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This paper seeks to measure farmers' perceptions on climate variations, and examine the effects of such variations on cassava production in Ghana. Using a three-stage sampling technique involving cluster, stratified, and simple random sampling techniques, structured questionnaires were administered to 252 smallholder cassava farmers in the Awutu Senya District of the Central Region, Ghana. This was supplemented with focus group discussion sessions with male and female cassava farmers for the purpose of triangulating the quantitative and qualitative data. The study showed an overwhelming 98% of respondents, comprising 57% males, and 43% females, acknowledging to have noticed changes in the weather patterns over the last 30 years. While 85% of respondents said rainfall was decreasing, 75% said the rains did not come at the expected time, with 58% of them saying reduced rainy periods were the noticeable changes. Respondents attributed the changes in weather patterns to environmental degradation (72%), natural phenomenon (15%), and punishment by God (1%). Majority of them (97%) said they had suffered from decreasing yields in cassava as a result of seasonal variations in temperature and rainfall. The paper makes a strong case for activities that will bridge the knowledge-and-skill gap between male and female farmers. [ABSTRACT FROM AUTHOR]

In contemporary times, climate variability has spurred interdisciplinary efforts to gauge the impacts of climate change. Drawing from field-based research in Arunachal Pradesh, India, this paper explores what constitutes 'climate knowledge' when bio-physical environmental changes are perceived differently among community members. To associate bio-physical realities with socio-cultural knowledge and practice, it is necessary to shift the frame of reference. This enables an interdisciplinary study of climate change that is more productive for both natural sciences and interpretative social sciences. We also discuss the hybrid nature of climate's ontological and material relations emerging from colonialism, capitalism, and development, which further shape the relationship between community and environment. Finally, the article discusses the loss of Indigenous communities' cosmological world-making practices in the context of weakening traditional livelihood practices and social cohesion. The paper suggests that climate change needs to be considered not only as a loss of biodiversity but also as a loss of culture when it comes to interpreting the environment. [ABSTRACT FROM AUTHOR]

Pasturelands are globally extensive, sensitive to climate, and support livestock production systems that provide an essential source of food in many parts of the world. In this paper, we integrate information from remote sensing, global climate, and land use databases to improve understanding of the resilience and resistance of this ecologically vulnerable and societally critical land use. To characterize the effect of climate on pastureland productivity at global scale, we analyze the relationship between satellite‐derived enhanced vegetation index data from MODIS and gridded precipitation data from CHIRPS at 3‐ and 6‐month time lags. To account for the effects of different production systems, we stratify our analysis by agroecological zones and by rangeland versus mixed crop‐livestock systems. Results show that 14.5% of global pasturelands experienced statistically significant greening or browning trends over the 15‐year study period, with the majority of these locations showing greening. In arid ecosystems, precipitation and lagged vegetation index anomalies explain up to 69% of variation in vegetation productivity in both crop‐livestock and rangeland‐based production systems. Livestock production systems in Australia are least resistant to contemporaneous and short‐term precipitation anomalies, while arid livestock production systems in Latin America are least resilient to short‐term vegetation greenness anomalies. Because many arid regions of the world are projected to experience decreased total precipitation and increased precipitation variability in the coming decades, improved understanding regarding the sensitivity of pasturelands to the joint effects of climate change and livestock production systems is required to support sustainable land management in global pasturelands. Plain Language Summary: Pastures, which provide food for livestock, are the most extensive land use on the planet, and their productivity depends on the timing and amount of rainfall they receive. In this paper, we use data on vegetation productivity, rainfall, and land use in order to determine the ability of pastures to remain unaffected by a disturbance and the time required for pastures to recover following a disturbance. To determine the effects of rainfall on pastures, we analyze the relationship between productivity and rainfall at 3‐ and 6‐month time intervals. We also take into account pasture management and whether pastures are located in dry or humid areas of the world. In dry regions, rain from the current season, rain from the last two seasons, and vegetation productivity from the previous growing season explain nearly 70% of current season vegetation productivity. Pastures in Australia are least capable of withstanding rainfall deficits, while pastures in Latin America recover more slowly after drought compared to other regions. Dry regions of the world are predicted to receive less rain less regularly in the coming decades, so improved understanding of the sensitivity of pastures to expected changes in rainfall will help support sustainable management of global pastures. Key Points: In Australia, pasturelands have both low resistance and low resilience relative to other regions across the worldSouthern South America has the lowest resilience globally, which is indicative of slow vegetation recovery after a disturbanceA total of 14.5% of global pasturelands experienced greening or browning trends, with the majority of these locations showing greening [ABSTRACT FROM AUTHOR]

Societies adapt to climate variations and develop unique cultures that lead to distinctive economic behaviour across different regions. To estimate the climate-economic link and test the hypothetical role of culture, this paper uses a nationwide survey at the household level in China, together with historical temperature data at the prefectural city level for empirical analysis. The results show the significant role of local climate variations on consumption, savings and investment decisions by households. Harsh weather conditions are associated with lower consumption, lower income and higher savings. Such climate characteristics are also associated with a lower probability of purchasing risky financial assets. Using a sample of migrating families, we find strong evidence that culture is an important channel in the climate-economic relationship. Additional support for this view is found through the “catching up with the Joneses” effect documented in the economics literature. Overall, this research provides an alternative perspective for understanding the long-term behavioural impact of climate change. [ABSTRACT FROM AUTHOR]

The total zenith tropospheric delay (ZTD) and its components, hydrostatic and wet parts are important parameters of the atmosphere and directly or indirectly reflect climate processes. This possibility can be more adaptive when meteorological data are combined to co-located meteorological sensors with GPS stations. In this paper eighteen months with one hour time interval ZTD estimates of a permanent GPS station are analyzed with the associated atmospheric parameters provided from a co-located meteorological sensor. The mathematical relationship through the multiple stepwise regression analysis reflects the plausible physical link of temperature and relative humidity values with ZTD's. This regression equation is assessed by a second data set performed by a small GPS baseline few months later for the same study area. It was found that mainly due to the zenith wet delay variations and with the help of fundamental meteorological equations the behavior of water vapor pressure can be monitored and estimated. This is possible when an appropriate setup of GPS stations and a co-located meteorological sensor exist and if the GPS stations sound the same part of atmosphere. Therefore, the GPS tropospheric products are good indicators for a climate monitoring tool and can help address the physics of a climate model. [ABSTRACT FROM AUTHOR]

The changing environment enhances the hydrological cycle and increases the frequency of extreme floods. In this paper, the impacts of climate variability on flood season segmentation are determined and the scientific basis for determining corresponding flood limiting water levels (FLWLs) is provided. Climate variation was determined and then the flood season was divided into several sub-seasons using the results of the set pair analysis method (SPAM) and four indices; peak floods crossing the transitional periods were sampled to obtain a design flood hydrograph; and, finally, seasonal FLWLs were determined for reservoir operation. The performance of this reservoir staging operation was evaluated for a case study in the Chengbihe Reservoir, China. [ABSTRACT FROM AUTHOR]

According to Food and Agriculture Organization and Intergovernmental Panel on Climate Change reports, climate change will lead to a severe food-supply problem. In the future, food production will continually decrease because of aggravated effects of climate change, causing food production to continually decrease. Food production will be unable to satisfy the demand of the global population, leading to a food-security crisis. As the world population continues to increase, the shortage of food will become increasingly severe, particularly for those located in “climate impact hotspots” of tropical, subtropical, small-island countries, and countries that are dependent on imports to meet domestic demand such as Taiwan. Numerous Taiwanese studies have suggested that agricultural and fishery productivity has declined because of climate variation, which may cause changes and instability in food quantity and quality, and increase deficiency and uncertainty in the food supply. Therefore, to discuss the risks posed by climate change to the stability of food supply and demand, this paper, taking Taiwan as a case, explored the impact of climate variation on food security and future adaptation strategies. TaiCCAT’s supportive system for decision-making (TSSDA) was adopted here to assess and analyze the current situations of agricultural and fisheries production and supply, as well as future food supply risks, in addition to evaluating the deficiencies in the existing climate adaptation strategies in order to plan and revise feasible future adaptation alternatives. Based on the rule of risk management, the adaptation strategies recommended in this study were differentiated into two categories: proactive adaptation and planned adaptation. Proactive adaptation is emphasized to counter the uncertainty of food production, which increases the difficulty of production and necessity to import food. Conversely, planned adaptation can be used to manage the uncertainty of food supply to implement adjustments in production and marketing, as well as to mitigate the impact of climate variation. [ABSTRACT FROM AUTHOR]

This study analyzed the temporal variation of Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) of Hun River upstream forest in northeastern China and its correlation with climate parameters (temperature and precipitation) during the period of 2000-2009. We examined the interannual variation of forest, seasonal variation of forest and lag effects of climate variables (temperature and precipitation) on forest using simple regression and correlation. The objective of this paper was to compare the results of our research and previous researches and to show that the conclusions derived from broad-scale researches provided a direction of policy, but the local details were essential to local management. We found that the annual mean NDVI was significantly correlated with annual mean temperature. The forests studied in our research showed insignificant increase trends except for Fraxinus spp. forest. We concluded that the temperature was the limiting factor of vegetation growth in our study area and the forest which was in the core geographic area of its distribution was resilient to climate variation. When seasonal variation was examined, we found the largest increase trend of seasonal mean NDVI was in winter. The result was different from the outcome of previous research at national scale. There were 3 months lag effects of climate variables on vegetation of our study area in summer and autumn, which was consistent with researches at broad scales. The reasons of both difference and indifference were discussed in this paper. We also got information about tree species for local management using MODIS NDVI. The results of this work suggested that information from local scales would be important complements to researches at broad scales and were essential for local managers. [ABSTRACT FROM AUTHOR]

The formation of tree-rings is closely related to climate variation. This paper establishes the tree-ring chronology of Pinus massoniana for a period of 36 years and examines the relationship between the tree-ring chronology and climatic conditions based on tree-ring width samples from three sites on the northeast slopes of Yangming Mountain. This data is used to study the relationship between the tree-ring width of a young tree and climatic conditions in a moist hilly region of southern China and to understand the general pattern of climate variation and its effects on tree growth in the past in this region. The results indicate that changes in tree-ring widths in these sites are closely related to local climatic conditions. There is a significant positive correlation between the radial growth of Pinus massoniana and the mean temperature of the current year from January to May (coefficient of correlation, R, is 0.596, P<0.01) and the mean temperature of the previous year from June to July (R is 0.639, P<0.01). The radial growth of Pinus massoniana is negatively correlated with the total precipitation of the previous year from January to March and November to December (R is -0.46, P<0.05) and negatively correlated with the total precipitation of the previous year from June to July (R is -0.582, P<0.05). The effect of precipitation on the radial growth of Pinus massoniana is known as the 'hysteresis effect'. [ABSTRACT FROM AUTHOR]

Droughts have become more severe and frequent due to global warming. In this context, it is widely accepted that for drought assessments, both water supply (rainfall) and demand (standardized precipitation evapotranspiration index, SPEI) should be considered. Using SPEI, we explored the spatial-temporal patterns of dry and wet annual and seasonal changes in five sub-regions of East Asia during 1902–2018. These factors are linked to excess drought frequency and severity on the regional scale, and their effect on vegetation remains an important topic for climate change studies. Our results show that the SPEI significantly improved extreme drought and mostly affected the SPEI-06 and SPEI-12 growing seasons in East Asia during 1981–2018. The dry and wet annual SPEI trends mostly affect the five sub-regions of East Asia. The annual SPEI had two extremely dry spells during 1936–1947 and 1978–2018. Japan, South Korea, and North Korea are wet in the summer compared to other regions of East Asia, with drought frequency occurring at 51.4%, respectively. The mean drought frequencies in China and Mongolia are 57.4% and 54.6%. China and Mongolia are the driest regions in East Asia due to high drought frequency and duration. The spatial seasonal analysis of solar radiation (SR), water vapor pressure (WVP), wind speed (WS), vegetation condition index (VCI), temperature condition index (TCI), and vegetation health index (VHI) have confirmed that the East Asia region suffered from maximum drought events. The seasonal variation of SPEI shows no clear drying trends during summer and autumn seasons. During the winter and spring seasons, there was a dry trend in East Asia region. During 1902–1990, a seasonal SPEI presented diverse characteristics, with clear wet trends in Japan, Mongolia, and North Korea in four different growing seasons, with dry trends in China and South Korea. During 1991–2018, seasonal SPEI presented clear dry trends in Japan, Mongolia, and North Korea in different growing seasons, while China and South Korea showed a wet trend during the spring, autumn, and winter seasons. This ecological and climatic mechanism provides a good basis for the assessment of vegetation and drought-change variations within East Asia. An understandings of long-term vegetation trends and the effects of rainfall and SPEI on droughts of varying severity is essential for water resource management and climate change adaptation. Based on the results, water resources will increase under global warming, which may alleviate the water scarcity issue in the East Asia region. [ABSTRACT FROM AUTHOR]

This paper seeks to measure farmers’ perceptions on climate variations, and examine the effects of such variations on cassava production in Ghana. Using a three-stage sampling technique involving cluster, stratified, and simple random sampling techniques, structured questionnaires were administered to 252 smallholder cassava farmers in the Awutu Senya District of the Central Region, Ghana. This was supplemented with focus group discussion sessions with male and female cassava farmers for the purpose of triangulating the quantitative and qualitative data. The study showed an overwhelming 98% of respondents, comprising 57% males, and 43% females, acknowledging to have noticed changes in the weather patterns over the last 30 years. While 85% of respondents said rainfall was decreasing, 75% said the rains did not come at the expected time, with 58% of them saying reduced rainy periods were the noticeable changes. Respondents attributed the changes in weather patterns to environmental degradation (72%), natural phenomenon (15%), and punishment by God (1%). Majority of them (97%) said they had suffered from decreasing yields in cassava as a result of seasonal variations in temperature and rainfall. The paper makes a strong case for activities that will bridge the knowledge-and-skill gap between male and female farmers.

Climate variation largely impacts migration in with the capacity to worsen conflict and security situations in parts of Africa, Nigeria in particularly, already facing security threats from the activities of sedentary and nomadic pastoral farmer’s interaction. Increasing variations in rainfall patterns significantly impact the migration patterns of vulnerable households and constitute a risk factor to their livelihoods. For effective adaptation plan and sustainable livelihood decision that has climate resilient future, there is need for better understanding of the conflict and security implications of climate variation. This paper, therefore, interrogates the nexus between climate variation and migration, as well as the impact of this nexus on conflicts and security of lives and properties in Nigeria. Using critical analysis and qualitative methodology, the study establishes that migration settlement policies that fail to define the rights and duties of settlers and those of indigenes of any particular community, create loopholes for the reification of identities and identity-induced crisis. The conclusion of the paper is that migration issues resulting from climate variation have not been adequately addressed to involve all stakeholders. There is the need to harvest environmental impact assessment data of climate variation to guide the provision of alternative options to climate-related emergencies across Nigeria.

Overexploitation of groundwater in urban karst aquifers can lead to negative consequences such as land subsidence, depletion of springs and lakes, and water pollution. It can also have indirect effects such as environmental, socio-economic, and political instability. In the municipality of Sete Lagoas, Brazil, the long-term effects of extensive groundwater extraction have been observed and studied over the years. This paper analyzes the response of the karst aquifer to urban, industrial, and climatological changes that may have contributed to changes in the aquifer over the last four decades. The results show that groundwater extraction has exceeded the average aquifer recharge since the year 2000. From the 1980s, the number of wells has steadily increased due to unplanned urban development, resulting in higher demand for groundwater. In the 2010s, pumping from tubular wells (7.39 × 107 m3/yr) exceeded the maximum recharge capacity of the aquifer (7.33 × 107 m3/yr). These wells are mainly concentrated in two areas: the central urban zone and the industrial sector. As a result, kilometer-long cones of depression have formed, changing the aquifer from confined to unconfined within these regions. According to the census data, about 67% of the wells remain unidentified. The average annual recharge to the aquifer is estimated to be 5.68 × 107 m3/yr, which accounts for 12% of the average annual rainfall in the region. Climatological trends indicate an incipient decrease in precipitation and an increase in temperature, suggesting a potential decrease in future aquifer recharge. In addition, only 17% of the area has high infiltration rates ranging from 35% to 75%. The current situation in Sete Lagoas is one of overexploitation of groundwater resources, which could be mitigated by localized reduction of groundwater consumption and implementation of effective management strategies to increase aquifer recharge. [Display omitted] • Central urban and industrial areas present kilometer-scale cones of depression. • Pumping from tubular wells has already exceeded the aquifer's maximum recharge. • Sete Lagoas is currently facing an overexploitation situation. • Reduction of consumption and effective management strategies shall increase recharge. [ABSTRACT FROM AUTHOR]

As climate conditions deteriorate, human health faces a broader range of threats. This study aimed to determine the risk of death from metabolic syndrome (MetS) due to meteorological factors. We collected daily data from 2014 to 2020 in Wuhu City, including meteorological factors, environmental pollutants and death data of common MetS (hypertension, hyperlipidemia and diabetes), as well as a total number of 15,272 MetS deaths. To examine the relationship between meteorological factors, air pollutants, and MetS mortality, we used a generalized additive model (GAM) combined with a distributed delay nonlinear model (DLNM) for time series analysis. The relationship between the above factors and death outcomes was preliminarily evaluated using Spearman analysis and structural equation modeling (SEM). As per out discovery, diurnal temperature range (DTR) and daily mean temperature (T mean) increased the MetS mortality risk notably. The ultra low DTR raised the MetS mortality risk upon the general people, with the highest RR value of 1.033 (95% CI: 1.002, 1.065) at lag day 14. In addition, T mean was also significantly associated with MetS death. The highest risk of ultra low and ultra high T mean occured on the same day (lag 14), RR values were 1.043 (95% CI: 1.010, 1.077) and 1.032 (95% CI: 1.003, 1.061) respectively. Stratified analysis's result showed lower DTR had a more pronounced effect on women and the elderly, and ultra low and high T mean was a risk factor for MetS mortality in women and men. The elderly need to take extra note of temperature changes, and different levels of T mean will increase the risk of death. In warm seasons, ultra high RH and T mean can increase the mortality rate of MetS patients. [ABSTRACT FROM AUTHOR]

How to distinguish the relative role of climate change and human activities in vegetation dynamics has attracted increasing attention. However, most of the current studies concentrate on arid and semiarid regions, while the relative contributions of climate change and human activities to vegetation changes remain unclear in warm-humid regions. Based on the normalized difference vegetation index (NDVI) and climatic variables (temperature, precipitation, radiation) during 2001–2020, this study used the Theil–Sen median trend analysis, partial correlation analysis, and residual trend analysis to analyze the spatiotemporal pattern of vegetation trends, the response of vegetation to climate variations, and the climatic and anthropogenic contributions to vegetation dynamics in the warm and humid Guangdong Province of south China. Results showed that the NDVI in most areas exhibited an increasing trend. Changes in climatic variables displayed different spatial variations which, however, were not significant in most areas. Vegetation responded diversely to climate change with temperature as the most important climatic factor for vegetation improvement in most areas, while precipitation was the dominant climatic factor in the southern edge region and radiation was the dominant climatic factor in the central and western regions. Vegetation in most areas was influenced by both climate change and human activities, but the contribution rate of human activities was commonly much higher than climate change. The findings of this study are expected to enhance our understanding of the relative climatic and anthropogenic contributions to vegetation changes in warm-humid regions and provide a scientific basis for future ecological policies and ecosystem management in highly urbanized regions. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to assess the local communities' perception of climate variation effects on crop production and the adopted strategies by farmers in order to cope with the negative effects of climate on the agriculture in the coastal zone of Benin. Design/methodology/approach – A total of 290 agricultural households were sampled and surveyed through structured interviews. The principal component analysis (PCA) was performed on the relative frequencies citation of perceived climate variation indication in order to describe the relationship between risk perceptions according to socio-demographic characteristics. The relative frequency of citation was calculated according to age, gender, ethnic group and agro-ecological region. Findings – Results showed that almost 83 per cent of the respondents already perceived the climate change risks through several indications. Climate variation perception varied with respect to age. Respondents' opinion regarding climate variation causes depended generally on their age, religion and level of education. As far as climate variation risks impact on crop production is concerned, the respondents' opinions diverged. Originality/value – The assessment of local communities' perception is important to design participatory and sustainable measures to cope with harmful effects of climate variation on crop production. [ABSTRACT FROM AUTHOR]

Highlights • An approach to link individual-tree and stand-level growth models was successfully developed. • The G & Y system results in full compatibility between the individual-tree and stand-level estimates. • The system is flexible to predict and project growth under different climate scenarios. • The system provides either stand-level or stand structure estimates. • The system is sensitive to clonal and climate variation. Abstract Linking individual-tree and stand-level growth models is required for estimating future forest stand structure, while maintaining the desired accuracy for forest management decision making. There is a scarcity of studies addressing this issue for clonal Eucalypt stands in Brazil. Thus, this paper aims to develop a compatible individual-tree and stand-level growth and yield system for clonal Eucalypt stands in Brazil. The dataset used in this study is derived from remeasurement information of sixteen TECHS sites. At every site, eleven Eucalypt clones were planted in single block plots, while extra plots under a rainfall exclusion regime were also installed in fourteen sites. Prediction and projection diameter percentile equations were developed, as well as an individual-tree mortality equation and a generalized height-diameter equation. In addition, a detailed explanation of the structural architecture of the developed compatible growth and yield system is provided. Differences when forecasting forest afforestation and updating forest inventories were highlighted in order to provide the proper use of the developed growth and yield system. Finally, the individual-tree equations were validated through the use of the rainfall exclusion regime plots as was the growth and yield system when applied for prediction and projection purposes. The individual-tree level equations provided accurate estimates. The newly developed compatible growth and yield system also displayed unbiased and accurate estimates. The system achieved full compatibility between individual-tree and stand-level estimates and produced accurate stand table estimates. The growth and yield system presented is a powerful analytical tool that can serve to update inventory data in tropical Brazil and also to provide estimates for expected forest afforestation. The system has the capability of providing detailed outputs, which allows forest managers to consider merchandizing the clonal Eucalypt stands into multiple products. [ABSTRACT FROM AUTHOR]

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This paper presents a novel framework comprising analytical, hydrological, and remote sensing techniques to separate the impacts of climate variation and regional human activities on streamflow changes in the Karkheh River basin (KRB) of western Iran. To investigate the type of streamflow changes, the recently developed DBEST algorithm was used to provide a better view of the underlying reasons. The Budyko method and the HBV model were used to investigate the decreasing streamflow, and DBEST detected a non-abrupt change in the streamflow trend, indicating the impacts of human activity in the region. Remote sensing analysis confirmed this finding by distinguishing land-use change in the region. The algorithm found an abrupt change in precipitation, reflecting the impacts of climate variation on streamflow. The final assessment showed that the observed streamflow reduction is associated with both climate variation and human influence. The combination of increased irrigated area (from 9 to 19% of the total basin area), reduction of forests (from 11 to 3%), and decreasing annual precipitation has substantially reduced the streamflow rate in the basin. The developed framework can be implemented in other regions to thoroughly investigate human vs. climate impacts on the hydrological cycle, particularly where data availability is a challenge. [ABSTRACT FROM AUTHOR]

Seasonal variations in temperature, rainfall and resource availability are ubiquitous and can exert strong pressures on population dynamics. Infectious diseases provide some of the best-studied examples of the role of seasonality in shaping population fluctuations. In this paper, we review examples from human and wildlife disease systems to illustrate the challenges inherent in understanding the mechanisms and impacts of seasonal environmental drivers. Empirical evidence points to several biologically distinct mechanisms by which seasonality can impact host–pathogen interactions, including seasonal changes in host social behaviour and contact rates, variation in encounters with infective stages in the environment, annual pulses of host births and deaths and changes in host immune defences. Mathematical models and field observations show that the strength and mechanisms of seasonality can alter the spread and persistence of infectious diseases, and that population-level responses can range from simple annual cycles to more complex multiyear fluctuations. From an applied perspective, understanding the timing and causes of seasonality offers important insights into how parasite–host systems operate, how and when parasite control measures should be applied, and how disease risks will respond to anthropogenic climate change and altered patterns of seasonality. Finally, by focusing on well-studied examples of infectious diseases, we hope to highlight general insights that are relevant to other ecological interactions. [ABSTRACT FROM AUTHOR]

In this paper, we examine the Early to Middle Holocene evolution of a prominent group of ground-water fed lakes in the southeastern hinterland of the Badain Jaran Desert (BJD) of northwest China. Specifically, we describe a sediment profile record from the Taoerlegetu (TR) palaeolake basin using multiple proxies of total organic carbon (TOC), total nitrogen (TN), C/N ratio, δ13C org , grain size and mineral composition based on a well-dated trench profile. As C/N values suggest that sedimentary organic matter mainly originated from aquatic plants, δ13Corg values can be used as a qualitative proxy for water level because aquatic plants in different biotopes (water depth) have different δ13C values. Our results show that from 10.9 to 9.1 cal kyr B.P., water level rose slowly, and aquatic macrophytes occupied the lake basin. From 9.1 to 5.5 cal kyr B.P., water level reached an even higher level and phytoplankton replaced macrophytes as the major contributor to organic matter. The humid episode of the lakes in the hinterland of the BJD in the early Holocene might be related to the increased groundwater supply from the northeast region of the Tibet Plateau. These findings are consistent with earlier studies of lacustrine and peat sediments found in periphery of the modern lake group, which indicate that their geographic extent may have been larger in the past. A relative drought period recorded in the studied succession from 8.5 to 8.0 cal kyr B.P. marks an interval of reduced ground-water transport from the Tibet Plateau. This interval probably corresponds to the "8.2 ka cold event" and provides evidence that this widespread climate episode influenced groundwater processes across inland Asia. • The δ13C org value could be used as a qualitative indicator for the change of water level. • Lakes in the hinterland of the Badain Jaran Desert shows different evolution progress with these in the edge. • The main water source of lakes in the hinterland of the BJD in the Early Holocene comes from the Tibet Plateau. [ABSTRACT FROM AUTHOR]

Evaluation of the long-term effect of ecosystem recovery projects is critical for future ecological management and sustainable development. The Three-North Shelterbelt (TNS) is a large-scale afforestation project in a crucial region of China. Numerous researchers have evaluated the vegetation ecological quality (VEQ) of the TNS using a single vegetation indicator. However, vegetation ecosystems are complex and need to be evaluated through various indicators. We constructed the vegetation ecological quality index (VEQI) by downscaling net primary productivity, leaf area index, fractional vegetation cover, land surface temperature, vegetation moisture, and water use efficiency of vegetation. The spatiotemporal characteristics and main contributing factors of VEQ in the TNS from 2000 to 2020 were investigated using SEN+Mann−Kendall, Hurst exponent, geographical detector, and residual trend analysis testing. The results suggest that VEQ in the TNS showed an improving trend over the 21-year study period. The areas with significant improvements were concentrated in the central and eastern parts of the TNS. Significant deterioration occurred only sporadically in various urban areas. Characteristics of future unsustainable VEQ trends could be detected across the TNS. Precipitation, vegetation type, soil type, elevation, and solar radiation exhibited the greatest impact on VEQ throughout the TNS. Human activities (e.g., afforestation and government investments) were the dominant factors and had a relative contribution of 65.24% to vegetation area change. Our results provide clues for assessing environmental recovery and sustainable development in other regions. [ABSTRACT FROM AUTHOR]

Understanding long‐term forest fire histories of boreal landscapes is instrumental for parameterizing climate–fire interactions and the role of humans affecting natural fire regimes. The eastern sections of the European boreal zone currently lack a network of annually resolved and centuries‐long forest fire histories. To fill in this knowledge gap, we dendrochronologically reconstructed the 600‐year fire history of a middle boreal pine‐dominated landscape of the southern part of the Republic of Komi, Russia. We combined the reconstruction of fire cycle (FC) and fire occurrence with the data on the village establishment and climate proxies and discussed the relative contribution of climate versus human land use in shaping historic fire regimes. Over the 1340–1610 ce period, the territory had a FC of 66 years (with the 90% confidence envelope of 56.8 and 78.6 years). Fire activity increased during the 1620–1730 ce period, with the FC reaching 32 years (31.0–34.7 years). Between 1740–1950, the FC increased to 47 years (41.9–52.0). The most recent period, 1960–2010, marks FC's historic maximum, with the mean of 153 years (102.5–270.3). Establishment of the villages, often as small harbors on the Pechora River, was associated with a non‐significant increase in fire occurrence in the sites nearest the villages (p = 0.07–0.20). We, however, observed a temporal association between village establishment and fire occurrence at the scale of the whole studied landscape. There was no positive association between the former and the FC. In fact, we documented a decline in the area burned, following the wave of village establishment during the second half of the 1600s and the first half of the 1700s. The lack of association between the dynamics of FC and the dates of village establishments, and the significant association between large fire years and the early and latewood pine chronologies, used as historic drought proxy, indirectly suggests that the climate was the primary control of the landscape‐level FCs in the studied forests. Pine‐dominated forests of the Komi Republic may hold a unique position as the ecosystem with the shortest history of human‐related shifts in fire cycles across the European boreal region. [ABSTRACT FROM AUTHOR]

The atmosphere plays a significant role in degrading Ka‐band (32 GHz) radio and optical communications for single antenna communications as well as degrading interferometric measurements such as used for radio astronomy and multi‐antenna arrays. Higher frequencies such as deep space Ka‐band (32 GHz) and near‐Earth K‐band (26 GHz) are more susceptible to this atmospheric degradation than at the lower frequency bands of S‐band (2.3 GHz) and X‐band (8.4 GHz). The various sources of atmospheric degradation include rain attenuation, cloud attenuation, gaseous attenuation, atmospheric noise temperature increase, and scintillation. For this study, we have focused on the strength of the turbulence caused principally by the wet atmosphere represented by the refractive index structure parameter Cn2, which is a measure of the variance of the refractive index over small incremental distances along the signal path, and thus is a strong function of water vapor variations at microwave frequencies. Here we provide a comprehensive study of this parameter derived from years of Site Test Interferometer measurements acquired from a variety of climates. We found that the strongest diurnal variation and correlation of Cn2 measurements with its model occurred for Goldstone, California representing a high‐desert climate, while weaker correlations were found for Kennedy Space Center representing a sub‐tropical climate, and Canberra, Australia and Madrid, Spain representing temperate climates. We quantified periods where the strongest correlation was observed such as Goldstone summers (as high as 0.7 for ∼3‐day periods) where the days are typically hot and humid while nights tend to be colder and drier. Key Points: Refractive index structure constants were derived from Site Test Interferometer (STI) phase delay scatter for a variety of climatesThe strongest diurnal variation in this parameter occurred for the high‐desert site at Goldstone, CaliforniaWe found good correlation with the derived STI structure parameters and a model which included planetary boundary layer height [ABSTRACT FROM AUTHOR]

Vegetation is a sensitive factor in marsh ecosystems, which can provide nesting sites, foraging areas, and hiding places for waterfowl and can affect their survival environment. The Jilin Momoge National Nature Reserve, which consists of large areas of marshes, is located in the semi-arid region of northeast China and is an important stopover site for the critically endangered species of the Siberian Crane (Grus leucogeranus). Global climate change, extreme droughts and floods, and large differences in evaporation and precipitation in this region can cause rapid vegetation succession. In recent years, increased grain production and river-lake connectivity projects carried out in this area to increase grain outputs and restore wetlands have caused significant changes in the hydrological and landscape patterns. Therefore, research on the response of variation trends in vegetation patterns to the main driving factors (climate change and human activities) is critical for the conservation of the Siberian Crane. Based on the Google Earth Engine (GEE) platform, we obtained and processed the Normalized difference vegetation index (NDVI) data of the study area during the peak summer vegetation period for each year from 1984 to 2020, estimated the annual vegetation cover using Maximum value composites (MVC) method and the image dichotomy method, calculated and analyzed the spatial and temporal trends of vegetation cover, explored the response of vegetation cover change in terms of climate change and human activities, and quantified the relative contribution of both. The results revealed that first, from the spatial and temporal changes, the average annual growth rate of regional vegetation was 0.002/a, and 71.14% of the study area was improved. The vegetation cover showed a trend of degradation and then recovery, in which the percentage of high vegetation cover area decreased from 51.22% (19842000) to 28.33% (2001-2005), and then recovered to 55.69% (2006-2020). Second, among climate change factors, precipitation was more correlated with the growth of vegetation in the study area than temperature, and the increase in precipitation during the growing season could promote the growth of marsh vegetation in the Momoge Reserve. Third, overall, human activities have contributed to the improvement of vegetation cover in the study area with the implementation of important ecological projects, such as the return of farmland to wetlands, the return of grazing to grass, and the connection of rivers and lakes. Fourth, climate change and human activities jointly drive vegetation change, but the contribution of human activities in both vegetation improvement and degradation areas (85.68% and 78.29%, respectively) is higher than that of climate change (14.32% and 21.71%, respectively), which is the main reason for vegetation improvement or degradation in the study area. The analysis of vegetation pattern change within an intensive time series in semi-arid regions can provide a reference and basis for studying the driving factors in regions with rapid changes in vegetation and hydrological conditions. [ABSTRACT FROM AUTHOR]

Identifying the relative contributions of climate change and human activities to alpine grassland dynamics is critical for understanding grassland degradation mechanisms. In this study, first, the actual NPP (NPPa) was obtained by MOD17A3. Second, we used the Zhou Guangsheng model to simulate the potential met net primary productivity (NPPp). Finally, the NPP generated by anthropogenic activities (NPPh) was estimated by calculating the difference between NPPp and NPPa. Then, the relative contributions of climate change and human activities to NPP changes in grasslands were quantitatively assessed by analyzing trends in NPPp and NPPa. Thereby, the drivers of NPP change in the Yellow River source grassland were identified. The results showed that the temperature and precipitation in the study area showed a warm-humid climate trend from 2000 to 2020. The NPPp and NPPa increased at a rate of 1.07 g C/m2 and 1.51 g C/m2 per year, respectively, while the NPPh decreased at a rate of 0.46 g C/m2 per year. It can be seen that human activities had a positive effect on the change of NPP in the Yellow River source grassland from the change rate. The relative contribution analysis showed that 55.90% of grassland NPP increased due to climate change, 40.16% of grassland NPP increased due to human activities, and the grassland degradation was not significant. The research results can provide a theoretical basis and technical support for the next step of the Yellow River source grassland ecological protection project. [ABSTRACT FROM AUTHOR]

Southeast Asian countries have the possibility to have rainfall and number of extreme rainfall event change due to future climate variation. This paper proposed three extreme rainfall indices as a modification of climate extremes indices from CLIMDEX Project by researchers at the Climate Change Research Centre (CCRC), the University of New South Wales (UNSW). The proposed indices aim to be used as a parameter for observing extreme rainfall events in tropical monsoon countries. Eleven extreme precipitation indices from CLIMDEX Project and the three proposed extreme precipitation for tropical monsoon countries are systematically analyzed based on data of daily rainfall from meteorological stations in Bangkok and Jakarta. Mann-Kendall test was used to observe the trend of extreme rainfall. In general, the analysis of a total of 14 extreme indices show both Bangkok and Jakarta received more rainfall during rainy season and less rainfall during dry season. Specifically, a significant increasing trend of extreme rainfall indices (R60 and R80) was revealed using the proposed indices. [ABSTRACT FROM AUTHOR]

Abstract: During the last decade there has been considerable interest in the stochastic analysis of temperature trends. This attention usually focuses upon global and hemispheric time series. Analyses of global temperatures are of obvious importance but it is equally of interest to analyse questions of warming at a more ‘micro’ level. The objective of the paper is to illustrate that the appropriate estimation of a local record trend component necessitates the use of flexible methods. A long time series of temperature data from a Mediterranean urban area is analysed. The data comprise a series on monthly mean surface temperatures for Valencia (Spain), a Mediterranean city in terms of its urban structure and climatology. Trends are extracted from the temperature data available from 1938, using both annual and seasonal averages. Attention is focused on applying non-parametric methods which allow the analysis of non stationary trends in comparison to other methods. A local polynomial regression fitting and wavelet thresholding indicate that there is an upward trend in the annual series. The bandwidth in the local regression model selected by cross-validation follows short-term cycles rather than tracing out the long-term component. Therefore to extract the long-term trend a higher smoothing parameter is selected. The trend visualization plots show that the increase in the mean temperature per year is non-stationary. A change-point detection test indicates a trend change in the series around the year 1968. There is compelling evidence of a trend increase after this year, which is probably due to increase urbanization. The analysis of monthly observations is also discussed. Seasonal differences in trend patterns are more clearly observed when the monthly data are averaged across seasons. There have been upward shifts in the trends of spring and summer temperatures. [Copyright &y& Elsevier]

Abstract: Type conversions of vegetation are often triggered by changes in one or more limiting environmental factors. Such changes are particularly evident along montane forest-meadow ecotones, where historical changes in fire, grazing and climate have occurred. In this paper, we reconstruct spatial and temporal variation in climate, livestock grazing and fire for 11 meadow inclusions in the pine-dominated forest of northeastern California, USA. We then compare this environmental variation to temporal patterns of tree invasion by dating the establishment of 1420 trees, saplings and seedlings. Invasive trees included ponderosa pine (Pinus ponderosa Laws.), Jeffrey pine (Pinus jeffreyi Grev and Balf.), lodgepole pine (Pinus contorta var. murrayana Loudon (Grev and Balf.)) and western juniper (Juniper occidentalis Hook.). Before the arrival of Euro-Americans in 1849, fires burned with a median interval of 11 years based on 1–3ha composite records from multiple trees, and 14 years using records from individual trees. There was substantial variation in the date of the last recorded fire within and among meadows, but fire was rare after 1905. The onset of tree establishment varied among meadows, but followed the reduction and removal of fire. Livestock grazing also varied among meadows, and the highest establishment rates occurred when grazing was moderate. Mean tree establishment was 22.9 trees/ha/decade during the late 19th century when grazing was unregulated, 62.6 trees/ha/decade when sheep were present, but regulated, and 40.7 trees/hectare/decade after sheep were replaced with cattle. Ponderosa and Jeffrey pine established during a range of temperature and precipitation conditions, but establishment was greater when summer precipitation was below normal, annual temperatures were normal and springs were cool. Although changes in disturbance and climate were associated with tree establishment, the persistence of trees at the meadow edge is best explained by continued fire exclusion. With the long-term absence of fire the local effects of different disturbance histories are being lost. [Copyright &y& Elsevier]

Relative role of intrinsic density-dependent factors (such as inter-and intraspecific competition, predation) and extrinsic density-independent factors (environmental changes) in population dynamics is a key issue in ecology. Density-dependent mechanisms are considered as important drivers of population dynamics in many vertebrate and insect species; however, their influence on the population dynamics of freshwater invertebrates is not clearly understood. In this study, I examined interannual variations in the abundance of the glacial relict amphipod Monoporeia affinis in a small subarctic lake based on long-term (2002-2019) monitoring data. The results suggest that the population dynamics of amphipods in the lake is influenced by the combined effects of both intrinsic and extrinsic factors. The reproductive success of amphipod cohorts was inversely related to its initial abundance, indicating it is influenced by density-dependent factors. M. affinis recruitment was negatively correlated with population density and near-bottom temperature but positively correlated with food availability, which is defined as the concentration of chlorophyll a. Multiple regression with chlorophyll, temperature, and abundance of parent cohort as independent factors explained about 80% of the variation in the reproductive success of amphipods. The negative correlation between amphipod recruitment and water temperature indicates that the current climate conditions adversely affect the populations of glacial relict amphipods even in cold-water lakes of the subarctic zone. Results of this study can be useful in environmental assessments to separate population oscillations connected with density-dependent mechanisms from human-mediated changes. [ABSTRACT FROM AUTHOR]

This paper addresses variations in the wind climate in relation to changes in the impact of wind erosion on agricultural lands with Scania, the southernmost province of Sweden, as an example. The literature concerning wind erosion in the region is reviewed and the conclusions are linked to recent analyses of the regional wind climate. Presently, wind erosion occasionally induces problems in light soil areas of the intensively cultivated Scania. It is not a new phenomenon that results from modern farming practice; it was documented already in the 18th century. This was an era of major land use changes because the increasing population required new and more vulnerable areas to be cultivated, which resulted in an ecological crisis due to increased wind erosion. Partly overlapping in time, a series of land amalgamation reforms transformed the land-use resulting in larger fields. Analyses of the frequency of wind directions indicate that variations in the large-scale wind climate occurred at that time. Wind erosion again became a topic of concern in the 20th century. Extensive analyses of several aspects of the wind climate (e.g., storminess and cyclone intensity) of Scandinavia and northwestern Europe show that there have been interdecadal variations but no sign of an overall long-term trend. The recurring periods of intensified wind erosion problems can best be explained as the combined result of a varying wind climate and the lack of appropriate long-term maintenance strategies for protective measures through the intervening periods of benign wind climate. [Copyright &y& Elsevier]