemblages had been distinguished. The ostracod assemblages and their ecological features, together with the sediments dating decision were used to infer the past ca. 1400 years environmental changes of the Chen Co environmental evolutions in three stages, which had responded to the Medieval Ages Warm-period (MAW), the Little Ice Age (LIA) and modern warm period. The results show that the changes of the Chen Co environment had been mainly influenced by the climatic variations. The trend of the lake level fluctuations had been accorded with that of climatic variation during the past 1400 years.

Characteristics of Temperature Change in China over the Last 2000 years and Spatial Patterns of Dryness/Wetness during Cold and Warm Periods

This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50–70-yr, 100–120-yr, and 200–250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3℃ and 0.7℃, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870–2000, at a rate of 0.56°± 0.42℃（100 yr）^（-1）; however, temperatures recorded in the 20 th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981–1100 and AD1201–70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern： dry south of 25°N, wet from 25°–30°N, and dry to the north of 30°N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20 th century warming can primarily be attributed to a mega El Nino–Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China.

Analysis of Climate Change in the Coastal Zone of Eastern China, against the Background of Global Climate Change over the Last Fifty Years: Case Study of Shandong Peninsula, China

The climate change in Shandong Peninsula, China was analyzed in this paper by the non-parametric Mann-Kendall test, Accumulated Difference Curve and Order Cluster Analysis methods, based upon the datas of annual mean, maximum and minimum temperature and annual precipitation, precipitation from June to September over the past 50 years. Results obtained showed a number of observations: 1) The annual mean temperature of Shandong Peninsula showed a significant increasing trend, with a distinct abrupt change point detected around 1990, during the past 5 decades. The warming of the Peninsula over the last 50 years was due mainly to the significant increase of annual minimum temperature. The annual maximum temperature demonstrated a mixed trend of decreasing and increasing, but was statistically insignificant, and no abrupt change was detected;2) The annual precipitation exhibited a decreasing trend during the past 5 decades, with an abrupt change detected around 1980 at most stations;but there was an earlier transition point at 1966, at a few stations. The reduction in precipitation, from June to September, was responsible mainly for the decrease of annual precipitation. Besides, the proportion of the June-September precipitation in the year declined slightly over the last 50 years;3) In comparison, the temperature evolution in Shandong Peninsula was basically consistent with most parts of China, but warmed at a faster rate over the same period;the decreasing trend of precipitation was more significant compared with the other climate zones of China. Within the Peninsula, the abrupt change of temperature and precipitation in the Southeast was earlier than that in the Northwest;the reduction of precipitation was larger in the Southeast while the increase of temperature was more significant in the Northwest. This research was of great importance to understand the climate change and its environmental effects in the coastal zone.

A bruptchanges in an 8000-year precipitationreconst ruction for Nevada,the Western USA

A scanning t-test algorithm for detecting multiple time-scale abrupt changes in the level of a time-series was used to analyze an 8000 year time series of annual precipitation which was reconstructed from tree rings for the Nevada Climate Division 3 in the western USA. The tree ring samples were gathered from eight states in the southwestern USA. Twenty-two change-points were identified by the algorithm and these were used to partition the tree-ring series into twenty-three relatively Wet/Normal/Dry episodes. These twenty-three episodes were collaborated by a coherency analysis of abrupt changes between the precipitation reconstruction series and the TIC/δ^18O records from cored sediments of Pyramid Lake in Nevada, and by comparison with published results from related studies. These episodes were also compared with studies of the global climate change and with records of climate change in China during the same periods. The results suggest that the precipitation reconstruction series is quite valuable for climate-change research on multi-centurial time-scales in the western USA, and that the scanning t-test and coherency detection algorithms may have a wide use for detecting multiple time-scale abrupt changes in a long time series. As the TIC and δ^18O record series are high resolution with unequal sampling intervals ranging between 3 and 14 years, a new algorithm was developed to deal with the unequal time intervals in the series.

Age Structure and Change Trend of Tobacco Farmers:A Case Study of Shashi Town,Liuyang City,Hunan Province

Taking the tobacco-growing area of Shashi Town,Liuyang City as the object,the number of registered,newly added and resigned tobacco farmers in each year,average age,number and proportion of tobacco farmers of different ages,number and proportion of tobacco farmers born in different eras,as well as planting scale and planting history of flue-cured tobacco in the last 10 years were analyzed statistically.The results showed that the number of tobacco farmers in Shashi Town showed a rapid decline trend from 2012 to 2018,while the average age continuously increased,and the average planting scale rose in a wave like way.From 2019 to 2021,the decline rate of the number of tobacco farmers slowed down,and the average planting scale continuously increased,while the aging of tobacco farmers accelerated.Meantime,the birth years of tobacco farmers were further concentrated in the 1960s,and they were mainly at the age of 50-59.The tobacco industry in Shashi Town of Liuyang City is facing the crisis of aging tobacco farmers and no successor of flue-cured tobacco planting,and it is predicted that the next 5-10 years will continue the change trend from 2019 to 2021.

Agriculture Development-induced Surface Albedo Changes and Climatic Implications Across Northeastern China

To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeastern China over the last 300 years,and its climatic effects were simulated by using the Weather Research and Forecasting (WRF) model.Essential natural vegetation records compiled from historical documents and regional optimal surface albedo dataset were used.The results show that the surface albedo decreased by 0.01-0.03 due to conversions from grassland to cropland in the Northeast China Plain and it increased by 0.005-0.015 due to conversions from forests to cropland in the surrounding mountains.As a consequence,in the Northeast China Plain,the surface net radiation increased by 4-8 W/m 2,2-5 W/m 2,and 1-3 W/m 2,and the climate was therefore warmed by 0.1℃-0.2℃、0.1℃-0.2℃、 0.1℃-0.3 ℃ in the spring,autumn and winter,respectively.In the surrounding mountain area,the net radiation decreased by less than 1.5 W/m 2,and the climate was therefore cooled too slight to be detected.In summer,effects of surface albedo changes on climate were closely associated with moisture dynamics,such as evapotranspiration and cloud,instead of being merely determined by surface radiation budget.The simulated summer climatic effects have large uncertainties.These findings demonstrate that surface albedo changes resulted in warming climate effects in the non-rainy seasons in Northeast China Plain through surface radiation processes while the climatic effects in summer could hardly be concluded so far.

Procreation Anxiety in Climate Crisis:Comparative Analysis of The Smog Society and Diary of an Interesting Year

The deterioration of the environment caused by climate change has been entangled with other factors to wane people’s desire for having children.This paper takes two climate short stories,The Smog Society by the Chinese SF author Chen Qiufan and Diary of an Interesting Year by the British writer Helen Simpson as case studies,comparing the writing of the climate change induced fertility anxiety in the two stories from both the individual and community perspectives.By associating the textual analysis with the social reality about fertility rate in China and Britain,the paper explores performance and coping methods of fertility anxiety in the face of climate crisis,aimed at providing possible solutions for the sustainable development of population.

The Characteristics of Changes in Sunshine Hours of Jimusi Region in Sanjiang Plain

Based on the data of sunshine hours from the four stations in Jiamusi region in Sanjiang Plain from 1961 to 2011, we analysed the changing tend and the abnormal year of sunshine hours in this region. The results showed that annual sunshine hours reduced extremely significantly in three stations of Jiamusi region in Sanjiang Plain in recent 50 years, especially in spring and winter, and the decrease of annual sunshine hours was the largest in the middle of Jiamusi region, followed by the west, while it was the smallest in the east. On the contrary, annual sunshine hours increased extremely significantly in Fuyuan in the northeast. Monthly sunshine hours of this area changed from 134.1 to 246.0 h, and the maximum data appeared in March, and the next was June, while the minimum one appeared in December. Total monthly sunshine hours reached the maximum in Tangyuan in the west, followed by middle Jiamusi and Fujin in the east, while the minimum appeared in Fuyuan in the northeast. Sunshine hours showed an increasing tendency only in July and August. From 2001 to 2011, annual sunshine hours showed a decreasing tendency in Jiamusi, while there was an obvious increase in Tangyuan, Fujin and Fuyuan; in the 20th century, annual average sunshine hours from the 1980s to 1990s decreased by 267.7 h compared with that from 1960s to 1970s. Among them, sunshine hours were the fewest in the 1990s. In recent 50 years, there was an abnormal increase in annual sunshine hours in Jiamusi in 1975 and 1982; while there were abnormal decreases in Tangyuan and Fujin in 1993, Fujin in 1995, and Fuyuan in 1982 and 1987.

Average Annual Temperature Changes in the Holocene in China

Abstract: In 1876 Blytt proposed a post-glacial climatic classification, maintaining that the then temperature fluctuated 1–2°C higher or lower than that today. Lamb (1969) held that in Europe “the axis of the subtropical high pressure belt was generally displaced north by about 10° latitudes” during the Hypsithermal and that the temperature was three to six times higher than that in the postglacial period.

Tibet's Dramatic Changes Over the Last 60 Years

The days when Wangdu was a serf are long gone, since democratic reform in Tibet in 1959 declared the endof serfdom there. However, he won fame and was remembered as Serf Champa.

Variations Trend of Soil Temperature at Deep Layers in Xining from 1961 to 2010

[Objective] The aim was to analyze the changes trend of mean earth temperature at 0.8, 1.6 and 3.2 m deep to the ground in Xining from 1961 to 2010. [Method] Using the data of monthly mean soil temperatures at 0.8,1.6 and 3.2 m in Xining from 1961 to 2010, the linear trend, climatic anomalous and climate abrupt of deep soil temperature during recent 50 years were analyzed by using of linear trend analysis, accumulated variance and signal noise ratio methods. [Result] In terms of linear trend, the annual mean soil temperatures at 0.8 m in recent 50 years, as well as 1.6 and 3.2 m in recent 45 years displayed a weak increasing trend in Xining. Comparing with the average air temperature in the same period, the rising range of deep soil temperature is obvious less. The average soil temperatures at 0.8 m was the highest in 1980s, but it was the lowest in the 1960s. In spring, autumn and winter in the 1980s, the average soil temperature was a little higher than many other years at 1.6 m. In four seasons in the 1980s, the average soil temperature was obvious higher at 3.2 m. The annual soil temperatures at 0.8 m were anomalous warm in 1991, and from 1987 to 1992, as well as in 1994, 2007 and 2009. The annual soil temperatures at 3.2 m were anomalous warm. In the 1990s, there were four years which were anomalous warm at 3.2 m, as well as five years at 0.8 m and five years at 1.6 m. [Conclusion] The study provided theoretical basis for the development of climate changes in Xining.

The Marine Dynamics and Changing Trend off the Modern Yellow River Mouth

Topography around the Yellow River mouth has changed greatly in recent years, but studies on the current state of ma- rine dynamics off the Yellow River mouth are relatively scarce. This paper uses a two-dimension numerical model(MIKE 21) to reveal the tidal and wave dynamics in 2012, and conducts comparative analysis of the changes from 1996 to 2012. The results show that M2 amphidromic point moved southeastward by 11 km. It further reveals that the tides around the Yellow River mouth are relatively stable due to the small variations in the tidal constituents. Over the study period, there is no noticeable change in the distribution of tidal types and tidal range, and the mean tidal range off the river mouth during the period studied is 0.5–1.1 m. However, the tidal currents changed greatly due to large change in topography. It is observed that the area with strong tidal currents shifted from the old river mouth(1976–1996) to the modern river mouth(1996–present). While the tidal current speeds decreased continually off the old river mouth, they increased off the modern river mouth. The Maximum Tidal Current Speed(MTCS) reached 1.4 m s-1, and the maximum current speed of 50-year return period reached 2.8 m s-1. Waves also changed greatly due to change in topography. The significant wave height(H1/3) of 50-year return period changed proportionately with the water depth, and the ratio of H1/3 to depth being 0.4–0.6. H1/3 of the 50-year return period in erosion zone increased continually with increasing water depth, and the rate of change varied between 0.06 and 0.07 m yr-1. Based on the results of this study, we infer that in the future, the modern river mouth will protrude gradually northward, while the erosion zone, comprising the old river mouth and area between the modern river mouth and the old river mouth(Intermediate region) will continue to erode. As the modern river mouth protrudes towards the sea, there will be a gradual increase in the current speed and decrease in wave height. Conversely, the old river mouth will retreat, with gradual decrease in current speed and increase in wave height. As more coastal constructions spring up around the Yellow River mouth in the future, we recommend that variation in hydrodynamics over time should be taken into consideration when designing such coastal constructions.

RECENT 200 YEARS CLIMATIC AND ENVIRONMENTAL RECORDS FROM THE FAR EAST RONGBUK ICE CORE, MT. QOMOLANGMA (EVEREST)

During the Sino\|American Expedition to Mt. Qomolangma in May 1997, a 41m ice core was recovered from an elevation of 6500m from the northern branch firn basin of the Far East Rongbuk Glacier in Mt. Everest. The ice core was dated down to 1814 by counting δ 18 O peaks and referring to the variations of β activity and major ion concentrations. The average annual accumulation is 224mm (ice equivalent). Five cold periods and five warm periods have been reconstructed from the ice core for the last 200 years and the general tendency of climatic change is warming, which is agree with the temperature change in the Northern Hemisphere. Also the climatic records in Far East Rongbuk ice core has good agreement with that in the Guliya ice core. This indicates that the climatic changes are consistent in the northwestern and southern Qinghai—Tibetan Plateau, and the ranges of climatic changes are larger in southern Plateau than that in northwestern Plateau. Though the δ 18 O variations has some negatively correlation with precipitation amount for short time scale, these do not effect δ 18 O changes reflecting temperature for long time scale.