Special Issue on "Response of Polar Organisms and Natural Environment to Global Changes"

High altitude and high latitude regions on Earth are experiencing rapid changes in climate, with impacts on polar organisms and the environment. The persistent cold and sometimes inhospitable conditions create unique ecosystems and habitats for polar organisms.

Inviting Contributions to a Special Issue on "Response of Polar Organisms and Natural Environment to Global Changes"

Dear Colleagues, We would like to invite you to submit manuscripts to a special issue of the journal Advances in Polar Science （APS） on ＂Response of Polar Organisms and Natural Environment to Global Changes＂.

Global Changes

A review of the year’s international political and security situation In 2010, despite the generally stable international environment, significant changes occurred seen in international relations. This is due

GLOBAL CLIMATE CHANGES AND THE TOURISM OF CHINA

The future global climate changes induced by the increased atmospheric CO2 concentration is receiving much attention from the scientific community as well as the public. Model simulations and palaeoclimatic data studies show an evident change in temperature and precipitation over China will occur under conditions of the global warming. Possible scenarios of the future climates are given here for China on the basis of synthesizing model simulations and palaeoclimatic data. Most parts of China will experience an increase in temperature, but the warming may be more remarkable in winter in h1e northern half of the country. Increase in precipitation will be seen in nearly every parts of the eastern China, and it will be larger in North and Northeast China. Impacts of the climate changes on the national tourism are assessed. Regions suitable for tourisin development in terms of climate comfortable index will shift northward. Some scenic spots and toruism facilities will be damaged due to sea level rise and increased rainfall. Some regions will benefit from the dimate change, but the tourism industry as a whole will be negatively affected.

LATE QUATERNARY ENVIRONMENTAL CHANGES IN THE ANTARCTIC AND THEIR CORRELATION WITH GLOBAL CHANGE

Two ingressions occurred in the last glacial interstadial (50,00-25,000 a BP) and Holocene optimum (7,500-5,000 a BP) periods in Antercticregion. The grea expansion of Antarcic Ice Sheet appeared at last glacialmaximum (18,000 a BP) when Antarctic sea level was 100- 150 m lower thanthat at presat. Three times of glacial advances and rotreas occurred on thefront of Antarctic Ice Shed since 3,000 a BP. All these phenomena werecoordinated with global changes. In the past decades, records from Antercticice-free areas and ice cores testified that mvironmedl and climatic changesin Antarctic region have been coordinated with global changes since latePlelstocene. In the past decades, Antarctic inland was a little warming up andthe fron of the ice shed was slowly melting and ratreating due to the increaseof CO2 content in the atmosphere. The greenhouse effect will cause AntercticIce Sheet (especially on the ice shelves) to be partly melting away, but can notdestroy it. In this case the amplitude of sea level rise caused by the melting ofAntarctic ice will be less than 0.2 m within the coming five decades.

Predicting plant-soil N cycling and soil N_(2)O emissions in a Chinese old-growth temperate forest under global changes:uncertainty and implications

Soil-emitted N_(2)O contributes to two-thirds of global N_(2)O emissions,and is sensitive to global change.We used DayCent model to simulate major plant-soil N cycling processes under different global change scenarios in a typical temperate mixed forest in north-eastern China.Simulated scenarios included warming(T),elevated atmospheric CO_(2) concentration([CO_(2)])(C),increased N deposition(N)and precipitation(P),and their full factorial combinations.The responses of plant-soil nitrogen cycling processes including net N mineralization,plant N uptake,gross nitrification,denitrification and soil N_(2)O emission were examined.Concurrent increase of elevated[CO_(2)]and N deposition displayed most strong interactive effects on most fluxes.Using the results from experimental studies for evaluation,simulation uncertainty was highest under elevated[CO_(2)]and increased precipitation among the four global change factors.N deposition had a fundamental impact on soil N cycle and N_(2)O emission in our studied forest.Despite forest soil acting as a N sink for added N,scenarios which included increased N deposition showed higher cumulative soil N_(2)O emissions(summed up from 2001 to 2100).In particular,the scenario which included T,P,and N had the largest cumulative soil N_(2)O emission,which was a 24.4% increase over that under ambient conditions.Our study points to the importance of the interactive effects of global change factors on plant-soil N cycling and the necessity of multi-factor manipulation experiments.

Lightning Changes in Response to Global Warming in Rio de Janeiro, Brazil

Physical concepts based on the Clausius-Clapeyron relation and on the thermodynamics and aerosol characteristics associated with updrafts, global climate models assuming different parametrizations and lightning-related output variables, and lightning-related data (thunderstorm days) are being used to infer the lightning incidence in a warmer planet, motivated by the global warming observed. In all cases, there are many gaps to be overcome making the lightning response to the global temperature increase still unpredicted. Values from almost 0% (no increase) to 100% have been estimated, being 10% the most common value. While the physical concepts address only part of the problem and the global climate models need to make many simple assumptions, lightning-relate data have strong time and space limitations. In this context, any new evidence should be considered as an important contribution to better understand how will be the lightning incidence in the future. In this article, we described new results about the occurrence of thunderstorms from 1850 to 2010 (a period of 160 years) in the city of Rio de Janeiro, in the Southeast of Brazil. During this period thunderstorm days were recorded in the same location, making this time series one of the longest series of this type available worldwide. The data support an increase of 21% in the mean annual thunderstorm days during the period, while surface temperature increased by 0.6°C during the period. Considering that the mean annual number of thunderstorm in the beginning of this period was 29, we found an increase of one thunderstorm day per 0.1°C of increase in the surface temperature. Assuming that the number of lightning flashes per thunderstorm remains approximately constant during the period, this number corresponds to an increase in the lightning flash rate of approximately 35% per °C of increase of temperature. In addition, considering that the increase of the global temperature during the period was almost the same that observed in Rio de Janeiro, we can conclude that this increase in the lightning flash rate is due to the global warming with no effect of urban activity. Finally, we found that monthly thunderstorm days and monthly mean surface temperature show a linear correlation with a coefficient of 0.9 along the period.

Critical role of multidimensional biodiversity in contributing to ecosystem sustainability under global change

The 21st century has seen an acceleration of global change,including climate change,elevated carbon dioxide,nitrogen deposition,and land-use intensification,which poses a significant threat to ecosystem functioning.Nev-ertheless,studies on the relationship between biodiversity and ecosystem functioning(BEF)have consistently demonstrated that biodiversity enhances ecosystem functioning and its stability,even in variable environmental conditions.These findings potentially indicate the critical role of biodiversity in promoting sustainable provi-sioning of ecosystem functioning under global change.Our paper provides a comprehensive review of current BEF research and the response of BEF to multiple global change factors.We demonstrate that(1)assessing the effects of biodiversity on ecosystem functioning requires consideration of multiple dimensions of diversity,such as diversity across multiple trophic levels(plants,animals,and microbes),multiple facets(taxonomy,functional traits,and phylogeny),and multiple spatial scales(local,regional,and landscape scales).(2)The interaction of multiple global change factors may lead to a greater reduction in biodiversity and ecosystem functioning than a single global change factor.(3)Multidimensional biodiversity regulates the response of ecosystem functioning to global change factors,indicating that high levels of multidimensional biodiversity can mitigate the negative impacts of global change on ecosystem functioning.Overall,we emphasize that recognizing the importance of multidimensional biodiversity is critical for sustaining ecosystem functioning.Therefore,prioritizing conserva-tion efforts to maintain and enhance all dimensions of biodiversity is essential to address the challenges of future global change.

Global Effect of Climate Change on Seasonal Cycles,Vector Population and Rising Challenges of Communicable Diseases:A Review

This article explains ongoing changes in global climate and their effect on the resurgence of vector and pathogen populations in various parts of the world.Today,major prevailing changes are the elevation of global temperature and accidental torrent rains,floods,droughts,and loss of productivity and food commodities.Due to the increase in water surface area and the longer presence of flood water,the breeding of insect vectors becomes very high;it is responsible for the emergence and re-emergence of so many communicable diseases.Due to the development of resistance to chemicals in insect pests,and pathogens and lack of control measures,communicable zoonotic diseases are remerging with high infectivity and mortality.This condition is becoming more alarming as the climate is favoring pathogen-host interactions and vector populations.Rapid changes seen in meteorology are promoting an unmanageable array of vector-borne infectious diseases,such as malaria,Japanese encephalitis,filarial,dengue,and leishmaniasis.Similarly,due to unhygienic conditions,poor sanitation,and infected ground and surface water outbreak of enteric infections such as cholera,vibriosis,and rotavirus is seen on the rise.In addition,parasitic infection ascariasis,fasciolosis,schistosomiasis,and dysentery cases are increasing.Today climate change is a major issue and challenge that needs timely quick solutions.Climate change is imposing non-adaptive forced human migration territorial conflicts,decreasing ecosystem productivity,disease outbreaks,and impelling unequal resource utilization.Rapid climate changes,parasites,pathogens,and vector populations are on the rise,which is making great threats to global health and the environment.This article highlighted the necessity to develop new strategies and control measures to cut down rising vector and pathogen populations in endemic areas.For finding quick solutions educational awareness,technology up-gradation,new vaccines,and safety measures have to be adopted to break the cycle of dreadful communicable diseases shortly.

Semantic Segmentation of the Intertidal Zone of an Estuary—In Search of the Best Solution

An aerial photographic coverage acquired on two consecutive days in October 2021 with a ground resolution of 20 cm and a spectral resolution of 4 bands (red, green, blue and near infrared), allowed to distinguish most of the classes of interest present in the intertidal zone of the Sado estuary. We explored the possibilities of thematic classification in the powerful and complex software ArcGIS Pro;we presented the methodology used in a detailed way that allows others with minimal knowledge of GIS to reproduce the classification process without having to decipher the specifics of the software. The classification implemented used ground truth from four classes related to the macro-occupations of the area. In a first phase we explore the standard algorithms with object-based capabilities, like K-Nearest Neighbor, Random Trees Forest and Support Vector Machine, and in a second phase we proceed to test three deep learning classifiers that provide semantic segmentation: a U-Net configuration, a Pyramid Scene Parsing Network and DeepLabV3. The resulting classifications were quantitatively evaluated with a set of 500 control points in a test area of 37,500 × 12,500 pixels, using confusion matrices and resorting to Cohen’s kappa statistic and the concept of global accuracy, achieving a Kappa in the range [0.72, 0.81] and a global accuracy between 88.9% and 92.9%;the option U-Net had the most interesting results. This work establishes a methodology to provide a baseline for assessing future changes in the distribution of Sado estuarine habitats, which can be replicated in other wetland ecosystems for conservation and management purposes.

Asian Hydroclimate Changes and Mechanisms in the Preboreal from an Annually-laminated Stalagmite, Daoguan Cave, Southern China

One-year-resolved and annually-counted stalagmite multi-proxies （j180, ~13C, and layer width） from Daoguan Cave, Guizhou Province revealed detailed variability regarding the Asian Summer Monsoon （ASM） and local humidity across Bond events （BE） in the PreboreaL During BEs 8 and 7, 1.5%o enrichments in jlSo values were generally consistent with high- to low-latitude climate changes. In detail, the decadal-scale minor j180 oscillations in BE8 were broadly less than the mean value, in contrast to the significant changes in local soil moisture derived from the j13C values and layer records. In the mid-BE7, jlSo variability was generally above the average level, and higher- amplitude variations were observed in the three proxy indicators. Wavelet analysis on the total jlSo time series and across the specific time windows of BEs 8 and 7 identified periodicities of about 130, 60, and 20-a, respectively. Exceptionally strong in BE7, the 60-a cycle, pervasively observed in instrumental studies, became prominent starting at 11.4 kaBP. Thus, glacial background conditions are important for suppressing the ASM intensity in BE8, while during BE7, tropical hydrological circulations were potentially actively involved. Consequently, climate internal oscillations, analogous to modern conditions, might have occurred in the distant past once the link between the tropical ocean and atmosphere was established as occurs today.

How Could Agricultural Land Systems Contribute to Raise Food Production Under Global Change?

To feed the increasing world population, more food needs to be produced from agricultural land systems. Solutions to produce more food with fewer resources while minimizing adverse environmental and ecological consequences require sustainable agricultural land use practices as supplementary to advanced biotechnology and agronomy. This review paper, from a land system perspective, systematically proposed and analyzed three interactive strategies that could possibly raise future food production under global change. By reviewing the current literatures, we suggest that cropland expansion is less possible amid iferce land competition, and it is likely to do less in increasing food production. Moreover, properly allocating crops in space and time is a practical way to ensure food production. Climate change, dietary shifts, and other socio-economic drivers, which would shape the demand and supply side of food systems, should be taken into consideration during the decision-making on rational land management in respect of sustainable crop choice and allocation. And ifnally, crop-speciifc agricultural intensiifcation would play a bigger role in raising future food production either by increasing the yield per unit area of individual crops or by increasing the number of crops sown on a particular area of land. Yet, only when it is done sustainably is this a much more effective strategy to maximize food production by closing yield and harvest gaps.

Soil carbon pool in China and its global significance

Soil organic carbon density and its related characteristics of 41 soil types all over China were analyzed by using data of 745 soil profiles , and size of soil carbon pool was estimated. As a result, area-weighted averages of these 41 soil types for bulk density, profile depth, organic carbon content and profile carbon were 1. 24 tC/m3, 86. 2 cm, 3. 04% and 19. 7 kg C/m2 respectively. Total size of soil carbon pool was 185. 68 × 1009tC, which is 29 times of that in terrestrial biomass of China and 12. 6% of global soil carbon pools. Because of its huge carbon pool, soil of China plays an important role in global carbon cycle.

A New Indicator for Global Food Security Assessment: Harvested Area Rather Than Cropland Area

Cropland area has long been used as a key indicator of food security.However,grain yield is not solely controlled by the area of the cropland.Therefore,we proposed a new indicator to assess food security.Results show that from 1992 to 2004,the global cropland area increased by 840200 km^(2)(99.4%),but the grain yield increased only by 310 million t(29.1%);and from 2004 to 2015,the cropland area decreased by 39000 km^(2)(4.64%),but the grain yield increased by 370 million t(70.84%).This result showed that grain yield was not linearly correlated with cropland area,and delimiting the threshold of cropland protection may not guarantee food security.Combined with further correlation analysis,we found that the increase in the global grain yield was more closely related to the harvested area(R^(2)=0.94),which indicated that the harvested area is a more scientific and accurate indicator than cropland area in terms of guaranteeing food security.Therefore,if governments want to ensure the food security,they should choose a new and more accurate indicator:harvested area rather than cropland area.

Fire cycle of the Canada's boreal region and its potential response to global change

Interactions of fire cycle and plant species＇ reproductive characteristics could determine vegetation distribution pattern of a landscape. In Canada＇s boreal region, fire cycles before the Little Ice Age （c. 1850s） ranged from 30-130 years and 25-234 years afterwards until the settlement period （c. 1930s） when longer fire cycles occurred in response to climatic change and human interference. Analysis indicated that fire cycles were correlated with growing season （April-October） temperature and precipitation departure from the 1961-1990 normal, varying by regions. Assuming that wildfires will respond to future warming similar to the manner during the past century, an assessment using climatic change scenarios CGCMI, CGCM2 and HadCM2 indicates fire cycles would divert to a range of 80-140 years in the west taiga shield, more than 700 years for the east boreal shield and east taiga shield, and 300-400 years for the boreal plains in 2050.

Spatial and temporal variation of global LAI during 1981-2006

Earth is always changing. Knowledge about where changes happened is the first step for us to understand how these changes affect our lives. In this paper, we use a long-term leaf area index data （LAI） to identify where changes happened and where has experienced the strongest change around the globe during 1981-2006. Results show that, over the past 26 years, LAI has generally increased at a rate of 0.0013 per year around the globe. The strongest increasing trend is around 0.0032 per year in the middle and northern high latitudes （north of 30°N）. LAI has prominently increased in Europe, Siberia, Indian Peninsula, America and south Canada, South region of Sahara, southwest corner of Australia and Kgalagadi Basin; while noticeably decreased in Southeast Asia, southeastern China, central Africa, central and southern South America and arctic areas in North America.

Impact of land use/cover changes on carbon storage in a river valley in arid areas of Northwest China

Soil carbon pools could become a CO_2 source or sink, depending on the directions of land use/cover changes. A slight change of soil carbon will inevitably affect the atmospheric CO_2 concentration and consequently the climate. Based on the data from 127 soil sample sites, 48 vegetation survey plots, and Landsat TM images, we analyzed the land use/cover changes, estimated soil organic carbon（SOC） storage and vegetation carbon storage of grassland, and discussed the impact of grassland changes on carbon storage during 2000 to 2013 in the Ili River Valley of Northwest China. The results indicate that the areal extents of forestland, shrubland, moderate-coverage grassland（MCG）, and the waterbody（including glaciers） decreased while the areal extents of high-coverage grassland（HCG）,low-coverage grassland（LCG）, residential and industrial land, and cultivated land increased. The grassland SOC density in 0–100 cm depth varied with the coverage in a descending order of HCG〉MCG〉LCG.The regional grassland SOC storage in the depth of 0–100 cm in 2013 increased by 0.25×1011 kg compared with that in 2000. The regional vegetation carbon storage（S_（rvc）） of grassland was 5.27×10~9 kg in2013 and decreased by 15.7% compared to that in 2000. The vegetation carbon reserves of the under-ground parts of vegetation（S_（ruvb）） in 2013 was 0.68×10~9 kg and increased by approximately 19.01%compared to that in 2000. This research can improve our understanding about the impact of land use/cover changes on the carbon storage in arid areas of Northwest China.

THE DIRECT EFFECTS OF AEROSOLS AND DECADAL VARIATION OF GLOBAL SEA SURFACE TEMPERATURE ON THE EAST ASIAN SUMMER PRECIPITATION IN CAM3.0

Using the CAM3.0 model, we investigated the respective effects of aerosol concentration increasing and decadal variation of global sea surface temperature(SST) around year 1976/77 on the East Asian precipitation in boreal summer. By doubling the concentration of the sulfate aerosol and black carbon aerosol separately and synchronously in East Asia(100-150 °E, 20-50 °N), the climate effects of these aerosols are specifically investigated. The results show that both the decadal SST changing and aerosol concentration increasing could lead to rainfall decreasing in the center of East Asia, but increasing in the regions along southeast coast areas of China. However, the different patterns of rainfall over ocean and lower wind field over Asian continent between aerosol experiments and SST experiments in CAM3.0 indicate the presence of different mechanisms. In the increased aerosol concentration experiments, scattering effect is the main climate effect for both sulfate and black carbon aerosols in the Eastern Asian summer. Especially in the increased sulfate aerosol concentration experiment, the climate scattering effect of aerosol leads to the most significant temperature decreasing, sinking convection anomalies and decreased rainfall in the troposphere over the central part of East Asia. However, in an increased black carbon aerosol concentration experiment, weakened sinking convection anomalies exist at the southerly position. This weakened sinking and its compensating rising convection anomalies in the south lead to the heavy rainfall over southeast coast areas of China. When concentrations of both sulfate and black carbon aerosols increase synchronously, the anomalous rainfall distribution is somewhat like that in the increased black carbon concentration aerosol experiment but with less intensity.

Markers for Global Climate Change and Its Impact on Social, Biological and Ecological Systems: A Review

Present article sketches out major climate induced changes in marine, aquatic and terrestrial life. Few important biomarkers such as ecological, meteorological, socioeconomic, thermal, biophysical and biological, behavioral markers of climate change and global environmental stress have been highlighted to predict the future challenges and finding appropriate solutions. Though, so many climate change induced effects are visible but few unpredictable effects may be seen in future. Therefore, all such effects have been acknowledged, and tried to find appropriate solutions. Most visible effect is collection of high amounts of carbon dioxide in the atmosphere which is responsible for green house effect and causing natural calamities round the globe. It is not only jeopardized the survival of terrestrial, fresh water animals mainly planktons, bottom dwellers;coral reefs, algae, fish fauna in marine environment belong to different taxon but also responsible for disruption of ocean’s food web due to non-assimilation of extra carbon dioxide by the ocean water. There is a sharp decline in fresh water and sea shore micro-flora and micro-fauna. Other major visible effects are loss of biodiversity, depletion of forests, land degradation, severe floods and draughts. On other hand sudden changes in weather conditions causing irreparable devastations due to hurricanes and typhoons, storms, lightening, earthquakes and tsunamis are normally on rise. Both economic and ecological breakdowns are occurring more frequently which are more impactful and persistent. Climate change is major human health stressor;it is making fragmentation of socio-cultural bonds and reducing fertility of soil finally crop production. Climate change is imposing non-adaptive forced human migration, territorial conflicts, decreasing ecosystem productivity, disease out breaks, and impelling unequal resource utilization.

Relationship of underground water level and climate in Northwest China’s inland basins under the global climate change:Taking the Golmud River Catchment as an example

To identify the response of groundwater level variation to global climate change in Northwest China’s inland basins,the Golmud River Catchment was chosen as a case in this paper.Approaches of time series analysis and correlation analysis were adopted to investigate the variation of groundwater level influenced by global climate change from 1977 to 2017.Results show that the temperature in the Golmud River Catchment rose 0.57℃ every 10 years.It is highly positive correlated with global climate temperature,with a correlation coefficient,0.87.The frequency and intensity of extreme precipitation were both increased.Generally,groundwater levels increased from 1977 to 2017 in all phreatic and confined aquifers and the fluctuation became more violent.Most importantly,extreme precipitation led to the fact that groundwater level rises sharply,which induced city waterlogging.However,no direct evidence shows that normal precipitation triggered groundwater level rise,and the correlation coefficients between precipitation data from Golmud meteorological station located in the Gobi Desert and groundwater level data of five observation wells are 0.13,0.02,−0.11,0.04,and−0.03,respectively.This phenomenon could be explained as that the main recharge source of groundwater is river leakage in the alluvial-pluvial Gobi plain because of the high total head of river water and goodness hydraulic conductivity of the vadose zone.Data analysis shows that glacier melting aggravated because of local temperature increased.As a result,runoff caused groundwater levels to ascend from 1977 to 2017.Correlation coefficients of two groundwater wells observation data and runoff of Golmud River are 0.80 and 0.68.The research results will contribute to handling the negative effects of climate change on groundwater for Northwestern China.