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To address the 2-degree target, rapid decarbonization for China's power sector would be essential in the coming decades. This paper attempts to assess the impact of early and delayed mitigation efforts for China's power sector with the application of China TIMES model. With the introduction of carbon budget, CO2 mitigation pathways and corresponding energy transition routes have been generated through scenario runs, then mitigation potential and key challenges of the power sector have been analyzed. The key findings are the following: (1) in both early and delayed 2-degree scenarios, the power sector is expected to achieve negative emissions by mid-century, and over 60% of cumulative CO2 mitigation is required comparing with current policies scenario; (2) in addition to the promotion of new and renewable energy, rapid phase-out of coal-fired power plants and the deployment of biomass CCS technology would also be essential to achieve the 2-degree target; (3) recent investment in new coal-fired plants could cause carbon lock-in in the long term, over 1000 GW of plants may be early retired during 2030–2050, leading to great economic losses; (4) the deployment of biomass CCS technology plays a vital role in meeting the severe mitigation challenge, in early and delayed 2-degree scenarios, a total of 9.9 and 11.7 Gt of negative emissions could be achieved respectively from 2010 to 2050. [ABSTRACT FROM AUTHOR]

This paper deals with climate change and nomadic migration relationships at a long-term and wide geographical scale using a statistical approach in the vein of Bai and Kung (Rev Econ Stat 93:970–981 2011). More precisely, it presents a reassessment of these relationships in a nonlinear world using threshold regressions, time varying-copula, and nonlinear causality tests. The large amount of historical records in China enables us to re-interpret the link between climate and historical social dynamics (Hsiang et al., Science 341:1235367 2013) through different regimes of temperature and precipitation. Our nonlinear results have confirmed the role of climatic factors on migration. However, we find that climatic factors have affected the migration flows only during some sub-periods (especially 300–500 AD and 1050–1300 AD). As a consequence, the importance of the precipitation effect on migration has probably been slightly overestimated whereas the role of temperature anomalies has been underestimated. [ABSTRACT FROM AUTHOR]

The current nationally determined contributions, pledged by the countries under the Paris Agreement, are far from limiting climate change to below 2 ∘C temperature increase by the end of the century. The necessary ratcheting up of climate policy is projected to come with a wide array of additional benefits, in particular a reduction of today's 4.5 million annual premature deaths due to poor air quality. This paper therefore addresses the question how climate policy and air pollution–related health impacts interplay until 2050 by developing a comprehensive global modeling framework along the cause and effect chain of air pollution–induced social costs. We find that ratcheting up climate policy to a 2 ∘ compliant pathway results in welfare benefits through reduced air pollution that are larger than mitigation costs, even with avoided climate change damages neglected. The regional analysis demonstrates that the 2 ∘C pathway is therefore, from a social cost perspective, a "no-regret option" in the global aggregate, but in particular for China and India due to high air quality benefits, and also for developed regions due to net negative mitigation costs. Energy and resource exporting regions, on the other hand, face higher mitigation cost than benefits. Our analysis further shows that the result of higher health benefits than mitigation costs is robust across various air pollution control scenarios. However, although climate mitigation results in substantial air pollution emission reductions overall, we find significant remaining emissions in the transport and industry sectors even in a 2 ∘C world. We therefore call for further research in how to optimally exploit climate policy and air pollution control, deriving climate change mitigation pathways that maximize co-benefits. [ABSTRACT FROM AUTHOR]

Using case study analysis across three sectors in China (cement, electric vehicles and coal fired electricity generation) and theoretical insights from the innovation studies literature, this paper analyses the development of China's technological capabilities in low carbon technologies and the ways in which public policies have contributed to developing these capabilities. It finds that China has developed significant capabilities via a strategic approach. The paper's findings have significant implications for international policies designed to support low carbon technology transfer to developing countries and broader processes of low carbon technological change and development. Such policies should go beyond the traditional focus on the transfer of technology hardware to focus on the development of low carbon technological capabilities in developing country firms. [ABSTRACT FROM AUTHOR]

Farmers' perceptions of the local climate reflect their own judgments of climate change and may thus affect their adaptation behavior. However, the mechanisms between the provision of early warning information and farmers' perceptions and adaptation behavior are under-researched. To address this gap in the literature, this study uses original household survey data from nine provinces in China to examine the major factors influencing farmers' perceptions of drought and examines how perceptions affect adaptation behavior. The results show that over half of the sample farmers perceived that drought severity had increased during the past 10 years. Moreover, econometric analysis indicates that about 8% more farmers will adopt surface pipes in response to drought if early warning information about drought is provided. Farmers that perceived increasing drought severity are more likely to attempt to adapt by adopting water-saving technologies. The paper concludes by offering some policy implications for the presented results. [ABSTRACT FROM AUTHOR]

China is the largest wheat-producing country in the world. Wheat is one of the two major staple cereals consumed in the country and about 60% of Chinese population eats the grain daily. To safeguard the production of this important crop, about 85% of wheat areas in the country are under irrigation or high rainfall conditions. However, wheat production in the future will be challenged by the increasing occurrence and magnitude of adverse and extreme weather events. In this paper, we present an analysis that combines outputs from a wide range of General Circulation Models (GCMs) with observational data to produce more detailed projections of local climate suitable for assessing the impact of increasing heat stress events on wheat yield. We run the assessment at 36 representative sites in China using the crop growth model CSM-CropSim Wheat of DSSAT 4.5. The simulations based on historical data show that this model is suitable for quantifying yield damages caused by heat stress. In comparison with the observations of baseline 1996-2005, our simulations for the future indicate that by 2100 the projected increases in heat stress would lead to an ensemble-mean yield reduction of −7.1% (with a probability of 80%) and −17.5% (with a probability of 96%) for winter wheat and spring wheat, respectively, under the irrigated condition. Although such losses can be fully compensated by CO fertilization effect as parameterized in DSSAT 4.5, a great caution is needed in interpreting this fertilization effect because existing crop dynamic models are unable to incorporate the effect of CO acclimation (the growth-enhancing effect decreases over time) and other offsetting forces. [ABSTRACT FROM AUTHOR]

China has a large economic and demographic exposure to extreme events that is increasing rapidly due to its fast development, and climate change may further aggravate the situation. This paper investigates China's socioeconomic risk from extreme events under climate change over the next few decades with a focus on sub-national heterogeneity. The empirical relationships between socioeconomic damages and their determinants are identified using a hierarchical Bayesian approach, and are used to estimate future damages as well as associated uncertainty bounds given specified climate and development scenarios. Considering projected changes in exposure, we find that the southwest and central regions and Hainan Island of China are likely to have a larger percentage of population at risk, while most of the southwest and central regions could generally have higher economic losses. Finally, the analysis suggests that increasing income can significantly decrease the number of people affected by extremes. [ABSTRACT FROM AUTHOR]

This paper studies the interplay between climate, health, and the economy in a stylized world with eleven heterogeneous regions, with special emphasis on USA, Europe, China, India, and Africa. We introduce health impacts into a simple economic integrated assessment model where both the local cooling effect of S O and the global warming effect of C O are endogenous, and investigate how these factors affect the equilibrium path. Regions do not respond in the same way to climate change. In particular, emission abatement rates and health costs depend on the economic and geographical characteristics of each region. Two policy scenarios are considered, Nash and Optimal, for which we present both global and regional results. Results for Africa and China are highlighted. [ABSTRACT FROM AUTHOR]

Although previous studies show that urbanization contributes to less than 10 % of the long-term regional total warming trend of mean surface air temperature in northeast China (Li et al. ), the urban heat island (UHI) impact on extreme temperatures could be more significant. This paper examines the urbanization impact on extreme winter minimum temperatures from 33 stations in North China during the period of 1957-2010. We use the Generalized Extreme Value (GEV) distribution to analyze the distribution of extreme minimum temperatures and the long-term variations of the three distributional characteristics parameters. Results suggest that among the three distribution parameters, the position parameter is the most representative in terms of the long-term extreme minimum temperature change. A new classification method based on the intercommunity (factors analysis method) of the temperature change is developed to detect the urbanization effect on winter extreme minimum temperatures in different cities. During the period of rapid urbanization (after 1980), the magnitude of variations of the three distribution parameters for the urban station group is larger than that for the reference station group, indicating a higher chance of occurrence of warmer weather and a larger fluctuation of temperatures. Among different types of cities, the three parameters of extreme minimum temperature distribution of the urban station group are, without exception, higher than those of the reference station group. The urbanization of different types of cities all show a warming effect, with small-size cities have the most evident effects on extreme minimum temperatures. [ABSTRACT FROM AUTHOR]

This paper provides new evidence of regional warming trends from local Chinese observations covering the period 1951–2010. We used satellite-derived land data and weighted urban and rural temperature records (a weighted method) and estimate the regional warming trend, which involves natural climate change and human impact. The annual warming rate over the whole of China is 0.21 ± 0.02 °C/decade. The seasonal warming is 0.30 ± 0.05 °C/decade (Winter), 0.24 °C ± 0.03 °C/decade (Spring); 0.16 ± 0.02 °C/decade (Summer) and 0.21 ± 0.03 °C/decade (Autumn). The mean warming trend is lower than previous estimates (e.g. NMIC, CRU-China) using un-weighted methods (arithmetic average of all records). The warming difference between the weighted and un-weighted accounts for 27 % (12 %) of the NMIC (CRU-China) un-weighted estimate on the total warming. This indicates that previous estimations overestimated a regional warming trend. The differences can be partly attributed to the weighting of the urban effect which is taken into consideration in this study, resulting in a much slower temperature increase. Spatially, the northern part of China shows a larger difference than the south especially for winter and spring. We argue that it is of importance to take into consideration the influence of urban land-use change to improve the physical understanding of surface warming in China over past decades. [ABSTRACT FROM AUTHOR]

The transition from autocracy to democracy may lead a country to break-up. The break-ups of the USSR and Yugoslavia led to sharp falls in the level of emissions (while pre- and post-crisis trends are similar). If something like that would happen in China, an event with an unknown but small probability, projected emissions would fall by 50 % or more. The effect of a break-up on emissions in 2050 is larger than the difference between the SRES scenarios. [ABSTRACT FROM AUTHOR]

Shanghai is a low-lying city (3-4 m elevation) surrounded on three sides by the East China Sea, the Yangtze River Estuary, and Hangzhou Bay. With a history of rapid changes in sea level and land subsidence, Shanghai is often plagued by extreme typhoon storm surges. The interaction of sea level rise, land subsidence, and storm surges may lead to more complex, variable, and abrupt disasters. In this paper, we used MIKE 21 models to simulate the combined effect of this disaster chain in Shanghai. Projections indicate that the sea level will rise 86.6 mm, 185.6 mm, and 433.1 mm by 2030, 2050, and 2100, respectively. Anthropogenic subsidence is a serious problem. The maximum annual subsidence rate is 24.12 mm/year. By 2100, half of Shanghai is projected to be flooded, and 46 % of the seawalls and levees are projected to be overtopped. The risk of flooding is closely related to the impact of land subsidence on the height of existing seawalls and levees. Land subsidence increases the need for flood control measures in Shanghai. [ABSTRACT FROM AUTHOR]

China features the second largest irrigation area in the world. Several modeling studies on a global scale have shown the irrigation impact in China, but no direct observational evidence has been reported. In this paper, we evaluated the impact of irrigation on temperature in Jilin province, China, using meteorological and satellite observations. The results show that the temperature difference between highly and lightly irrigated sites is statistically significant and highly correlated to the effective irrigation area and crop sown area over the past 53 years. The magnitude of the difference in maximum air temperature was almost twice that of the difference in minimum air temperature. The linear regression coefficient of the time series difference in maximum air temperature was more than three times that of the minimum air temperature. Moreover, both meteorological and satellite observations show that the temperature difference is amplified during drier years. The difference in the magnitude of daytime land surface temperature (LST), between areas with irrigation percentages of more than 50 and less than 50, is as high as 2.7 K during the driest year. Overall, this study may provide evidence that an irrigation cooling effect exists in China. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the standardized anomalies of land surface temperature (LST) retrieved from the Special Sensor Microwave Imager (SSM/I) vertically polarized 37 GHz ( $T^v_{B,37~{\rm GHz}}$) brightness temperature over the Tibetan Plateau for the period 1987 to 2008. A radiative transfer model is used to derive LST from SSM/I $T^v_{Bv,37~{\rm GHz}}$, which is calibrated and validated using time series of field measured soil surface temperatures. Additional Plateau-scale verification is performed with monthly LST products from the Moderate Resolution Imaging Spectroradiometer, the Noah land surface model and air temperature measured by Chinese Meteorological Administration. Trend analysis shows that the annual and monthly standardized anomalies are increasing at an averaged rate of 0.5 decade. The highest positive trends are noted over the central part of the Plateau, which is on average 0.80 decade with a maximum of 1.44 decade. Conversely, a negative trend in the anomalies is found for the Taklamakan desert and the Himalayan foothills with a rate of −0.27 decade and reaching a maximum of −1.4 decade. In addition, we find that LST anomaly trends on the Plateau are seasonally dependent and increase with the elevation. These observed trends are in agreement with previous studies conducted with in-situ measurements, which demonstrates the use of long-term earth observation programmes for climate studies as has also been articulated in the 2007 IPCC report. [ABSTRACT FROM AUTHOR]

In the North China Plain, the grain yield of irrigated wheat-maize cropping system has been steadily increasing in the past decades under a significant warming climate. This paper combined regional and field data with modeling to analyze the changes in the climate in the last 40 years, and to investigate the influence of changes in crop varieties and management options to crop yield. In particular, we examined the impact of a planned adaptation strategy to climate change -'Double-Delay' technology, i.e., delay both the sowing time of wheat and the harvesting time of maize, on both wheat and maize yield. The results show that improved crop varieties and management options not only compensated some negative impact of reduced crop growth period on crop yield due to the increase in temperature, they have contributed significantly to crop yield increase. The increase in temperature before over-wintering stage enabled late sowing of winter wheat and late harvesting of maize, leading to overall 4-6% increase in total grain yield of the wheat-maize system. Increased use of farming machines and minimum tillage technology also shortened the time for field preparation from harvest time of summer maize to sowing time of winter wheat, which facilitated the later harvest of summer maize. [ABSTRACT FROM AUTHOR]

This paper uses pollen analysis to investigate and document the changing climate and vegetation during the Holocene based on a 400 cm core in depth obtained at a wetland site at Haligu (3,277 m a. s. l.) on the Jade Dragon Snow Mountain in Yunnan, China. By applying the Coexistence Approach to pollen data from this core, a quantitative reconstruction of climate over the last 9,300 years was made based on each pollen zone and individual core sample, which reveals the temperature and precipitation change frequently during that time. The qualitative analyses show that from 9300 to 8700 cal. yr BP, the vegetation was dominated by needle-leaved forest (mainly Pinus and Abies), indicating a slightly cool and moderately humid climate. Between 8700 and 7000 cal. yr BP, evergreen broad-leaved forest, dominated by Quercus, became the predominant vegetation type, replacing needle-leaved forest at this elevation, implying a warmer and more humid climate. During the period 7000 to 4000 cal. yr BP, the vegetation changed to mixed needle-leaved and evergreen broad-leaved forest, indicating a warm and moderately humid climate, but somewhat cooler than the preceding stage. From 4000 to 2400 cal. yr BP, the vegetation was again dominated by evergreen broad-leaved forest, but coniferous trees (mainly Pinus) began to increase, especially relative to a decline in Quercus. This implies that the climate remained warm and humid but slight drier than previously. The evergreen Quercus phase (8700-2400 yr BP) was designated as the Holocene climatic optimum in the Haligu core sediments. It is correlated with a markedly greater abundance and diversity of pteridophytes spores than was recorded before or after this period. From 2400 cal. yr BP to present, the vegetation was dominated by needle-leaved forest, of which Pinus formed the predominant component, accompanied by Abies and Tsuga. This reflects a slightly cooler, humid climate but also correlates with a period of increasing human settlement on the lower slopes of the mountain. At this elevated site, several hundred metres above the highest present day settlements, direct palynological evidence of anthropogenic activity is uncertain but we discuss ways in which the marked decline in Quercus pollen during this period may reflect the impact of ways in which natural resources of the mountain have been utilised. [ABSTRACT FROM AUTHOR]

Challenged by insufficient water resources and by degraded water quality caused by widespread pollution, China faces an imbalance between the supply and the demand of water for supporting the rapid social and economic development while protecting the natural environment and ecosystems. Climate change is expected to further stress freshwater resources and widen the gap between the demand for and supply of water. As a legacy of the earlier planned economy, water resources management has been primarily supply-driven, which largely fails to account for the economic nature of water resources in relation to their natural characteristics. This paper presents a historical perspective on the water resources management policies and practices in China, and recommends demand management and pollution control as key measures for improving water resources management to adapt to climate change based on the current political, socio-economic and water resources conditions. The past and future impacts of climate change on water resources in China and the general adaptation strategies are also presented. How demand management through increasing water use efficiency, improving water rights and rights trade, and effective regulation enforcement, along with pollution control could improve China's water resources management are discussed in details. Ultimately, China should develop a sustainable water resources management strategy based on both supply- and demand-side management options to make the limited water supplies meet the demands of economic development, social well-being and the conservation of ecosystems in the context of global climate change. [ABSTRACT FROM AUTHOR]

In this paper, change-points in time series of annual extremes in temperature and precipitation in the Zhujiang River Basin are analyzed with the CUSUM test. The data cover the period 1961-2007 for 192 meteorological stations. Annual indicators are analyzed: mean temperature, maximum temperature, warm days, total precipitation, 5-day maximum precipitation, and dry days. Significant change-points (1986/87, 1997/98, 1968/69, and 2003/04) are detected in the time series of most of the indicators. The change-point in 1986/87 is investigated in more detail. Most stations with this change-point in temperature indicators are located in the eastern and coastal areas of the basin. Stations with this change-point in dry days are located in the western area. The means and trends of the temperature indicators increase in the entire basin after 1986/87. The highest magnitudes can be found at the coast and delta. Decreasing (increasing) tendencies in total and 5-day maximum precipitation (dry days) are mostly observed in the western and central regions. The detected change-points can be explained by changes in the indices of the Western Pacific subtropical high and the East Asian summer monsoon as well as by change-points in wind directions. In years when the indices simultaneously increase and decrease (indices taking reverse directions to negative and positive) higher annual temperatures and lower annual precipitation occur in the Zhujiang River Basin. The high station density and data quality are very useful for spatially assessing change-points of climatic extreme events. The relation of the change points to large-scale oscillation can provide valuable data for planning adaptation measures against climate risks, e.g. for flood control, disaster preparedness, and water resource management. [ABSTRACT FROM AUTHOR]

The main portion of Tibetan Plateau has experienced statistically significant warming over the past 50 years, especially in cold seasons. This paper aims to identify and characterize the dynamics of inland lakes that located in the hinterland of Tibetan Plateau responding to climate change. We compared satellite imageries in late 1970s and early 1990s with recent to inventory and track changes in lakes after three decades of rising temperatures in the region. It showed warm and dry trend in climate with significant accelerated increasing annual mean temperature over the last 30 years, however, decreasing periodically annual precipitation and no obvious trend in potential evapotranspiration during the same period. Our analysis indicated widespread declines in inland lake's abundance and area in the whole origin of the Yellow River and southeastern origin of the Yangtze River. In contrast, the western and northern origin of the Yangtze River revealed completely reverse change. The regional lake surface area decreased by 11,499 ha or 1.72% from the late 1970s to the early 1990s, and increased by 6,866 ha or 1.04% from the early 1990s to 2004. Shrinking inland lakes may become a common feature in the discontinuous permafrost regions as a consequence of warming climate and thawing permafrost. Furthermore, obvious expanding were found in continuous permafrost regions due to climate warming and glacier retreating. The results may provide information for the scientific recognition of the responding events to the climate change recorded by the inland lakes. [ABSTRACT FROM AUTHOR]

urate simulation of soil organic carbon (SOC) dynamics is vitally important in researching the carbon cycle in terrestrial ecosystems. Especially, the application of SOC model at the regional scale has major implications for regional and global carbon cycling. This paper addresses the regional simulation for SOC in the surface layer (0~15 cm) of paddy soils in Wuxi and Changzhou, Jiangsu Province, China from 1982~2000 by linking a model of agro-ecosystem SOC dynamic simulation with GIS data on the basis of 100 × 100 m grids. The dataset includes soil profile descriptions and chemical data of 187 paddy soil samples in the Second National Soil Survey of China in 1982 and 352 paddy soil samples taken in 2000. Soil maps at a scale of 1:50,000 were used for the simulation. Results showed that the area of differences between simulated and observed SOC in 2000 (in the range of −3.6 to 3.6 Mg C ha) accounted for 50.6% of the total area. Also, when a 10% and 20% simulated increase, and a 10%, 20% and 30% simulated decrease in harvested crop straw and manure amendments were simulated to test the sensitivity of the model, simulated SOC would range from 10.26 to 50.40 Mg C ha with a standard deviation of 1.6 and 2.5, respectively. It is indicated that a key factor controlling SOC is the amount of residue and manure inputs. As for the assessment model suitability based on soil textures, soil types, and parent materials, the model seemed to perform better for clayey soils, groundwater-related paddy soils and soils derived from alluvial parent material than for loamy soils, surface water-related paddy soils and soil derived from loess material. [ABSTRACT FROM AUTHOR]

This paper explores changes in climatic variables, including solar radiation, rainfall, fraction of diffuse radiation (FDR) and temperature, during wheat season (October to May) and maize season (June to September) from 1961 to 2003 at four sites in the North China Plain (NCP), and then evaluates the effects of these changes on crop growth processes, productivity and water demand by using the Agricultural Production Systems Simulator. A significant decline in radiation and rainfall was detected during the 43 years, while both temperature and FDR exhibit an increasing trend in both wheat and maize seasons. The average trend of each climatic variable for each crop season from the four sites is that radiation decreased by 13.2 and 6.2 MJ m−2 a−1, precipitation decreased by 0.1 and 1.8 mm a−1, minimum temperature increased by 0.05 and 0.02°C a−1, maximum temperature increased by 0.03 and 0.01°C a−1, FDR increased by 0.21 and 0.38% a−1 during wheat and maize season, respectively. Simulated crop water demand and potential yield was significantly decreased because of the declining trend in solar radiation. On average, crop water demand was decreased by 2.3 mm a−1 for wheat and 1.8 mm a−1 for maize if changes in crop variety were not considered. Simulated potential crop yields under fully irrigated condition declined about 45.3 kg ha−1 a−1 for wheat and 51.4 kg ha−1 a−1 for maize at the northern sites, Beijing and Tianjin. They had no significant changes in the southern sites, Jinan and Zhengzhou. Irrigation, fertilization development and crop variety improvement are main factors to contribute to the increase in actual crop yield for the wheat–maize double cropping system, contrasted to the decline in the potential crop yield. Further research on how the improvement in crop varieties and management practices can counteract the impact of climatic change may provide insight into the future sustainability of wheat–maize double crop rotations in the NCP. [ABSTRACT FROM AUTHOR]

The pollen and spores of the Wuyun Formation (Danian, Early Paleocene) from Jiayin County, Heilongjiang Province, Northeast China, are studied in this paper. The Danian vegetation at Wuyun was composed of mixed temperate and subtropical broad-leaved forest, with an admixture of conifers. The climatic parameters, obtained by the Coexistence Approach based on the palynological and megafossil data, are Mean Annual Temperature of 14.8–16.8°C, Mean Annual Precipitation of 815.8–1,571.8 mm. Combining other climatic parameters in the Tertiary, we obtained the latitudinal temperature gradients: 0.24 in Paleocene, 0.1 in Eocene, 0.45 in Miocene and 0.55 in Pliocene, in the area of East Asia. All these values and modern latitudinal gradient of 0.7 suggest a climatic transition from Paleocene to today: the temperature at higher latitudes first increased then decreased gradually during last 65 Ma, while it changed slightly in lower latitudes. [ABSTRACT FROM AUTHOR]

With the implementation of the Chinese Natural Forest Conservation Program (NFCP) in 1998, over millions of hectares of forest in northeastern China have been protected through natural restoration (closure of hills). The impact of this program on the carbon budget of soil has not been evaluated until now. This paper presents results from a 6-year study of total CO2 efflux from both soil and litter ( Rtotal), CO2 flux from soil ( Rsoil), soil organic matter (SOM), soil microbe density, and litter input and root biomass at an uncut larch ( Larix gmelinii) forest and at a natural restoration site. The natural restoration area is a clear-cut site that was formerly part of a continuous portion of the uncut larch forest. Our objectives were to: (1) quantify the magnitude of CO2 efflux from typical sites in northeastern China; (2) explore the changes in thermal conditions, SOM, and annual CO2 flux during the 6-year natural restoration, and (3) evaluate the impact of NFCP on soil carbon processes. The annual Rsoil at the clear-cut site (58.6–68.2 mol m − 2 year − 1) was 113.6–228.4% (mean 141.5%) higher than that at the uncut larch site (29.6–58.4 mol m − 2 year − 1). At the same time, annual CO2 from litter at the clear-cut site (2.0–14.2 mol m − 2 year − 1) was only 23.5–84.5% (mean 52.5%) of that at the uncut larch site (5.4–16.8 mol m − 2 year − 1). SOM at the surface layer of the clear-cut site was 75% of that at the uncut larch site, but the soil microbial biomass (carbon) at the clear-cut site was much higher than that at the larch site ( p < 0.05). The percentage of bacteria, fungi and actinomycetes also were largely different between both sites. Natural restoration at the clear-cut site strongly affected thermal conditions. Although the soil temperature ( Tsoil) and effective accumulated $T_{\rm soil} > 0^{\circ}$C at the clear-cut site was much higher, the temperature sensitivity ( Q10) was much lower than that at the uncut larch site, and their differences decreased linearly from 2001 to 2006 ( p < 0.05). Moreover, Q10 at the clear-cut site significantly increased with the progress of natural restoration, which diminished the Q10 difference between the two sites (slope = − 0.2792, r2 = 0.4744, p < 0.05). These data imply that the NFCP natural restoration process has positively recovered the thermal condition of the clear-cut site to the level of uncut larch forest during the 6-year period. However, linear regression analysis showed that the 6-year natural restoration only slightly affected the annual soil CO2 efflux and SOM at both sites, and also did not diminish the differences between the two sites ( p > 0.10), indicating that a much longer time is necessary to restore the soil carbon in the clear-cut site. [ABSTRACT FROM AUTHOR]

This paper reviews the land cover changes on the Tibetan Plateau during the last 50 years partly caused by natural climate change and, more importantly, influenced by human activities. Recent warming trends on the plateau directly influence the permafrost and snow melting and will impact on the local ecosystem greatly. Human activities increased rapidly on the plateau during the last half century and have significant impacts on land use. Significant land cover changes on the Tibetan Plateau include permafrost and grassland degradation, urbanization, deforestation and desertification. These changes not only impact on local climate and environment, but also have important hydrological implications for the rivers which originate from the plateau. The most noticeable disasters include the flooding at the upper reaches of Yangtze River and droughts along the middle and lower reaches of Yellow River. Future possible land cover changes under future global climate warming are important but hard to assess due to the deficits of global climate model in this topographically complex area. Integrated investigation of climate and ecosystems, including human-beings, are highly recommended for future studies. [ABSTRACT FROM AUTHOR]

The Early–Middle Eocene palynoflora and paleoclimate of Changchang Basin, Hainan Island, South China, is described in the present paper and is compared with that of the Middle–Late Eocene, Hunchun City, Jilin Province, North China. The nearest living relatives (NLRs) of the recovered palynotaxa suggest a subtropical evergreen or deciduous broad-leaved forest at the center of the basin but a temperate evergreen or deciduous broad-leaved forest and needle-leaved forest growing in the peripheral part of the basin. Based on the climatic preferences of the NLRs, the climate in the Changchang Basin during the Early–Middle Eocene was warm and humid subtropical with a mean annual temperature of 14.2–19.8°C, a mean temperature of the warmest month of 22.5–29.1°C, a mean temperature of the coldest month of 1.7–11.9°C, a difference of temperature between coldest and warmest months of 12.1–24.6°C, a mean annual precipitation of 784.7–1,113.3 mm, a mean maximum monthly precipitation of 141.5–268.1 mm and a mean minimum monthly precipitation of 6.9–14.1 mm. A comparison of the palynoflora and paleoclimate between the Changchang Basin and Hunchun City, suggests essentially a similar climate in South and North China during Eocene time in contrast to the oceanic tropical climate in South China and cool dry temperate climate in North China as at present. [ABSTRACT FROM AUTHOR]

Northeast China comprises Heilongjiang, Jilin and Liaoning Provinces, with a total area of 790,000 km² and a population of about 107 million. Northeast China, located at relatively high latitudes, (from about 39 to 53°N), is one of the coolest regions in China with long and cold winters, a short growth season and frequent cold extreme events, which are adverse to agricultural production. However, since the 1980s, Northeast China has experienced significant warming with annual mean temperature rising by 1.0-2.5°C. The increase of accumulated temperature, the extension of the growth period and the recession of summer cool disasters all contributed to improved conditions for crop growth and led to a northward movement of the agricultural climate zone. In addition, the adaptation to warming including the adjustment of crop composition and structure as well as the adoption of advanced technologies greatly facilitated agricultural development. As a result, total grain production in the region increased rapidly. This paper describes in detail climate change, adaptation measures and final agricultural outcomes, alongside with economic and political factors and the role of different political actors in Northeast China. [ABSTRACT FROM AUTHOR]

Future global emissions of aerosols will play an important role in governing the nature and magnitude of future anthropogenic climate change. We present in this paper a number of future scenarios of emissions of black carbon (BC) and organic carbon (OC) by world region, which we combine with sulfate (SO4) assessed in terms of the emissions of its precursor, SO2. We find that aerosol emissions from the household and industrial sectors are likely to decline along almost all future pathways. Transportation emissions, however, are subject to complex interacting forces that can lead to either increases or decreases. Biomass burning declines in many scenarios, but the Amazon rainforests remain vulnerable if unsustainable economic growth persists. East Asia is the key region for primary aerosols, and trends in China will have a major bearing on the direction and magnitude of releases of BC (expected reductions in the range of 640--1290 Gg), OC (reductions of 520--1900 Gg), and SO2 (ranging from an increase of 21 Tg to a reduction of 30 Tg). Analysis of joint BC, OC, and SO2 emission changes identifies a number of key world regions and economic sectors that could be effectively targeted for aerosol reductions. [ABSTRACT FROM AUTHOR]

This paper assesses the impact of climate change on irrigated rice yield using B2 climate change scenario from the Regional Climate Model (RCM) and CERES-rice model during 2071-2090. Eight typical rice stations ranging in latitude, longitude, and elevation that are located in the main rice ecological zones of China are selected for impact assessment. First, Crop Estimation through Resource and Environment Synthesis (CERES)-rice model is validated using farm experiment data in selected stations. The simulated results represent satisfactorily the trend of flowering duration and yields. The deviation of simulation within ±10% of observed flowering duration and ±15% of observed yield. Second, the errors of the outputs of RCM due to the difference of topography between station point and grid point is corrected. The corrected output of the RCM used for simulating rice flowering duration and yield is more reliable than the not corrected. Without CO2 direct effect on crop, the results from the assessment explore that B2 climate change scenario would have a negative impact on rice yield at most rice stations and have little impacts at Fuzhou and Kunming. To find the change of inter-annual rice yield, a preliminary assessment is made based on comparative cumulative probability at low and high yield and the coefficient variable of yield between the B2 scenario and baseline. Without the CO2 direct effect on rice yield, the result indicates that frequency for low yield would increase and it reverses for high yield, and the variance for rice yield would increase. It is concluded that high frequency at low yield and high variances [ABSTRACT FROM AUTHOR]

The Eryuan palynoflora from the Late Pliocene of western Yunnan, China is described in this paper, and is compared with two contemporary palynofloras from Yangyi and Longling. The palynological data of the three locations are analyzed to reconstruct the climatic parameters of these areas at that time by using the Coexistence Approach. The Late Pliocene climatic parameters of Eryuan are estimated, i.e., the mean annual temperature ranged from 13.3 to 18.6°C, the mean temperature of the warmest month from 24.6 to 27.5°C, the mean temperature of the coldest month from 1.9 to 12.1°C, the difference in temperatures of coldest and warmest month from 14.2 to 16.6°C, the mean annual precipitation from 619.9 to 1484.3 mm, the mean maximum monthly precipitation from 143.8 to 245.6 mm, and the mean minimum monthly precipitation from 12.7 to 16.4 mm. Both paleovegetation and paleoclimate of the three localities are compared with the modern data at each location. The present study suggests a MAT decrease accompanied by a doubling of the MAP in the Longling area between the Late Pliocene and the present. This seems to be related to the uplift of Gaoligong Mountain in Longling which is now part of the eastern portion (Western Yunnan) of the Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Time series (1961-2000) of Penman-Monteith potential evapotranspiration estimates for 101 stations on the Tibetan Plateau and surrounding areas are analyzed in this paper. For the Tibetan Plateau as a whole potential evapotranspiration (PET) has decreased in all seasons. The average annual evapotranspiration rate decreased by 13.1 mm/decade or 2.0% of the annual total. Superimposed on this general decline are fluctuations ranging from app. 600 to 700 mm with above average rates in the 1970s and 1980s. On a regional basis, spatial trend distributions remain stable throughout the year with similar seasonal variations. Decreasing PET rates are more pronounced in winter and spring (80% of all stations) as compared to summer and autumn (58% of all stations). Maximum negative (positive) annual rates were recorded at two stations in the southern Qaidam Basin with -79.5 mm/decade (84.8 mm/decade) even though in general negative rates tend to be noticeably higher than positive rates. Changes in wind speed and to a lesser degree relative humidity were found to be the most important meteorological variables affecting PET trends on the Tibetan Plateau while changes in sunshine duration played an insignificant role. Stable daytime temperatures on the Tibetan Plateau have limited the importance of temperature trends for changes of PET rates. Negative evapotranspiration trends are therefore thought to be linked to a general decrease in intensity of the regional monsoon circulation rather than to reductions in sunshine duration. Reduced PET rates appear to be in contrast to a predicted increased hydrological cycle under global warming scenarios. [ABSTRACT FROM AUTHOR]

Estimates of forest vegetation carbon storage in China varied due to different methods used in the assessments. In this paper, we estimated the forest vegetation carbon storage from the Fourth Forest Inventory Data (FFID) in China using a modified volume-derived method. Results showed that total carbon storage and mean carbon density of forest vegetation in China were 3.8 Pg C (about 1.1% of the global vegetation carbon stock) and 41.32 Mg/ha, respectively. In addition, based on linear multiple regression equation and factor analysis method, we analyzed contributions of biotic and abiotic factors (including mean forest age, mean annual temperature, annual precipitation, and altitude) to forest carbon storage. Our results indicated that forest vegetation carbon storage was more sensitive to changes of mean annual temperature than other factors, suggesting that global warming would seriously affect the forest carbon storage. [ABSTRACT FROM AUTHOR]

Abstract With global concern on climate change impacts, developing countries are given special attention due their susceptibility. In this paper, change and variability in climate, land use and farmers' perception, adaptation and response to change are examined in Danangou watershed in the Chinese Loess Plateau. The first focus is to look at how climate data recorded at meteorological stations recently have evolved, and how farmers perceived these changes. Further, we want to see how the farmers respond and adapt to climate variability and what the resulting impact on land use is. Finally, other factors causing change in land use are considered. Local precipitation and temperature instrumental data and interview data from farmers were used. The instrumental data shows that the climate is getting warmer and drier, the latter despite large interannual variability. The trend is seen on the local and regional level. Farmers' perception of climatic variability corresponds well with the data record. During the last 20 years, the farmers have become less dependent on agriculture by adopting a more diversified livelihood. This adaptation makes them less vulnerable to climate variability. It was found that government policies and reforms had a stronger influence on land use than climate variability. Small-scale farmers should therefore be considered as adaptive to changing situations, planned and non-consciously planned. [ABSTRACT FROM AUTHOR]

This paper measures the economic impacts of climate change on China's agriculture based on the Ricardian model. By using county-level cross-sectional data on agricultural net revenue, climate, and other economic and geographical data for 1275 agriculture dominated counties, we find that under most climate change scenarios both higher temperature and more precipitation would have an overall positive impact on China's agriculture. However, the impacts vary seasonally and regionally. Autumn effect is the most positive, but spring effect is the most negative. Applying the model to five climate scenarios in the year 2050 shows that the East, the Central part, the South, the northern part of the Northeast, and the Plateau would benefit from climate change, but the Southwest, the Northwest and the southern part of the Northeast may be negatively affected. In the North, most scenarios show that they may benefit from climate change. In summary, all of China would benefit from climate change in most scenarios. [ABSTRACT FROM AUTHOR]

Can near-term public support of renewable energy technologies contain the increase of mitigation costs due to delays of implementing emission caps at the global level? To answer this question we design a set of first and second best scenarios to analyze the impact of early deployment of renewable energy technologies on welfare and emission timing to achieve atmospheric carbon stabilization by 2100. We use the global multiregional energy-economy-climate hybrid model REMIND-R as a tool for this analysis. An important design feature of the policy scenarios is the timing of climate policy. Immediate climate policy contains the mitigation costs at less than 1% even if the CO concentration target is 410 ppm by 2100. Delayed climate policy increases the costs significantly because the absence of a strong carbon price signal continues the carbon intensive growth path. The additional costs can be decreased by early technology policies supporting renewable energy technologies because emissions grow less, alternative energy technologies are increased in capacity and their costs are reduced through learning by doing. The effects of early technology policy are different in scenarios with immediate carbon pricing. In the case of delayed climate policy, the emission path can be brought closer to the first-best solution, whereas in the case of immediate climate policy additional technology policy would lead to deviations from the optimal emission path. Hence, technology policy in the delayed climate policy case reduces costs, but in the case of immediate climate policy they increase. However, the near-term emission reductions are smaller in the case of delayed climate policies. At the regional level the effects on mitigation costs are heterogeneously distributed. For the USA and Europe early technology policy has a positive welfare effect for immediate and delayed climate policies. In contrast, India looses in both cases. China loses in the case of immediate climate policy, but profits in the delayed case. Early support of renewable energy technologies devalues the stock of emission allowances, and this effect is considerable for delayed climate policies. In combination with the initial allocation rule of contraction and convergence a relatively well-endowed country like India loses and potential importers like the EU gain from early renewable deployment. [ABSTRACT FROM AUTHOR]

Moisture conditions, especially those that occur as multi-decadal anomalies, have profound impacts on society, especially in arid and semi-arid regions. However, the lack of high-resolution climate data for the first millennium CE greatly limits our understanding of how moisture variations have influenced history. Here, we present an 1882-year (134–2015 CE) tree-ring chronology developed from Qilian juniper (Juniperus przewalskii Kom.) growing in the western Qilian Mountains, northwest China. The tree-ring index correlates significantly with the May–June self-calibrating Palmer Drought Severity Index (sc-PDSI) and can be used to reconstruct May–June moisture variations since 241 CE. The reconstruction reflects moisture conditions at the annual to multi-decadal time scales over the past two millennia. During the period from the third to eighth centuries, there were prominent interdecadal fluctuations, with the third century and the late fifth century being the wettest and driest periods during the reconstruction, respectively. The transition from the wet third century to the dry fifth century corresponded with key events in Chinese history, namely the demise of the Western Jin Dynasty and the chaotic Southern and Northern Dynasties. Thus, our reconstruction provides new evidence for the potential linkage between abnormal climate conditions and social changes in ancient times. [ABSTRACT FROM AUTHOR]

Climate change has substantial impacts on regional hydrology in the major river basins. To figure out such latent hydrological impacts of changing climate, more reliable hydrological simulations are imperative. In this study, we evaluated the impacts of climate change on hydrological regime in the Upper Yangtze River Basin based on four downscaled and bias-corrected Global Climate Model outputs from Coupled Model Intercomparison Project Phase 5 under four Representative Concentration Pathways (RCP2.6, RCP4.5, RCP6.0, and RCP8.5) driving three hydrological models. Two model evaluation approaches were applied: simple and comprehensive. The comprehensive approach was used to evaluate models in the historical period, optimizing objective function at four gauges, and hydrological models were weighted for impact assessment based on their performance. In such a way, projected streamflow time series are obtained under different emission scenarios. Results show that the annual average discharge is projected to increase by 4.1–10.5% under the RCP scenarios at the end of twenty-first century relative to the reference period (1970–1999). Moreover, the high flow is projected to increase and the low flow to decrease indicating a higher probability of flood and drought occurrence in the basin. The severity of floods and droughts may increase. In comparison with the simple one-site model evaluation approach, the comprehensive method reveals that the anticipated extreme flow events would be less severe, and annual mean discharge slightly lower. The projected results imply that application of the comprehensive model evaluation approach could narrow the simulated spreads of projections significantly, and might provide more credible results. [ABSTRACT FROM AUTHOR]

Drought, which negatively affects crop yields, is expected to intensify in the future and will continue to threaten food security. Understanding crop yield responses to drought is essential for seeking more effective strategic adaptations and for reducing the risk of yield failure. However, how to regionally quantify drought-induced yield loss rates remains unclear. We addressed this gap through studying summer maize cultivated in the Huang-Huai-Hai farming region of China during 1981–2010. By incorporating yearly phenological data and dividing the growing season into the vegetative stage and reproductive stage, we used the standardized precipitation evapotranspiration index (SPEI) that is specific to different growth stages to reflect drought conditions. The spatial-temporal characteristics of drought conditions were further depicted, and the drought-induced yield loss rate was analyzed. The results showed that drought was unevenly and spatially distributed throughout the whole region, and extreme drought mostly occurred in the northern and northwestern regions even though they have a lower drought frequency. However, the drought tendency was alleviated across the maize growing season since the accumulated precipitation and average daily maximum temperature together determined the direction of drought severity. The drought-induced yield loss rate is related to both the intensification of extreme drought and the local precipitation conditions. These findings highlight the potential incentive of the drought-induced yield loss rate, and emphasize that innovation on farming activity is urgently needed to enhance maize productivity in regions with overexploited groundwater. [ABSTRACT FROM AUTHOR]

Four bias correction methods, i.e., gamma cumulative distribution function (GamCDF), quantile–quantile adjustment (QQadj), equidistant cumulative probability distribution function (CDF) matching (EDCDF), and transform CDF (CDF-t), to read are applied to five daily precipitation datasets over China produced by LMDZ4-regional that was nested into five global climate models (GCMs), BCC-CSM1-1m, CNRM-CM5, FGOALS-g2, IPSL-CM5A-MR, and MPI-ESM-MR, respectively. A unified mathematical framework can be used to define the four bias correction methods, which helps understanding their natures and essences for identifying the most reliable probability distributions of projected climate. CDF-t is shown to be the best bias correction method based on a comprehensive evaluation of different precipitation indices. Future precipitation projections corresponding to the global warming levels of 1.5 °C and 2 °C under RCP8.5 were obtained using the bias correction methods. The multi-method and multi-model ensemble characteristics allow to explore the spreading of projections, considered a surrogate of climate projection uncertainty, and to attribute such uncertainties to different sources. It was found that the spread among bias correction methods is smaller than that among dynamical downscaling simulations. The four bias correction methods, with CDF-t at the top, all reduce the spread among the downscaled results. Future projection using CDF-t is thus considered having higher credibility. [ABSTRACT FROM AUTHOR]

Coastal engineering is an important measure in coping with coastal risks. With global warming and sea level rising, the sustainable adaptation of the low-lying areas becomes urgent. An in-depth understanding of the relationship between coastal engineering and environmental changes can help improve the adaptation capability for climate change. Here, we use historical documents and synthesis approach to examine coastal engineering evolution on the Jiangsu coast, the largest lowland area along China's coastlines, and explore its response to local sea level and land use changes. The results show that coastal engineering here experienced a long-term period centered on sea-dike construction, with a shift from primary function of storm surge prevention since the eleventh century, towards a green coastal engineering approach in recent years. On the century scale, there was a close connection between local sea level change and coastal engineering change, while on the ten-year scale, population dynamics and land use changes were the key driving factors. Since the future climate and sea level change magnitude will be beyond what has been observed on the Jiangsu coast, it would be sensible to define a "critical time" that divides the near future and remote future. On such a basis, a strategic plan for the remote future may be formulated to prepare for the critical time when inevitable inundation occurs, and a second strategic plan may be adopted for the near future, to buy time for the coastal communities to make necessary preparations and at the same time to continue to use the resources. For the "near future," a green coastal engineering approach (in combination with the experiences gained from the Jiangsu coast) should be developed to provide a low cost, high efficiency technique for coastal defense schemes. The thoughts outlined above may be applicable also to a number of low-lying coastal regions of developing countries. [ABSTRACT FROM AUTHOR]

Landslides result in a significant number of casualties every year in China. The frequency and intensity of extreme precipitation are expected to increase due to climate change, leading to a change in landslide occurrence. This study focuses on climate change impacts on event rainfall characteristics that are commonly linked to landslide occurrence in China. A modelling framework was proposed to quantitatively assess the spatiotemporal change in event rainfall characteristics influencing landslide occurrences in China under future scenarios. First, an algorithm was used to extract the rainfall events from observed precipitation data and the 21 Global Circulation Models dataset. Then, the cumulative event rainfall-rainfall duration (E-D) threshold was identified and used as a proxy of landslide occurrence. Finally, the historical (1971–2000) and future (2031–2060 and 2066–2095) data of 21 GCMs were then applied to determine the E-D threshold in areas highly susceptible to landslides in China to assess the impact of climate change. Landslide occurrence is projected to increase potentially under all GCMs, by amounts ranging from 19.9% to 33.2% in the late 21st century compared to the historical period under the RCP4.5 and RCP85 scenarios, respectively. There are regional differences in the impact of climate change. Future landslide increases in the Northwest region and the Qinghai-Tibet region are the most significant, with consistency among multiple GCMs. However, there is only a slight increase in the South China region with high uncertainty. The monthly variations in landslides are bimodal, with the largest increases in spring and autumn. The results indicate that using a single GCM to assess climate change impacts may have biases, and consideration of median trends and variations among multiple GCMs is suggested. However, the study is a first hint on how climate change may affect landslide occurrence in the future, as the assessment of the effect of climate change on landslides is not straightforward based on only the precipitation-related proxy. The influence on air temperature and soil moisture and the selection of projection datasets and proxies should be carefully considered when applying the presented methods for climate change impacts on landslide studies. [ABSTRACT FROM AUTHOR]

There are clear signs that milk production growth is leveling off, and recently even declining, in China. Heat stress is one of the main reasons for the recent reduction in milk production. In this study, we computed the change in milk production as a result of heat stress in major milk production areas in China. We constructed a temperature–humidity index (THI) spatial layer to understand the monthly distribution of heat and moisture. We documented specific areas in northern China where cattle were at high risk to heat stress in specific months. THI values exceeded the threshold above which milk production declines during months of June, July, and August. Especially during July, the THI value was higher than the production threshold in recent years (2008 to 2016) and in projected future scenarios (2050 and 2070). THI-based milk yield losses were up from 0.7 to about 4 kg per cow per day in July 2016. These losses are projected to increase from 1.5 to 6.5 kg in 2050 and 2 to 7.2 kg in 2070 (representing production losses between 15 and 50%). These results suggest that climate change will have significant consequences for the dairy sector in major milk-producing areas in China. Our results are useful in identifying areas susceptible to heat stress where adaptive livestock management practices are needed to prevent significant production decreases. [ABSTRACT FROM AUTHOR]

Investigating oasis effects of different oasis-town configurations is key to understanding the ecological stability of the oasis. However, previous studies have not considered the impacts of oasis–town configurations on oasis effects. In this study, the Weather Research and Forecasting (WRF) model was used to conduct a series of 1-km-resolution simulations of the Hami Oasis, Xinjiang of China, to examine how different oasis–town configurations influenced the oasis effects. The actual landscape and four hypothetical landscapes were considered. Results indicated that the WRF model effectively reproduced the trends of the surface temperature, 2-m air temperature, 2-m relative humidity, and 10-m wind speed. It was also found that the effects of the town on the oasis were substantially greater when the former was located at the center of the oasis, rather than on the margin. At 850 hPa, the center of the temperature field was downstream from that of the wind field, whereas both coincided at lower levels. When the size of the town was doubled, the convergence center over the town weakened the strength of the divergent low-level winds from the oasis. This facilitated the infiltration of dry air from the surrounding desert into the oasis, which is detrimental to the healthy development of the oasis. Placing a town at the margin of the oasis is therefore advantageous to the development of the cold island, whereas a town at the center of the oasis is beneficial to the comfort of the residents. [ABSTRACT FROM AUTHOR]

A persistent concern about the social consequences of climate change is that large, vulnerable populations will be involuntarily displaced. Existing evidence suggests that changes in precipitation and temperature can increase migration in particular contexts, but the potential for this relationship to evolve over time alongside processes of adaptation and development has not been widely explored. To address this issue, we link longitudinal data from 20 thousand Chinese adults from 1989 to 2011 to external data on climate anomalies and use this linked dataset to explore how climatic effects on internal migration have changed over time while controlling for potential spatial and temporal confounders. We find that temperature anomalies initially displaced permanent migrants at the beginning of our study period, but that this effect had reversed by the end of the study period. A parallel analysis of income shares suggests that the explanation might lie in climate vulnerability shifting from agricultural to non-agricultural livelihood activities. Taken together with evidence from previous case studies, our results open the door to a potential future in which development and in situ adaptation allow climate-induced migration to decline over time, even as climate change unfolds. [ABSTRACT FROM AUTHOR]

Studies about climate change and the variation of the spatial pattern of war are extremely scarce in academia at present. Therefore, the temperature series and battle coordinates in imperial China from AD 5 to 1911 are integrated in this research, and their long-term quantitative relationship is examined by employing mathematical statistics such as one-way ANOVA, as well as the spatial analytical tool, standard deviational ellipse (SDE) in ArcGIS. Meanwhile, the temperature sequence is divided into three multicentennial warm–cold cycles, which are combined with different types of war (all war, agri-nomadic conflict, and rebellion) to reveal the spatial disparity of war under the influence of secular and periodic temperature change. Results show that (1) battle longitude and battle latitude are significantly different between warm and cold phases. (2) SDEs stretch toward the north/west/northwest in warm intervals but retreat south-/east-/southeastward in cold stages. (3) SDEs generally shift southeastward over time, and the variation of latitude is more evident than that of longitude, which corresponds to the overall cooling trend throughout the past 2000 years. Based on these research findings, we conclude that temperature fundamentally regulates the spatial difference of war in imperial China via controlling agricultural and pastoral productivity. This innovative study provides a robust climatological explanation of the historical conundrum why wars in ancient China distribute with specific directions, and it also lays a foundation for spatiotemporal investigations of climate change and human responses at long-term scales in the future. [ABSTRACT FROM AUTHOR]

Using household level and plot level survey data spanning over 10 years, this study examines the effects of climatic factors on the frequency of punctual on-demand deliveries of groundwater for irrigation at the farm level in the North China Plain. Data show that for the past few decades, farmers have experienced a decline in the frequency of punctual on-demand deliveries of groundwater for irrigation, which is measured by the proportion of the number of groundwater irrigations whose delivery timing matched the requests of farmers. Econometric estimation results show that both long-term climate conditions (mean temperature and total precipitation) and short-term weather conditions during the growing seasons have statistically significant effects on the frequency of punctual on-demand deliveries of groundwater for irrigation. However, these effects can show opposite results. The frequency of punctual on-demand deliveries of groundwater for irrigation is negatively associated with an increase in the long-term average temperature but is positively associated with a short-term temperature rise. The effects, moreover, may also differ in magnitude. Although the frequency of punctual on-demand deliveries of groundwater for irrigation is positively associated with higher precipitation levels in both the short-term and the long-term, the latter exerts a larger influence. [ABSTRACT FROM AUTHOR]

Using multiple proxy data of historical hydroclimate variations, this study first selects the five heaviest megadrought decades in North China during the last millennium and then depicts the spatial pattern of hydroclimate over the Northern Hemisphere through these five megadrought decades. The results shows that abnormally dry conditions existed in East Asia, North America, and Europe when megadroughts in North China during the last millennium. The intensity of dry conditions in North America was stronger than that in Europe. Then, through comparing the spatial patterns of hydroclimate from proxy data with ensemble modeling of nine CMIP5/PMIP3 models, we find that such megadroughts in North China, and the contemporaneously abnormal dry conditions over the Northern Hemisphere were very likely mainly induced by external forcing, i.e., large volcanic eruptions and weakened solar irradiation. These external forcing may lead to climate cooling and, hence, air motion downward at mid-lower layer of troposphere, inducing a much more stable troposphere; as well as, the land-ocean pressure differences were weakened, and, hence, there would be decreased water vapor flux from ocean to land. Both of intensified stability of troposphere and weakened vapor transportations to land would lead to precipitation decline and, as a result, would be favorable for drought. It is therefore necessary to consider these external forcing into future climate change predicting to improve our ability of predicting megadrought. [ABSTRACT FROM AUTHOR]

The Qinghai-Tibet Plateau constitutes unique mountain ecosystems that can be used for early detection of the impacts of climate change on ecosystem functions. We use the MAPSS-CENTURY 2 (MC2), a dynamic global vegetation model, to examine the potential responses of terrestrial ecosystems to climate change in the past (1961–2010) and future (2011–2080) under one medium-low warming scenario (RCP4.5) at a 1-km spatial resolution in the Upper Heihe River Basin (UHRB), northwestern China. Results showed that 21.4% of the watershed area has experienced changes in potential natural vegetation types in the past and that 42.6% of the land would undergo changes by the 2070s, characterized by a sharp increase in alpine tundra at the cost of cold barren land. Net primary productivity (NPP) and heterotrophic respiration (RH) have increased sharply since the mid-1980s and are projected to remain at reduced rates in the future. Overall, UHRB switched from carbon neutral to a carbon sink in 1961–2010, and the sink strength is projected to decline after 2040. Additionally, future climate change is projected to drive a decrease in water yield due to a slight decrease in precipitation and an increase in evapotranspiration (ET). Furthermore, we find large spatial variations in simulated ecosystem dynamics, including an upward trend of NPP, RH, and ET in the alpine zone, but a downward trend in the mid-elevation forest zone. These results underscore the complexity of potential impacts of climate change on mountain watersheds that represent the headwaters of inland river systems in an arid environment. [ABSTRACT FROM AUTHOR]

Climatic variation within a typical dry-valley area located in the southern Hengduan Mountains of China is studied, and the potential regional climate influences of large reservoirs in the area are discussed. Six meteorological stations near a reservoir are identified and classified into two categories (dry and non-dry valleys) to compare their level of climate change. Temperatures tended to increase since 1990 with a precipitation shift toward the dry season in both dry and non-dry valleys. Wavelet analysis shows that temperature and precipitation have significant variation with periods of 3.6 and 16.5 years, respectively. The standardized precipitation evapotranspiration index (SPEI) shows that dry valleys have multiple drought trends. Temperature in non-dry valleys changed more than that in dry valleys, but the variations of other indices in the two categories of valleys are not statistically different. The climatic variation of one station is in accordance with the reservoir filling, which is related to the orientation of the reservoir in the prevailing wind direction especially during summer. This study provides a profile of the climate change of dry valleys and documents the influence of large artificial reservoirs on regional climate. [ABSTRACT FROM AUTHOR]

To stop global warming at well below 2° C, the bulk of the world’s fossil fuel reserves will have to be left in the ground. Coal is the fossil fuel with the greatest proportion that cannot be used, and various advocacy groups are campaigning for a ban on the opening of new coal mines. Recently, both China and the USA implemented temporary moratoria on the approval of new coal mining leases. This article examines whether these coal mining bans reflect the emergence of a global norm to keep coal under the ground. To that end, we review recent coal mining policies in the four largest coal producers and explain them comparatively with a framework based on interests, ideas and institutions. We find that the norm of keeping coal in the ground remains essentially contested. Even in those countries that have introduced some form of a coal mining moratorium, the ban can easily be, or has already been, reversed. To the extent that the norm of keeping coal in the ground has momentum, it is primarily due to non-climate reasons: the Chinese moratorium was mostly an instance of industrial policy (aiming to protect Chinese coal companies and their workers from the overcapacity and low prices that are hitting the industry), while the USA’s lease restrictions were mainly motivated by concerns over fiscal justice. We do not find evidence of norm internalisation, which means that the emerging norm fails to gain much traction amid relevant national actors and other (large) coal producing states. If proponents of a moratorium succeed in framing the issue in non-climate terms, they should have a greater chance of building domestic political coalitions in favour of the norm. [ABSTRACT FROM AUTHOR]

Previous studies suggest that the Pacific Decadal Oscillation (PDO) modulates annual and summer precipitation patterns over East China. In this study, the effect of the PDO on monthly precipitation anomalies over this region is investigated. The new results show that the effect is month-dependent. The well-known North-South dipole patterns of annual precipitation are dominated by the July-August precipitation. In other months, the corresponding patterns vary in strength, position, and even shape. For example, the May and June precipitation patterns show opposite signs to the July-August or annual mean patterns, whereas the September-December monthly precipitation anomalies show a triple pattern. Monthly precipitation patterns over East China are largely determined by large-scale moisture transport controlled by atmospheric circulation. The PDO affects East China precipitation patterns by modulating the large-scale circulation pattern. [ABSTRACT FROM AUTHOR]