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With the intensification of global warming and anthropogenic activities, warming or drying episodes with respect to water deficit has brought severe challenges across the globe. It becomes imperative to understand the drought characteristics as well as water resource availability in such regions. In this paper, we employ trend analysis to investigate the tendency of Potential Evapotranspiration (PET) and Climatic Water Balance (CWB) from 1979 to 2017 in the Jhelum river basin. We applied Thornthwaite parameterization which is based on latitude and monthly mean temperature for the computation of PET. The results showed that annual PET of Srinagar and Quazigund stations has increasing tendency while annual CWB has decreasing tendency for all the selected stations in the basin. The trend test applied to monthly PET and CWB indicate that monthly PET has increasing tendency in most of the months while monthly CWB has decreasing tendency in most of the months for all the selected stations in the basin. In addition to this, the drought events were characterized using Standardized Precipitation Evaporation Index (SPEI) based on 3, 6 and 12-month time scales. The SPEI was also applied to investigate the spatio-temporal characteristics of drought during the study period in the basin. The spatial patterns of drought severity were derived based on the Average Recurrence Interval (ARI). The temporal analysis revealed that an average of 65 long term, 69 intermediate term and 74 short term drought events were observed across the basin. However the spatial characteristics indicated that drought becomes more severe with long return periods in the western part of the basin. This study also investigated the influence of large scale climatic variables on 3 month SPEI over the basin using cross wavelet analysis. The results show that the drought characteristics are significantly influenced by both the ENSO and ENSO-M events throughout the Jhelum basin.

This paper presents results of a high-resolution study of bottom sediments from the central and northern parts of the Chukchi Sea. Magnetic susceptibility and grain size distribution within the sediments indicate calm depositional conditions of mainly lithogenic material. The biogenic material is dominated by SiO2bio (up to 15%) and to a much lesser extent by Corg (up to 2%) and Ntot (up to 0.25%). The distinct increase of organic material within the uppermost parts of the cores causes a decrease of magnetic susceptibilty and reflects an increase of biological productivity of the Chukchi Sea, triggered by global warming of the climate. Fallout activity peaks of 137Cs, measured in the core taken in the central area of the Chukchi Sea, are assumed to represent the fall-out of the accidents of the Chernobyl nuclear power plant in 1986 and of the Fukushima nuclear power plant in 2011. The two fallout peaks of 137Cs in the sediments of the northern area correspond to the maximum of the atmospheric tests of nuclear weapons in 1963 and to the accident at Chernobyl nuclear power plant in 1986. Rates of recent sedimentation, dated by 137Cs fall-out peaks and by additional measurements of 210Pb are estimated to be 2–2.7 mm a−1 in the central part and 0.9–1.3 mm a−1 in the northern part of the Chukchi Sea.

Based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) simulations, this paper evaluated the performance of the state-of-the-art climate models in simulating the interannual variability of the western North Pacific subtropical high (WNPSH), East Asian jet (EAJ) and East Asian summer rainfall (EASR), and further projected their potential changes in a future warmer world. The results show that the multimodel ensemble mean (MME) simulation has good ability to model the interannual variability of the WNPSH, EAJ and EASR, although some discrepancy exists among the individual models. The MME simulation can also reasonably capture the observed relationship of the EASR with the WNPSH and the EAJ. Under the RCP4.5 and the RCP8.5 scenarios, the interannual variability in WNPSH, EAJ and EASR is projected by the MME to increase in the 21st century. In addition, the WNPSH and EAJ would still be the dominant systems influencing the East Asian summer precipitation under global warming scenarios. But the linkage of the EASR to the WNPSH may be slightly weaker and that to the EAJ may be slightly stronger in the 21st century as compared to the present.

This paper presents vegetation and climate reconstructions for the forest zone in the central part of the East European Plain, Russia, for the time period 10,000–7900 cal. BP. Reconstructions were based on pollen records from three key regions located in taiga, mixed coniferous-broadleaved and broadleaved forest zones. Results showed that the considered period was characterized by relatively low air temperatures and high precipitation compared with modern conditions. Analysis of the long-term pattern of the mean annual temperature for all three regions reveal two synchronous significant cooling periods observed 9300–9100 cal. BP and 8500–8100 cal. BP as well as rapid growth of the air temperature in 8100–7800 cal. BP, when the annual temperatures increased by 3 °C during about 300 years. The cooling phase of 8500–8100 cal. BP could correspond to the distinct “8.2 ka event” widely recorded across Europe. Periods of climate warming are coincided with periods of precipitation rise whereas the cool phases are characterized by its decrease. The ratio of actual evapotranspiration and precipitation amount selected as indicator of surface moistening conditions decreased significantly in period of cooling phases (down to 0.27) and can be used as a clear indicator of ground surface overwatering and strengthening of mire formation processes.

Based on the data of five observed meteorological elements (temperature, precipitation, wind speed, sunshine duration, and relative humidity) from 22 stations, the paper investigated the climate variations in northern Xinjiang over the past 50 years. The analytical results showed that both the temperature and the precipitation have increased significantly (0.35 °C/10 y, 11.2 mm/10 y) during the period of 1960–2011. An abrupt change was detected to have occurred in 1986 for temperature and in 1987 for precipitation. Autumn was the season when the temperature increased most dramatically, and winter and autumn were the seasons when the precipitation increased most dramatically. The twenty years after 1990 were the warmest and wettest two decades of the past ∼50 years, but the warming and wetting paces have slowed down during the same period. The results also showed that the mean annual minimum temperature increased more dramatically than the mean annual maximum temperature, resulting in a greatly reduced diurnal range. The reasons or mechanisms for rising trend of temperature during the past 50 years and also for the faster rising rate of the temperature in northern Xinjiang and the adjacent areas have been reasonably explored in published literature. However, the reasons or mechanisms for the rising trend of the past 50-year precipitation in northern Xinjiang and the adjacent areas have not been reasonably explored. This wetting trend has not extended further to the surrounding areas including Republic of Mongolia, major part of North China, and five republics of the former Soviet Union, and the need is thus pressing to explore the reasons or mechanisms behind this relatively “localized” wetting trend.

Based on the long-term trends analysis of five meteorological parameters (temperature, precipitation, wind speed, sunshine duration and relative humidity) in the four chosen stations of different settings, this paper attempts to reveal the characteristics of climate change in Urumqi City during 1960–2013. Our analytical results showed that both the temperature and precipitation in the Urumqi City have increased significantly since the middle 1980s. Autumn was the season when the temperature increased most drastically, and winter was the season when the precipitation increased most drastically. The average minimum temperature increased faster than the average maximum temperature, thus resulting in greatly reduced diurnal and annual temperature ranges. The wind speed was weakening significantly since the middle 1980s. The sunshine duration did not display any geographic coherence or consistency among different stations. The relative humidity has maintained more or less a constant, meaning that the absolute amount of water vapor has been increased under warming conditions. Comparatively, the Urumqi station (i.e., the urbanized area) had the most pronounced changes in temperature, precipitation and sunshine duration and the most pronounced changes were possibly due to the combined effects of natural and anthropogenic factors. Climate change in the mountainous area was synchronous with that in the plain area and the underlying surfaces and topographies, together with degrees of human activities, distinguished the regional climatic responses to global warming.

The impact of climate change on agricultural production is integral to understanding the impacts of historical climate change on society and the economy, which could provide historical references for dealing with current and future global climate change. Continuous proxy series of human activity that extend to more than 1000 years in the past are few, especially for high-resolution series. There was a lack of quantitative records of grain harvest in Chinese history except during the Qing Dynasty. Thus, it is difficult to reconstruct long-term and high-resolution agricultural production series. In this paper, the method developed by Su et al. (2014) is used to reconstruct the grain grade sequence with a 10-year resolution from 210 BC to 1910 AD in China, and the changes between temperature and grain yield grades are compared. A positive correlation between the winter half-year temperature departure and the grain yield from 210 BC to 1910 AD in China was found. The change of grain yield grades could be divided into five stages. The bumper harvest stages corresponded to the warm periods, and poor harvest stages corresponded to the cold periods. In both warm and cold periods, the grain yield grades assumed a trend of convergence with the temperature increase. The sensitivity of grain yield to temperature change became weakened over time from 210 BC to 1910 AD, perhaps due to the strengthened adaptive capacity of agriculture to temperature change, with the extension of farming to southern China, progress of farming technology, and introduction of high-yielding crop varieties. Remote linkages between the agricultural change in China and the human civilization in Europe were found, implying the impacts of temperature change are globally synchronous.

In a recent paper (Chen et al., 2013), fractional changes in temperature were correlated with fractional changes in anthropogenic emissions of carbon dioxide in order to estimate the amount of warming attributable to CO2 emissions. No justification was given for using the emissions rate rather than cumulative changes in atmospheric CO2 and the assumptions are not physically-based. This leads to counter-physical predictions, such as cases where increased heating causes the Earth to cool. Furthermore, a 10-year shift in start date alters the calculated elasticity by a factor of 2. A standard energy balance model is physically-based and outperforms the Chen et al. (2013) model, and its fitted transient climate response is consistent with changes in atmospheric CO2 causing warming equivalent to approximately 100% of the temperature change observed since 1960, consistent with formal attribution analyses. It is cautioned that purely statistical correlations are not able to demonstrate cause, and that they are particularly poor at attribution when there is no physical basis for the selection of variables and functional forms used in the correlation analysis.

Temperature variations under climate change have greatly affected regional hydrological processes and agricultural production in the Lancang River Basin, southwestern China. This paper analyzes the spatiotemporal temperature variations in this region from 1960 through 2009 using multiple methods with observed temperature series data from 11 meteorological stations. These methods consist of the rotated empirical orthogonal function analysis (REOF), the Mann–Kendall method, the inverse distance weighting interpolation and the linear regression. The results are as follows: (1) A latitudinal temperature gradient of 4 C°/degree existed in this region, and a longitudinal temperature gradient of 1.5 C°/degree was present in both northern and southern areas; the lowest average temperature was observed in the northern part of the basin. (2) Based on spatial patterns from the REOF analysis and regional features including topography, monsoons and climate, four subzones with different temperature variability were designated, and all exhibited significant upward trends in temperature during the studied period. (3) The year 1990 was found to be the abrupt point of the regional temperature variations. The abrupt points in spring and autumn (mainly after 1990) were found several years later than those in summer and winter (mainly before 1990). This research is not only helpful in improving our understanding of the temperature response to global warming in the Lancang River Basin, but also provides a basis for basin management.

Studies of vegetation successions related to climate changes during previous interglacial periods provide important insights into the mechanisms of climate change during the current interglacial and enable predictions of future climate impacts on ecosystems. The Chinese Loess Plateau (CLP), which is particularly sensitive to climate warming, presents an excellent site for such studies. However, few detailed records exist of vegetation and climate variations during interglacial periods on the CLP. This study obtained a series high resolution pollen records from the Luochuan loess-paleosol section on the CLP, and the paper discusses the vegetation and climate histories during three previous interglacial periods (MIS 9, MIS 7 and MIS 5). The Artemisia-Chenopodiaceae steppe vegetation that covered this area between 342 ka and 312 ka changed to Humulus-Chenopodiaceae steppe between 312 ka and 302 ka, and then reverted to Artemisia-Chenopodiaceae steppe after 302 ka. From 250 ka to 237 ka, the vegetation type remained Artemisia-Chenopodiaceae steppe, and then changed to Artemisia-Humulus steppe between 237 ka and 227 ka. Between 227 ka and 195 ka, the vegetation returned to Artemisia-Chenopodiaceae steppe. During MIS 5, vegetation of the study area changed from Pinus-Rosaceae-Chenopodiaceae forest-steppe between 129 ka and 117 ka, to Artemisia-Humulus-Ranunculaceae steppe from 117 ka to 96 ka. After 96 ka, the vegetation types changed to Pinus-Betula-Chenopodiaceae forest-steppe. Comparing these pollen records with other climatic proxies from the CLP and the oxygen isotope records from the Pacific Ocean suggests that vegetation and climate change features around the study site were synchronous with East Asian monsoon variations near 65°N. The regional tectonic uplift probably provided only a subordinate influence on vegetation and climate variation on the CLP during MIS 5.

In terrestrial records from Central and Eastern Europe the end of the Last Interglacial seems to be characterized by evident climatic and environmental instabilities recorded by geochemical and vegetation indicators. The transition (MIS 5e/5d) from the Last Interglacial (Eemian, Mikulino) to the Early Last Glacial (Early Weichselian, Early Valdai) is marked by at least two warming events as observed in geochemical data on the lake sediment profiles of Central (Grobern, Neumark–Nord, Klinge) and of Eastern Europe (Ples). Results of palynological studies of all these sequences indicate simultaneously a strong increase of environmental oscillations during the very end of the Last Interglacial and the beginning of the Last Glaciation. This paper discusses possible correlations of these events between regions in Central and Eastern Europe. The pronounced climate and environment instability during the interglacial/glacial transition could be consistent with the assumption that it is about a natural phenomenon, characteristic for transitional stages. Taking into consideration that currently observed “human-induced” global warming coincides with the natural trend to cooling, the study of such transitional stages is important for understanding the underlying processes of the climate changes.