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Private diaries are important sources of historical data for research on climate change. Their advantages include a high veracity and reliability, accurate time and location information, a high temporal resolution, seasonal integrity, and rich content. In particular, these data are suitable for reconstructing short-term, high-resolution climate series and extreme climatic events. Through a case study of Yunshan Diary, authored by Bi Guo of the Yuan dynasty of China, this article demonstrates how to delve into climate information in diaries, including species distribution records, phenological records, daily weather descriptions and personal experiences of meteorological conditions. In addition, this article considers how to use these records, supplemented by other data, to reconstruct climate change and extreme climatic events on various timescales, from multidecadal to annual or daily. The study of Yunshan Diary finds that there was a relatively low amount of precipitation in central and southern Jiangsu Province in the summer of 1309; the winter of 1308–1309 was abnormally cold in the Taihu Lake basin. In the early 14th century at the latest, the climate in eastern China had begun to turn cold, which reflects the transition from the Medieval Warm Period to the Little Ice Age.

To improve the accuracy of historical cropland data, we reconstructed cropland cover in the northern China’s farming–pastoral zone during the Liao dynasty using historical literature and settlement relics. We first reconstructed the total cropland area using historical household data based on the cropland area per household. Next, we allocated the cropland area into 5′ grid cells weighted by settlement density to generate a cropland data. Our main findings were as follows: (1) Data on settlement relics enabled not only the identification of ancient farming areas but also the allocation of cropland cover within high resolution grids in the study area. (2) In the flourishing period of the Liao dynasty, the total cropland area was 0.39 × 104 km2. The cropland grids comprised 28.30% of the total grids, with average and maximum values of cropland fractions of 6.61% and 31.18%, respectively. (3) Compared with our result, we found that the PJ overestimate the cropland area of the study area in 1100 AD, whereas the HYDE 3.2 underestimate it. The area of anthropogenic land use in KK 10 was larger than the cropland area in this study too. None of the three global datasets revealed the mosaic spatial distribution pattern of cropland cover in this study area. (4) The orders of land suitability for cultivation during the Liao dynasty and the present period were almost the identical, even in the farming–pastoral zone of northern China, which has fragile ecological environment.

To evaluate the climatic and ecological impacts of anthropogenic activities in global change research, it is essential to reconstruct historical land use and land cover change on regional and global scales. In this study, we reconstructed cropland areas for 54 provinces within the European part of Tsarist Russia (ETR) over the periods of 1696–1914 using historical data, including cropland area, population, grain consumption, and grain yield per unit area. The main results are as follows. (1) Total cropland areas and fractional cropland areas of ETR for 8 time sections during 1696–1914 were reconstructed, the former increased from 31.98×104 km2 to 147.40×104 km2, and the latter increased from 7.89% to 29.20%. The per capita cropland area decreased from 0.0246 km2 to 0.0113 km2 during 1696–1914. (2) Cropland expanded from the central and southwestern ETR to the black soil region, surrounding area of the Volga River, Ukraine region, the new Russia region, the vicinity of Ural, and north Caucasus region. (3) The expansion of territory, increase and migration of population, policies related to agricultural development and foreign trade, and the impacts of climate change were the reasons for the changes in cropland within ETR from 1696 to 1914. (4) In 1914, the cropland area and fractional cropland area of each province varied from 0.16×104 km2 and 0.76% to 5.65×104 km2 and 76.68%, respectively. (5) The comparisons show that the cropland areas of ETR in this study for 1696–1914 are higher than those in the HYDE 3.2 dataset. The main reason for this finding might be the underestimation of per capita cropland areas in the HYDE 3.2 dataset, which values remained at approximately 0.01 km2 from 1700 to 1920.

Land use-induced land cover change (LUCC) is an important anthropogenic driving force of global change that has influenced, and is still influencing, many aspects of regional and global environments. Accurate historical global land use/cover datasets are essential for a better understanding of the impacts of LUCC on global change. However, there are not only evident inconsistencies in current historical global land use/cover datasets, but inaccuracies in the data in these global dataset revealed by historical record-based reconstructed regional data throughout the world. A focus in historical LUCC and global change research relates to how the accuracy of historical global land cover datasets can be improved. A methodology for assessing the credibility of existing historical global land cover datasets that addresses temporal as well as spatial changes in the amount and distribution of land cover is therefore needed. Theoretically, the credibility of a global land cover dataset could be assessed by comparing similarities or differences in the data according to actual land cover data (the “true value”). However, it is extremely difficult to obtain historical evidence for assessing the credibility of historical global land cover datasets, which cannot be verified through field sampling like contemporary global land cover datasets. We proposed a methodological framework for assessing the credibility of global land cover datasets. Considering the types and characteristics of the available evidence used for assessments, we outlined four methodological approaches: (1) accuracy assessment based on regional quantitative reconstructed land cover data, (2) rationality assessment based on regional historical facts, (3) rationality assessment based on expertise, and (4) likelihood assessment based on the consistency of multiple datasets. These methods were illustrated through five case studies of credibility assessments of historical cropland cover data. This framework can also be applied in assessments of other land cover types, such as forest and grassland.

The Dongting Plain is an area characterized by wetland losses because of long-term polder construction. The study of historical polder expansion provides an opportunity to better understand the loss of wetlands covered by polders. To reconstruct the polder expansion over time, the polder patches extracted though remote sensing were marked with the names obtained from maps and the times of construction obtained from local gazetteers, and shown in the chronological order of turning points. Then, the distribution and changes in the wetlands covered by polders during 1368–1980 were reconstructed. The following are the major findings: (1) the current polders (2010s) accumulated over many centuries. There were 5.7% of the current polder area in 1644, 14.0% in 1735, 23.4% in 1850, 55.0% in 1911, 73.6% in 1949, and 100% in 1980; (2) the wetlands were mostly lost in the northern part of the region and declined rapidly over the past two centuries. The wetland area in 1850 was 6635 km2, which in 1911, 1949 and 1980 were 73.9%, 62.7% and 40.6% of that in 1850, respectively; (3) there were differences in the rate of wetland loss. The fastest time of wetland area disappearance was in 1949–1980, and 45.8 km2 of the wetlands had been lost each year; and (4) there was a spatial difference in wetland losses caused by polder expansion. In the northern part of the area, the wetland loss was mainly in 1851–1980, and the polders constructed in this period covered 89.5% of the polder area. In contrast, in the southern part of the area, the change in the wetland area was relatively small in each period, and the polder constructed before and after 1850 covered 48.3% and 52.7% of the polder area, respectively.

ENSO is an interannual mode which may be affected by external forcing, such as volcanic eruptions. Based on the reconstructed volcanic eruptions chronology and ENSO sequences, both 195 large volcanic eruptions (VEI≥4) and 398 ENSO (El Nino and La Nina) events were extracted from 1525 to 2000. An analysis of the correspondence between the large volcanic eruptions and ENSO events was performed by matching the large volcanic eruptions with the types and magnitudes of ENSO events present in the 0–2 years after the eruptions. The results show the following: (1) The percentages of ENSO events within the 3 years after the large eruptions had increased to 68.3% from 31.7% compared with those with no-eruptions in the previous 0–2 years. In addition, the ratio of El Nino to La Nina events turned from 2:3 to 1:1, and more El Nino events occurred in the 0 year after eruptions in the low-latitudes of the Northern Hemisphere and in the tropics but more La Nina events occurred in the 0 year after in the high-latitudes of the Northern Hemisphere and the Southern Hemisphere. (2) After the eruptions, the weak (W) El Nino events had increased by 8 percentage points and the very strong (VS) El Nino events had decreased by 10 percentage points; conversely, there was a decrease by 15 percentage points of the weak La Nina events and an increase by 11.4 percentage points of the very strong La Nina events. Specifically, the percentages of strong La Nina events increased to a peak at 1 (+1) year after the eruptions. (3) The percentage of eruptions followed by single-year ENSO was the greatest. The percentage of ENSO events that occurred in the consecutive 2 years following an eruption was approximately equal to the percentage of events that occurred consecutively 3 years following an eruption, and both sets of ENSO magnitudes showed a decreasing trend.

Global historical cropland datasets allocate cropland areas into grids above on the assumption that land suitable for crops is similar to that in the present or changeless over time. However, land suitability has changed over time. The Dongting Plain, which is full of polders, is characterized by changing land suitability for crops over the past 300 years and provides a case study of the impact of changing land suitability on spatially explicit reconstructions. Here, cropland areas were reconstructed at the county level and allocated into grids at 0.5′ × 0.5′. This allocation was based on the expansion of polders, which indicated land suitable for crops. The results showed the following: (1) The land suitable for crops constituted 68.24% of the total area in 1750 and it expanded after 1850, which in 1911, 1949, and 1985 was 1.10, 1.18, and 1.25 times that of 1750, respectively. (2) The regional cropland area fraction was 21.60% in 1750 and it increased after 1850, which in 1911, 1949, and 1985 was 127.21%, 140.27%, and 156.03% that of 1750. (3) The grids with cropland fractions increased due to polder development by more than 30% in the middle of the region from 1750 to 1985, occupying 32.16% of the total grids. (4) Changes in the land suitability for crops impacted the spatially explicit reconstruction. The grids unsuitable for crops were 78, 46, and 28 in 1850, 1911, and 1949 at 0.5′ × 0.5′, which constituted 19.21%, 11.33%, and 6.90% of the total grids, respectively. In comparison with this study, some of the grids unsuitable for crops were allocated as cropland by HYDE 3.2 and covered 93.59%, 89.13%, and 82.14% of the total unsuitable girds.

Graphene platelet networks (GPNs) were deposited onto silicon substrates by means of anodic arc discharge ignited between two graphite electrodes. Substrate temperature and pressure of helium atmosphere were optimized for the production of the carbon nanomaterials. The samples were modified or destroyed with different methods to mimic typical environments responsible of severe surface degradation. The emulated conditions were performed by four surface treatments, namely thermal oxidation, substrate overheating, exposition to glow discharge, and metal coating due to arc plasma. In the next step, the samples were regenerated on the same substrates with identical deposition technique. Damaging and re-growth of GPN samples were systematically characterized by scanning electron microscopy and Raman spectroscopy. The full regeneration of the structural and morphological properties of the samples has proven that this healing method by arc plasma is adequate for restoring the functionality of 2D nanostructures exposed to harsh environments.

Case studies on the impacts of extreme weather events at different spatial and temporal resolutions can help further the understanding of the impacts of climate change and serve as references for coping with future climate change challenges as well. We reconstructed the monthly time series data on social impacts of an extreme drought event in the Guanzhong area, Shaanxi Province, China, using newspaper records from 1928 to 1931. Changes in food substitutions, food prices, social unrest, and social resilience are analyzed to show how the drought affected the area. The results show that (1) the evolution of social impacts of the drought can be divided into five stages, and the variation in the impact magnitude is strongly influenced by the summer and autumn harvests; (2) the cumulative effects of the persistent drought are observed, and the level of social resilience declined rapidly and nonlinearly; and (3) there are two kinds of spreading patterns of drought’s impacts across natural, supporting, and humanity systems: hierarchical propagation and cascading effects. They act over different spatial and/or temporal scales and could provide the inspiration for the strategies designed to mitigate the impacts of climate change and extreme weather events today.

The North China Famine of 1876&ndash, 1879, known in Chinese as the Dingwu qihuang (丁戊奇荒), is a famous case of drought-induced famine in Chinese history. The purpose of this paper is to provide empirical and historical evidence for understanding the impacts of extreme climate events and major disasters and the mechanisms of adaptation. From the aspects of famine-related migration and the allocation of relief money and grain, the regional interactions in social responses to extreme climate events were analyzed. This paper collected 186 records from historical documents. Regarding the regions as the nodes and the relationships between regions as the links, the spatial patterns of famine-related migration and the allocation of money and grain from 1877 to 1878 were rebuilt. The results show that, firstly, famine-related migration appeared to be spontaneous and short-distanced, with the flow mainly spreading to the surrounding areas and towns. Secondly, as a state administrative action, the relief money and grain from the non-disaster areas were distributed to the disaster areas. However, the distribution of relief grain affected the equilibrium of the food market in non-disaster areas, which led to fluctuations in food prices.

Modern global cropland products have been widely used to assess the impact of land use and cover change (LUCC) on carbon budgets, climate change, terrestrial ecosystems, etc. However, each product has its own uncertainty, and inconsistencies exist among different products. Understanding the reliability of these datasets is essential for knowing the uncertainties that exist in the study of global change impact forced by cropland reclamation. In this paper, we propose a set of coincidence assessments to identify where reliable cropland distribution is by overlaying ten widely used global land cover/cropland datasets around 2000 AD. A quantitative assessment for different spatial units is also performed. We further discuss the spatial distribution characteristics of different coincidence degrees and explain the reasons. The results show that the high-coincidence proportion is only 40.5% around the world, and the moderate-coincidence and low-coincidence proportion is 18.4% and 41.1%, respectively. The coincidence degrees among different continents and countries have large discrepancies. The coincidence is relatively higher in Europe, South Asia and North America, while it is very poor in Latin America and Africa. The spatial distribution of high and moderate coincidence roughly corresponds to the regions with suitable agricultural conditions and intensive reclamation. In addition to the random factors such as the product&rsquo, s quality and the year it represented, the low coincidence is mainly caused by the inconsistent land cover classification systems and the recognition capability of cropland pixels with low fractions in different products.

Grain price volatility during historical periods is regarded as an important indicator of the impact of climate change on economic system, as well as a key link to adjust food security and social stability. The present study used the wheat prices in Baoding Prefecture, China, during 1736-1850 to explore connections between climatic transition and grain price anomalies in the North China Plain. The main findings were as follows: (1) The grain price change showed an apparent correspondence with climatic transition. The period 1781-1820 was a transition phase, with more extremes and decreased precipitations when the climate shifted from a warm phase to a cold one. Corresponding with the climatic transition, the grain price during 1781-1820 was characterized by that the mean of the original grain price series was significantly higher (lower) than the previous (later) phase, and the variance and anomaly amplitude of the detrended grain price series was the highest during 1736-1850. (2) The correspondence between grain price extremes and drought events occurred in phases. Five grain price extremes occurred following drought events during 1781-1810, while extreme droughts were the direct cause of the grain price spike during 1811-1820. (3) Social stability affected by climate change also played an important role in the grain price spike between 1811 and 1820. Paralleling the pathway of "precipitation-grain production-grain price", climate change could have an impact on grain price via the pathway of "precipitation-grain production-grain price-famine-uprising-grain price", as shown during the Tianli Uprising in 1813. These findings could contribute to an improved understanding of the interaction between climate change and human society during the historical period.

There are still many uncertainties about how climate change affects the development of human society. The impact of climate change is likely to be weakened or amplified by the response and adaptation of the reciprocal feedback process after entering the socio-economical subsystem. The study of the climate change impact processes is the basis for understanding the mechanisms of climate change impacts. Furthermore, long-term research of climate change impacts can provide historical similarity and experience for current or future adaptation of climate change. Ancient China was traditionally an agricultural country. Its food production safety, food supply safety, and food consumption safety reflect the impacts of climate change being transferred from a production subsystem to a population subsystem to an economic subsystem. Based on a conceptual framework of food security, we selected 10-year resolution sequences of grain harvest grades, famine indices, and economic levels in China over the past 2000 years (206 BC–AD 1911) to quantify and recognize the main transmission pathways of climate change impacts during cold and warm units of climate change. Our results were as follows: (1) according to the transmission relationship climate change → grain harvests → famines → economic levels, there are 16 main transmission pathways, including 10 pathways starting from cold units and 6 pathways starting from warm units. (2) The main pathway is dominated by natural factors and socio-economic factors, with each factor set accounting for approximately 50%. However, the probability of the main pathways with socio-economic influence leading toward negative developments was 60% for cold units, and the probability of the main pathways with socio-economic influence leading toward positive developments was 66.7% for warm units. According to the main pathway led by natural factors, of all transmission pathways in cold units (100%), 14.7% of the depressed economy may be more directly related to climate change. However, 32.3% of the prosperous economy may have a more direct relationship with climate change in warm units (100%). (3) Famine is the most important link in the climate change influence on transmission chains regulated by socio-economic factors. Famine reflects both poor harvests due to the natural production subsystem and a lack of grain allocation by the socio-economic subsystem or the government’s ability to eliminate famine. Thus, there may be another pathway of transmission, such as climate change → agricultural yield/grain production → economic prosperity → famine relief (social vulnerability).

The present study aims to compare quantitatively the similarities and differences of transmission processes extending from climate change to grain harvests and economies (macro-economy and fiscal balance) between the Han (206 BC–AD 220) and Tang (AD 618–907) dynasties of China. It is found that both the Han and Tang periods displayed close positive correlations among temperature, grain harvest, macro-economy and fiscal balance and conveyed a positive feedback–oriented transmission pattern with the upgrade of climatic impact level from grain harvest to economic system. Compared with the Han period, the overall linkages among indicators weakened during the Tang period, particularly for the correlation between grain harvest and fiscal balance. The mean temperature during the Tang period was slightly higher but had greater multidecadal variability, coinciding with better performance (and less variations) of macro-economy and fiscal balance (particularly for cold units) and higher variations of grain harvest. It displayed relatively little difference for the main pathways that could be interpreted as climatic impacts during the warm units between the Han and Tang periods, and both approximately 33% of the decades for warm units (100%) ending with fiscal balance/surplus were more likely to be associated with the impacts of temperature change. The difference mainly lies in cold units in the links of ‘cold → poor harvest’ and ‘poor harvest → macro-economic depression’ through the pathway of ‘cold → poor harvest → macro-economic depression/normal economy → fiscal deficiency’. Overall, macro-economy and fiscal system of the Tang period displayed less sensitivity to temperature change and agriculture production in cold period. Those patterns might be related with the unique socio-economic situations such as agricultural fragmentation, southward shift of economic resource and tax system reform during the later Tang Dynasty.

By merging reconstructed phenological series from published articles and observations of China Phenology Observation Network (CPON), the first blooming date of Amygdalus davidiana (FBA) in Beijing between 1741 and 2000 is reconstructed. The Butterworth method is used to remove the multi-year variations for generating the phenological series of annual variations in the first blooming date of A. davidiana. The extreme delay years in the phenological series are identified using the percentage threshold method. The characteristics of the extreme delays and the correspondence of these events with natural forcings are analysed. The main results are as follows. In annual phenological series, the extreme delays appeared in single year as main feature, only A.D.1800-1801, 1816-1817 and 1983-1984 were the events of two consecutively extreme years. Approximately 85% of the extreme delays occurred during 1-2 years after the large volcanic eruptions (VEI ≥ 4) in the eastern rim or the western rim of the Pacific Ocean, as the same proportion of the extreme delays followed El Niño events. About 73% years of the extreme delays fall in the valleys of sunspot cycles or the Dalton minimum period in the year or the previous year. According to the certainty factor (CF), the large eruptions have the greatest influence to the extreme delays; sunspot activity is the second, and ENSO is the last one. The extreme phenological delayed year is most likely to occur after a large eruption, which particularly occurs during El Niño year and its previous several years were in the descending portion or valley of sunspot phase.

Relic archeological settlement is used to indicate the development of agriculture. We extracted 8865 relic archeological settlements from theAtlas of Chinese Cultural Relicsto analyze how the spatiotemporal distribution of archaeological settlements was influenced by temperature changes and social factors during the last millennium. During the Liao dynasty (AD 916–1125) and Jin dynasty (AD 1115–1234) in the Medieval Warm Period (MWP), a large number of settlements indicated the development of agriculture as far north as 47°N. The warm climate of the MWP provided sufficient heat resources to promote the implication of positive policies of the Liao and Jin dynasties to develop agriculture and settlements. By contrast, during the dynasties of Yuan (AD 1279–1368), Ming (AD 1368–1644), and Qing (AD 1644–1911) in the Little Ice Age (LIA), the number of settlements declined drastically, and the northern boundary of the settlement distribution retreated by 3–4 degrees of latitude to modern Liaoning Province. Although the southward retreat of the settlements and related agriculture occurred in the cold climate of the LIA, it could not be completely explained by the drop in temperature. Social factors including nomadic customs, ethnic policies, and postal road systems played more important roles to the northern boundaries of the settlement distributions during the Yuan, Ming, and Qing dynasties.

As a direct result of climate change and extreme weather events, refugee migration has attracted worldwide concern. In this study, we select the North China Plain (NCP) as the case area, where the capital (Beijing) is located during the late Qing dynasty (1790–1911). Based on records of porridge charity, public order (inside Beijing), and revolt events (outside Beijing) in ancient official documents, the interaction between behavior of refugees and the governmental management after floods and droughts is analyzed. The main conclusions can be summarized as follows. (1) Flood/drought has become an important triggering factor of refugee migration during 1790–1911 besides the social factors (e.g., man-land contradiction, fiscal crisis). (2) A negative interaction has existed between the government and refugees throughout the late nineteenth century, which leads to social disorder in the mid-1890s in Beijing and large-scale revolt (the Boxers Movement) in 1900 in the NCP. (3) The negative interaction has been finally ended by the adjustment of migration policy at the beginning of the twentieth century, which officially permits the refugees from the NCP to emigrate to Manchuria and Mongolia outside the Great Wall. The historical case study may provide valuable lessons for the successful adaptation of human societies to future similar occurrences, and will enhance our understanding of the interactions between climate change and social vulnerability.

A novel highly controllable process of Carbon Encapsulated Magnetic Nanoparticles (CEMNs) synthesis in arc discharge plasma has been developed. In this work, both the size distribution and the purity of the CEMNs have been made more controllable by adding an external magnetic field. It is shown that with the increase of the external magnetic field, the CEMNs get a better separation from the carbon impurities and the size distribution become narrower. This conclusion is valid for Fe, Ni and Fe+Ni CEMNs synthesis. In order to assess biomedical potential of these CEMNs, the cytotoxicity has also been measured for the human breast adenocarcinoma cell line MDA-MB-231. It was concluded that the CEMNs with the concentration in cell of about 0.0001-0.01ug/ml are not toxic.

The study on the relationship of abandoned settlements and climate change in the oases could provide a historical reference for understanding human responses to present and future global warming in the arid zone. A total of 554 abandoned historical settlements in Xinjiang Uygur Autonomous Region, China, were used to examine the relationship between abandoned settlements and temperature change over the past 2000 years. The analysis covered dynastic epochs from the Han Dynasty (206BC–220AD) to the Qing Dynasty (1644AD–1911AD) in the oases of Xinjiang. Greater density of settlements was found at the oases larger than 2000 km2, which were more stable and less sensitive to climate change compared to smaller oases. Settlements flourished at small oases and the middle and lower reaches of rivers during warm periods and shrank back to piedmont basins and upstream alluvial fans during cold periods. These results demonstrated responses of oasis agriculture to climate change.

In this study, 89 records of spring phenophases of plants and lake melting dates in Beijing from A.D. 1741 to 1832 were extracted from the poems written by the Qianlong, Jiaqing, and Daoguang emperors during the Qing Dynasty. Based on a phenology transformation model, all of these spring phenological records were converted into the first blooming date of Amygdalus davidiana for A.D. 1741–1832. Then, a springtime temperature anomaly series for A.D. 1741–1832 was reconstructed based on modern (1951–1980) correlation between the first blooming date of A. davidiana and the mean springtime (March–May) temperature. The main results are as follows. (1) The spring phenological and temperature series for Beijing were successfully dated back to A.D. 1741. (2) A.D. 1790 was the turning point of the spring phenology change between 1741 and 1832; specifically, the average first blooming date of A. davidiana had advanced by 4.84 days compared to the present (A.D. 1951–1980), during 1741 to 1789, and was delayed by 0.14 days during 1790 to 1832. (3) The mean springtime temperature in A.D. 1741–1789 was about 0.48 °C warmer than the present (A.D. 1951–1980) in Beijing. (4) The annual-scale variation of the phenological series during A.D. 1790–1832 was greater than that in A.D. 1741–1789.

Articular cartilage repair and regeneration are a challenging problem worldwide due to the extremely weak inherent regenerative capacity of cartilaginous tissue. As an emerging tissue engineering scaffold fabrication technology, 3D bioprinting has shown great promise in fabricating customizable artificial tissue matrices with hierarchical structures. The goal of the present study is to investigate 3D bioprinted graphene oxide (GO)-doped gelatin–based scaffolds for promoting chondrogenic differentiation of human bone marrow mesenchymal stem cells (MSCs). In the current study, GO-gelatin methacrylate (GelMA)–poly (ethylene glycol) diacrylate (PEGDA) was prepared as a biocompatible photopolymerizable bioink. GO, a multifunctional carbon based nanomaterial, was incorporated into the bioink for promoting chondrogenic differentiation. Finally, the 3D printed GelMA-PEGDA-GO scaffold with hierarchical structures was fabricated via our novel table-top stereolithography-based printer. Results showed that GelMA-PEGDA-GO scaffolds greatly promoted the glycosaminoglycan, and collagen levels after GO induced chondrogenic differentiation of hMSCs. Moreover, the Collagen II, SOX 9, and Aggrecan gene expressions associated with chondrogenesis were greatly promoted on the scaffolds. This study demonstrated that customizable 3D printed GelMA-PEGDA-GO scaffolds are excellent candidates for promoting chondrogenic differentiation of hMSCs and are therefore promising candidates for future cartilage regenerative medicine applications.

This study is intended to investigate the patterns for the temporal and spatial changes of catastrophic river floodings which took place in the Lower Yellow River, based on the available records collected from historical documents, and rearranged in a GIS database. A series of catastrophic river floodings from AD 960 to 1938 was reconstructed, and their temporal and spatial variations were analyzed, which leads to the conclusions, among others. (1) The increasing trend of frequency of catastrophic river floodings in the Lower Yellow River is not so significant in the past 1000 years. (2) Most dike breachings and overtoppings occurred near the apex of the Yellow River Alluvial Fan, and the number of dike breaching and overtopping was gradually reduced as the elevation decreased. (3) Under different spatio-temporal backgrounds, dike breaching and overtopping developed either downstream or upstream, which is evidenced by both the downstream movement for large temporal and spatial scales in dike breaching and overtopping places in AD 1128–1344 and 1391–1447 and the upstream movement for small temporal and spatial scales in AD 960–969, 1730–1761, and 1807–1819.

Arc discharge is one of the most efficient and environmental friendly method to synthesize Single Wall Carbon Nanotube (SWCNT). However, due to the ultra-fast synthesis procedure, localization of the SWCNT synthesis in an arc discharge plasma volume in situ has been a long standing problem. This relates to the ability of controlling volumetric synthesis of nanostructures in plasmas in general. In order to better understand the mechanism of the nanotube growth in plasma, we have developed an actuator driven high-speed system that is able to extract material from the arc plasma volume during the synthesis procedure. The majority of the SWCNTs produced using arc discharge method are semiconducting with diameter of about 1.5 nm. It is shown that the growth region of SWCNTs is between 3 mm and 11 mm away from the center of the arc discharge. Dependent on the origin, the length of SWCNTs increases non-monotonically up to 500 nm, while diameter and chirality only slightly depend on the growth position.

The quality of global cropland products could affect our understanding of the impacts of cropland reclamation on global changes. With the advancement of remote sensing technology, several global land cover products and synergistic datasets have been developed in recent decades. However, there are still some disagreements among the global cropland datasets. In this paper, we proposed a new synergistic method that integrates the reliability of spatial distribution and cropland fraction on a pixel scale, and developed a modern (around 2000 C.E.) fractional cropland dataset with a 1 km × 1 km spatial resolution on the basis of the spatial consistency of cropland reclamation intensity derived from multi-sets of global land cover products. The main conclusions are shown as follows: (1) The accuracy of spatial distribution assessed by validation samples in this synergistic dataset reaches 87.6%, and the dataset also has a moderate amount of cropland pixels when compared with other products. (2) The reliability of cropland fraction on the pixel scale had been highly improved, and most cropland pixel has a higher fraction (over 90%) in this dataset. The “L” shape of the histogram of pixel numbers with different reclamation intensities is reasonable because it is consistent with the up-scaling results derived from satellite-derived products with high spatial resolutions and the expert knowledge on cultivation. (3) The cropland areas in this non-calibrated result are generally closer to that of FAOSTAT on scales from global to national when compared to other non-calibrated synergistic datasets and original satellite-derived products. (4) The reliability of the synergistic result developed by this method might be decreased to some degree in the regions with high discrepancies among the original multi-sets of cropland datasets.

Continuous detection of dispersion and residence of volcanic plumes in troposphere and lower stratosphere is vitally important for improving the understanding on the role of volcano eruptions in climate change. We report a 3-month continuous detection of dispersion and residence of volcanic plumes in the troposphere and stratosphere generated from the volcanic SO2 erupted by Nabro in Eritrea on June 12th, 2011 observed by the OMI sensor. The background SO2 concentration of 3 different height layers in troposphere and lower stratosphere were estimated by the 3-year-average daily concentration of monthly SO2 in 2005, 2007 and 2013, when there were no large explosive volcanic eruptions occurring. We also traced the diffusion path and the concentration of volcanic SO2 for the first 3 months after Nabro's eruption, and detected the appearance and dissipation of sulfate aerosols, which is a product converted from volcanic SO2. The results show that after Nabro erupted on June 12th, the volcanic plumes spread to middle latitudes (30 degrees N -60 degrees N) of Northern Hemisphere and loading by westerly jet. The volcanic SO2 in middle troposphere layer (TRM) and lower troposphere layer (TRL) stopped eastward spreading, and dissipated over the western Pacific Ocean on June 23rd. On June 26th, the volcanic SO2 in upper troposphere and lower stratosphere (STL) reached Mexico in Central America, and almost encircled the low latitudes and parts of middle latitudes. On June 28th, the volcanic SO2 plume showed an even distribution in STL. 37 days after the eruption, the volcanic SO2 in STL encircled the Northern Hemisphere evenly, sulfate aerosols in STL largely covered the low and middle latitudes and the daily concentration of SO2 was still higher than the background value. One month after the eruption, the global mean daily concentration of SO2 dropped to the normal value, but the daily concentration of SO2 and sulfate aerosols in low latitudes remained high, and dissipated not earlier than 3 months after the eruption of Nabro.

To better understand the process of land reclamation in the Dongting Plain (DTP), this paper reconstructed the spatiotemporal distribution of polders in the area. The images of polder patches were extracted from Google Earth using visual interpretation, and the corresponding polder names and times of polder construction were extracted from maps and local gazetteers. Moreover, this paper examined the possible relationships between the spatiotemporal distribution of polders and the regional environment change and socio-economic history. The results showed that: (1) The total area occupied by modern polders (in the 2010s) is 9703.18 km2, and the area was constructed in six stages that constituted 5.73% of the modern total area in 1368–1644, 8.29% in 1644–1735, 9.33% in 1736–1850, 31.71% in 1851–1911, 18.51% in 1912–1949, and 26.41% in 1949–1980. (2) In terms of the spatial distribution of polders constructed at each stage, the polders in 1368–1644 were predominately located in the northern DTP, and polders in 1644–1735 and 1736–1850 were predominately located in the south. Owing to the formation of the Ouchi River and the Songzi River, the new polders were constructed along the rivers in the central plain in the last three stages after 1850. (3) Multi-factors played distinctive roles in the construction of polders in different stages. The location affected the initial spatial distribution of polders in the mid-14th century. In the long run, the growth in population contributed to the increase of polders. The Four Rivers mainly affected the spatial distribution of polders in the south part of the DTP before 1850, and the four channels of the Yangtze River mainly affected polders in the north-central part of the DTP after 1850. The polders along the Xiang and Zi Rivers were cumulatively constructed and formed in multiple stages. The polders were constructed in the period from 1368 to 1850, and area accounted for 57.82% of polders along rivers. The polders along the four channels of the Yangtze River were a gradual development with continuous expansion, and the polder area in 1850–1980 was 92.40%.

The relation between climate change and historical rhythms has long been discussed. However, this type of study still faces the lack of high-resolution data concerning long-term socio-economic processes. In this study, we collected 1586 items of direct and proffered evidence from 29 Chinese history books. We used semantic analysis to reconstruct a quantitative series of the social vicissitudes of the past 2000 yr with a 10-yr resolution to express the phase transition of the social vicissitudes of the dynasties in China. Our reconstruction demonstrates that social vicissitudes have clear cyclical features on multiple time scales. Analysis of the association of social rise and fall with climate change indicates that temperature displayed more significant effects on social vicissitudes in the long term, while precipitation displayed more significant effects on the social vicissitudes in the short term. There are great overlaps between social and climatic variables around the predominant or periodic bands. Social rise mostly occurred in the centennial-scale warm periods, whereas social decline mostly occurred in the centennial-scale cold periods. Under warm-wet conditions, social rise occurred over 57% of the time; under cold-dry conditions, the social decline occurred over 66% of the time.

The social impacts of climate change constitute an important field within the study of global change. The impacts of historical climate change on dynastic transitions and prosperity in China from a food safety perspective is a helpful research topic that contributes to a better understanding of the impacts, process, and mechanism of climate change, as well as a reference for projecting the impacts of climate change in the future. This study defined the periods of dynastic transitions and prosperity in China from 210 BC to AD 1910 and analyzed the relationships among dynastic transition or dynastic prosperity, climate change, and grain harvests. From 210 BC to AD 1910, dynastic transitions mostly coincided with cold ages or the periods that changed from warm to cold and dry or wet-to-dry periods when there was relatively poor harvest. In contrast, dynastic prosperity mostly coincided with warm ages or the periods that changed from cold to warm and wet or dry-to-wet periods when there was relatively bumper harvest. Meanwhile, the dynastic transitions from a divisive dynasty to a unified dynasty often came with a progressively warm phase on the century scale when grain harvests increased. Interestingly, the division of a unified dynasty often came with a progressively cold phase and poor harvests. Furthermore, changes in temperature and agricultural production may be one of the most important factors leading to the collapse of Tang Dynasty. In conclusion, the fluctuation of grain harvests and climate change correspond with the transitions between a tumultuous society and an ordered one, which reveals that the social sensitivity periods were often a result of a change to a colder climate on the century scale.

Land-use and land-cover change (LUCC) has strongly influenced the global and regional climate and environmental change, especially over the last three centuries. Accurate reconstruction of historical LUCC is a key step for assessing the impact of LUCC on global environmental change. To fill in the gap of regional historical cropland reconstruction in North China and achieve a better understanding of the historical cropland change process, in this paper we reconstruct cropland change at the county level over the past 300 years in the Jing-Jin-Ji (Beijing–Tianjin–Hebei) area, China. The reconstruction is based on sources including gazetteers, statistics and survey documents, and the methods are composed of data calibration, data interpolation and correlation analysis of data. The results show that the cropland change in the Jing-Jin-Ji area fluctuated, which can be classified into five stages: rapid increase in 1677–1755 and 1916–1950, slight growth in 1755–1884, gentle decline in 1884–1916 and rapid decrease after 1950. Two peak values appeared in 1884 and 1950. The spatial distribution of cropland in the Jing-Jin-Ji area kept a steady expansion and the majority of cropland concentrated on the plain before 1911. After this, the spatial distribution of cropland became more even and there was a rapid increase in the eastern coastal region and the northern hilly region. After 1985, the Jing-Jin-Ji area has experienced rapid urbanization and cultivation ratios in most counties declined, especially in Beijing municipality. Our dataset of the cropland area at the county level can contribute to improving the precision of the global and national land-use and land-cover datasets.

In ancient China, shifts in regional productivity of agriculture and animal husbandry, caused by climate change, either led to wars or peaceful relations between nomadic and farming groups. During the period spanning the Western Han Dynasty to the Tang Dynasty, 367 wars were waged between these groups. While 69 % of the wars were initiated by nomads, 62.4 % were won by the farming groups. On a centennial timescale, the battlegrounds were mostly in northern areas (at an average latitude of 38.92° N) during warm periods, moving southward (at an average latitude of 34.66° N) during cold periods. On a decadal timescale, warm climates corresponded to a high incidence of wars (a correlation coefficient of 0.293). While farming groups were inclined to initiate wars during dry and cold periods, their chances of achieving victory were reduced at such times. The main reasons for this are, first, that a warm climate provided a solid material foundation for nomadic and farming groups, contributing especially to enhanced productivity among the former. However, the overriding desire of nomadic groups to expand essential subsistence means led to wars. Second, during cold periods, farming groups moved to and settled in the south, while nomadic groups occupied the Central Plain. Thus, the locations of the battlefields also changed. While other factors also influenced these wars, climate change served as a backdrop, playing an indirect role in wars between these groups.

Investigations of the relationships between climate and human history often place more emphasis on the science of climate change than on understanding human socio-economic processes, and therefore suffer from superficial results and an unbalanced perspective. This is partly due to the lack of high-resolution data concerning long-term socio-economic processes. Here, we base our study of climate and society on a series of 2130-yr-long economic proxy data from China with decadal resolution. The economy was associated significantly with temperature and precipitation at the two predominant bands of 100 and 320 yr. The phase transition of economic states was influenced positively by long-term temperature change combined with triggering effects of short-term changes in precipitation. However, climatic impact on economy should not be recognized as simple causality but some driving-response relation coupled with meditation by human agency at multiple scales. A model of ‘adaptive cycles’ implies, in relative to the developing phases, climate–economy relationship during the declining phases was more easily moderated by slower processes like rigidity and faster processes like unrest. From a more-macro perspective, climatic driving for the macro-economic cycles was moderated by larger and slower processes like social memory, spatial shifting of key economic areas, and social–technical advance.

Cropland area per capita and pressure index on cropland are important parameters for measuring the social vulnerability and sustainability from the perspective of food security in a certain region in China during the historical periods. This study reconstructed the change in spatial distribution of cropland area per labor/household and pressure index on cropland during the 17th–20th century by using historical documents, regression analysis, pressure index model, and GIS (geographic information system). Following this, we analyzed the impacting process of climate change and sustainability of cropland use during the different periods. The conclusions of this study are as follows: (i) there was an obvious spatial difference of labor/household density, as there was higher density in three agricultural areas, which had the same pattern as cropland distribution during the same periods; (ii) Cropland area per capita was relatively higher during the 17th–18th century, which were above 0.4 ha/person in the majority of counties and were distributed homogenously. Until the 19th century and the beginning of 20th century, cropland area per capita in a considerable proportion of regions decreased below 0.2 ha/person, which embodies the increase in social vulnerability and unsustainability at that time; (iii) The pressure index on cropland also showed a spatial pattern similar to cropland area per capita, which presented as having a lower threshold than nowadays. During the 17th–18th century, there was no pressure on cropland. In comparison, in the 19th century and at the beginning of 20th century, two high-value centers of pressure index on cropland appeared in the Middle Shandong and the Jiaodong region. As a result, pressure on cropland use increased and a food crisis was likely to have been created; (iv) A higher extent of sustainable cropland use corresponded to the cold period, while a lower extent of sustainable cropland use corresponded to the warm period in Shandong over the past 300 years. The turning point of the 1680s from dry to wet was not distinctively attributed to the decrease in the extent of sustainable cropland use in Shandong. Since the beginning of the 20th century, the increasing pressure on the sustainability of cropland use finally intensified the social conflict and increased the probability of social revolts.

The breakdown mechanism in the Micro-Cathode Arc Thruster has been studied to better understand the nature of the discharge ignition and to extend the ignition system lifetime. It has been found that optimal material selection of the insulator is an important factor during breakdown. Two opposite processes have been found to cycle during operation. The processes are degradation of the conductive film from the inter-electrode interface and re-deposition of the conductive film due to cathode spot erosion. Initial resistances were found to vary from hundreds of ohms to thousands of ohms based on the initial connectivity of the film to the electrodes. After initial breakdown however, resistances have been found to stabilize in a typical pattern. Materials capable of withstanding high temperatures, high pressures, and smooth surfaces are shown to be beneficial for extending thruster lifetime.

Background The process of human response to natural disasters and its mechanisms as revealed by historical events still has a broad significance for modern society. This study analyzed the disaster relief process and the social response for two floods in China: the Yongding River flood in 1801 and the Yellow River flood in 1841. These two floods reflect the different response processes between the national and provincial capitals during a stage of climate cooling and social transition in the Qing dynasty. Results Applying methods of historical documents analysis and qualitatively comparative analysis to the materials such as Relief Chronicles Authorized by the Emperor in XinYou and Flood Description in Bian Liang, it shows that: (1) In 1801, the central government took on a lead position, from flood surveying to relief processes. However, local government and gentries played an important role in 1841. (2) In 1801, the government successfully undertook a series of relief measures addressing production, housing, food prices, taxes, and water conservancy and administration. In 1841, the response measures were relatively simple, focusing mainly on providing shelter and food for victims. (3) The government carried out long-term disaster prevention measures such as dredging channels after the flood in 1801. In 1841, however, the efforts were focused mainly on emergency rescue. (4) Refugees in the 1801 flood were effectively managed by a centralized authority. In 1841, regulation of the flooding was delayed by corruption and conflicts between officers, leading to an expansion of the disaster’s impact. Conclusions Above results have led to the conclusion that disaster relief systems and response measures had a significant effect on the consequences of those floods. Various flood relief measures and natural disasters management regimes have implications for contemporary flood hazard mitigation.