Temporal and Spatial Characteristics of Climate Changes in the Urumqi River Basin of Tianshan Mountain over 50 years

Based on the meteorological data during 1959-2008 from five representative weather stations in the Urumqi River Basin and surrounding areas,the regional characteristics of temperature and precipitation in the basin featuring multi-climatic zones were studied by means of some methods including wavelet analysis.As was shown in the results,the temperature in the whole Urumqi River Basin demonstrated a significant upward trend.The temperature increase particularly in autumn and winter made the greatest contribution to the marked ascent.The interdecadal temperature in the basin showed a tendency to decline before the period during 1970s-1980s while it was on the rise after 1990s on the whole.The most concentrated period of temperature mutations was in the late 1990s.At the same time,the precipitation also showed an escalating trend,which experienced a stage of unanimous upward trend after 1990s.The most concentrated period of precipitation mutations was in the early 1990s.

Spatial Characteristics of Temperature Indices of Climate Change in China

Based on the temperature indices established by expert group on the detection,monitoring and indices of climate change,spatial characteristics of temperature indices from 278 meteorological stations in China during 1961-2008 were studied.The results showed that day number of freezing point went down gradually from northwest to southeast,as well as the most regions of China.Day number of summer was mostly over 50 d in China and over 100 d in Eastern China except for the most part of Northeast China,while there was an increase trend in the most regions of China.Growth period was generally above 150 d in China and increased with the decrease of latitude from north to south,while the trend coefficient of growth period in 236 stations was positive.

CHANGE OF CLIMATE AND ITS INFLUENCE ON THE CROPPING SYSTEM IN CHINA

Tne global change of climate and its influence on the cropping system in China have been investigated in this paper.It is found that the temperature was increased during the last decade and the precipitation decreased in northern China and increased in southern China during the last 30 years.The sea level has been rising by about 21—26 cm in the coastal areas south of 30°N in China during the last 100 years. The most of results as simulated by the general circulation models(GCMs)show that the temperature increase would amount to about 2°—4°C in the most parts of China and precipitation and soil moisture might be decreased in northern China and increased in sourthern China due to doubling of carbon dioxide(CO_2). The effects of doubled CO_2 on growth period and climatic yield capability in China have been estimated roughly.It is shown that the regions of the growth period in China would be moved northward about five degrees latitude and the climatic yield capability might be increased by about 10％ in the most parts of China.

The Role of Hydropower in Climate Change Mitigation and Adaptation： A Review

Hydropower is a clean,renewable,and environmentally friendly source of energy.It produces 3930(TW·h)·a–1,and yields 16% of the world's generated electricity and about 78% of renewable electricity generation(in 2015).Hydropower and climate change show a double relationship.On the one hand,as an important renewable energy resource,hydropower contributes significantly to the avoidance of greenhouse gas(GHG) emissions and to the mitigation of global warming.On the other hand,climate change is likely to alter river discharge,impacting water availability and hydropower generation.Hydropower contributes significantly to the reduction of GHG emissions and to energy supply security.Compared with conventional coal power plants,hydropower prevents the emission of about 3 GT CO2 per year,which represents about 9% of global annual CO2 emissions.Hydropower projects may also have an enabling role beyond the electricity sector,as a financing instrument for multipurpose reservoirs and as an adaptive measure regarding the impacts of climate change on water resources,because regulated basins with large reservoir capacities are more resilient to water resource changes,less vulnerable to climate change,and act as a storage buffer against climate change.At the global level,the overall impact of climate change on existing hydropower generation may be expected to be small,or even slightly positive.However,there is the possibility of substantial variations across regions and even within countries.In conclusion,the general verdict on hydropower is that it is a cheap and mature technology that contributes significantly to climate change mitigation,and could play an important role in the climate change adaptation of water resource availability.However,careful attention is necessary to mitigate the substantial environmental and social costs.Roughly more than a terawatt of capacity could be added in upcoming decades.

Impact of Climate Change and Grazing on Temperate Steppe

Ecosystem of eastern Eurasian steppe is facing more and more challenges of global issues such as climate change, food and ecological security and human excessive utilization since the 21st century. Facing on the increasingly prominent international issues, it is very essential for relevant countries, international organizations and domestic counterparts to enhance systematic and mutual cooperation and exchanges to carry out scientific research and develop protection practice on the Eurasian steppe.

Climatic change in Western North America during the last 15,000 years:The role of changes in the relative strengths of air masses in producing the changing climates

In the Cordillera of western North America, the influence of the Pacific Interdecadal Oscillation only affects coastal areas west of the Coast Range and the lowlands of western and southern Alaska. The rest of the area is subject to a climate controlled by the relative strengths of three distinct air masses, viz., the cold cA/cP air that is dominant in winter, the mP air bringing cool moist air over the mountains throughout the year, and the dry hot cT air from the deserts of the southwestern United States. The Arctic Front marks the boundary between the cA/cP air mass and the other two. Changes in the relative strengths of these air masses appear to explain the climatic changes documented throughout the region. Thus, in the last 30 years, the average position of the Arctic Front has moved north from about 53°N to 58°N, causing the warming in northern British Columbia and cooling south of Calgary, Alberta. This concept of changing positions of the air masses also appears to explain the mechanism behind the past climatic changes in this region. During the last Neoglacial event （c.1400-1900 A.D.）, it appears that the cA/cP air mass had strengthened enough to push the Arctic Front south of the 49th parallel. Incursions of mP air increased with localized areas of short-term heavy snowfalls resulting in small-scale advances of glaciers in these regions. This accounts for the variability in timing and extent of these glacial advances, while the resulting increased Chinook activity produced the development of a sand sea between Medicine Hat and Regina on the southern Prairies. The cT air mass was relatively weak, permitting these changes. During the maximum of the Altithermal/Hysithermal warm event （6,000 years B.P.）, the Arctic Front had retreated into the southern Yukon Territory as the cT air mass became stronger. The mP air could not move inland as easily, resulting in drier climates across the region. Prairie plants mi- grated into the southern Yukon Territory, and land snails from the eastern United States were able to migrate up the Saskatchewan River system as far as Lake Louise, Alberta. On the southern Prairies, the many small sloughs and lakes dried up. During the maximum of the Late Wisconsin Glacial event （15,000 years B.P.）, the Arctic Front had moved south to the vicinity of 30°N, while there had been a southward movement of the Zone of Intertropical Convergence from the equator to about 10°S. The mP air was also very strong and dumped enormous quantities of snow in the glaciated Canadian Cordillera, but it does not appear to have moved south any distance into the northern United States, witness the limited glaciation and widespread permafrost that developed there. Instead, there is evidence for buffering of the climatic changes in the closed basins in the northern Cordillera of the contiguous United States. The source of the cT air mass had moved south into the northern part of South America, permitting an exchange of savannah biota between the two continents. An extensive area of white dune sands inundated both savannah and forest along the inland hills in Guyana. This parallels the massive changes in African climatology during the last Ice Age （Fairbridge, 1964）. If these changes occurred each time there was a major glaciation in the Northern Hemisphere, this would explain the movement of biota from all terrestrial environments between the two American continents in the last 2 million years. A similar northward movement of climatic belts occurred in South America, with the cA air from Antarctica expanding northwards into southern Argentina and Chili. However paucity of data and the potential effects of El Ni o and the Southern Oscillation make it difficult toprovide details of the changes there in the present state of knowledge. This technique of studying the mechanisms of present-day climatic changes and applying the results to past climatic events has considerable potential for elucidating past climatic changes elsewhere in continental regions. This may prove particularly valuable in studying the Siberian anticyclone that is the main cause of the distribution of permafrost, but this will need international cooperation to be successful.

Preface to the Special Issue “Unified Perspective of Climate Variability and Change”

Forty years ago, Klaus Wyrtki （1975） of University of Hawaii discovered that E1 Nifio warming off South America is not a result of local wind change but a response to the relaxed equatorial trade winds some 10 000 km away near the international dateline. The Kelvin wave mechanism was quickly verified from wind-forced ocean model simulations. Consequent develop- ments show that the dance between the fast-reacting atmosphere and slow-evolving ocean sets the pace of E1 Nifio-Southern Oscillation （ENSO; Philander, 1990）. The concept of ocean-atmosphere interaction has revolutionized our view of the climate system and led to operational climate prediction.

The Potential Scenarios of the Impacts of Climate Change on Egyptian Resources and Agricultural Plant Production

The emissions of greenhouse gasses in Egypt are about 0.58% of the total emissions of the world in the year 2015, although Egypt is one of the countries most affected by the impacts of climate change. By assessment and analysis of the expected economic impacts of climate change by the year 2030, the Egyptian cultivated area will be reduced to about 0.949 million acres, equal to about 8.22% of the Egyptian cultivated area compared with the case of no sinking part of the Delta land, thus reducing crop area in Egypt to about 1.406 million acres, approximately to about 6.25% of crop area compared with the case of no sinking part of the Delta land, in addition to surplus in the Egyptian balance water to about 2.48 billion m3. In this case value of the Egyptian agriculture production will decrease by about 6.19 billion dollars, equal to about 6.19% compared with presumably no sinking of the Delta land. In the case of sinking 15% of Delta lands, with the change of the productivity and water consumption of most crops, the result will be a reduction in the cultivated area to about 0.94 million acres. In addition to decreasing the Egyptian crop area to about 1.39 million acres, with a deficit in the Egyptian balance water to about 4.74 billion m3 compared to the case of no sinking part of the Delta land, the cultivated area will decrease to about 8.17%, and the crop area will decrease 6.18%. Also, the value of the Egyptian agriculture production will decrease by about 12.51%. While compared to sinking part of the Delta land to about 15% of the total Delta area without the other impacts of climate change, the cultivated area will increase by about 0.06%;the crop area will increase by about 0.08%;also, the value of the Egyptian agriculture production will decrease by about 5.57%.

Systematic Synthesis of Impacts of Climate Change on China's Crop Production System

Global climate change is real and already taking place. The most recent Fifth Assessment Report of the Intergov- ernmental Panel on Climate Change （IPCC AR5） stated that global land and ocean surface temperature increased by 0.85℃ over the period of 1880 to 2012 （IPCC Climate Change 2013）. China is among the most affected countries by global climate change.

About A New Complex Method of Climates Reconstruction and Forecasting of Climate Changes in the Future

This paper deals with a new integrated method of reconstruction and forecasting of climatic changes in future. The method is based on proxy data pollen-spore analysis method, 14C analysis method, nowadays meteorological data, and data about of solar activity expressed in numbers of W （Wolf）. Here we present the results of investigation of sediments of the 2nd Fomich River terrace, Taymyr Peninsula, Russia. The formation of the peat bog started 10500 ± 140 years BP and continued during the entire Holocene. The pollen analysis of the sediment samples of the 2nd Fomich River terrace and the analysis of surface samples from a larch forest, typical of this region, reveals two phytochrones： both climatically preconditioned--tundra phytochrone （I1-4） and forest phytochrone （Ⅱ1-4）. The techniques of reconstruction and forecasting of basic elements of climate are presented and discussed in details.

Reality of Climate Change

AS predicted,U.S.President Donald Trump kept his campaign promise and pul ed out of the Paris Agreement on climate change on June 1,in line with his"America First"policy.The global agreement,adopted by the 196 parties of the United Nations Framework Convention on Climate Change at the 21st Session of the Conference of the Parties,is committed to cut greenhouse gas emissions and put the brakes on global warming.

The Interdecadal Changes of South Pacific Sea Surface Temperature in the Mid-1990s and Their Connections with ENSO

The characteristic changes of South Pacific sea surface temperature anomalies （SSTAs） for the period January 1979 to December 2011, during which the 1990s Pacific pan-decadal variability （PDV） interdecadal regime shifts occurred, were examined. Empirical Orthogonal Function （EOF） analysis was applied to the monthly mean SSTA for two sub-periods： January 1979 to December 1994 （P 1） and January 1996 to December 2011 （P2）. Both the spatial and temporal features of the leading EOF mode for P1 and P2 showed a remarkable difference. The spatial structure of the leading EOF changed from a tripolar pattern for P 1 （EOF-P 1） to a dipole-like pattern for P2 （EOF-P2）. Besides, EOF-P 1 （EOF-P2） had significant spectral peaks at 4.6 yr （2.7 yr）. EOF-P2 not only had a closer association with E1 Nifio-Southern Oscillation （ENSO）, but also showed a faster response to ENSO than EOF-P1 based on their lead-lag relationships with ENSO. During the development of ENSO, the South Pacific SSTA associated with ENSO for both PI and P2 showed a significant eastward propagation. However, after the peak of ENSO, EOF-P1 showed a stronger persistence than EOF-P2, which still showed eastward propagation. The variability of the SSTA associated with the whole process of ENSO evolution during P1 and the SSTA associated with the development of ENSO during P2 support the existence of ocean-to-atmosphere forcing, but the SSTA associated with the decay of ENSO shows the phenomenon of atmosphere-to-ocean forcing.

REDEFINING ENSO EPISODES BASED ON CHANGED CLIMATE REFERENCES

Through studying changes in ENSO indices relative to change of climate reference from 1961~1990 to 1971~2000, the study generated new standards to define ENSO episodes and their intensities. Then according to the new climate references and new index standards, ENSO episodes and their intensities for the period 1951 -2003 have been classified. Finally, an analysis has been performed comparing the new characteristics with the old ones for ENSO period, peak values and intensities.

LOW FREQUENCY VARIABILITY OF INTERANNUAL CHANGE PATTERNS FOR GLOBAL MEAN TEMPERATURE DURING THE RECENT 100 YEARS

The TEEOF method that expands temporally is used to conduct a diagnostic study of the variation patterns of 1, 3, 6 and 10 years with regard to mean air temperature over the globe and Southern and Northern Hemispheres over the course of 100 years. The results show that the first mode of TEEOF takes up more than 50% in the total variance, with each of the first mode in the interannual oscillations generally standing for annually varying patterns which are related with climate and reflecting long-term tendency of change in air temperature. It is particularly true for the first mode on the 10-year scale, which shows an obvious ascending trend concerning the temperature in winter and consistently the primary component of time goes in a way that is very close to the sequence of actual temperature. Apart from the first mode of all time sections of TEEOF for the globe and the two hemispheres and the second mode of the 1-year TEEOF, interannual variation described by other characteristic vectors are showing various patterns, with corresponding primary components having relation with long-term variability of specific interannual quasi-periodic oscillation structures. A 2T test applied to the annual variation pattern shows that the abrupt changes for the Southern Hemisphere and the globe come closer to the result of a uni-element t test for mean temperature than those for the Northern Hemisphere do. It indicates that the 2Ttest, when carried out with patterns of multiple variables, seems more reasonable than the t test with single elements.

China's response to climate change issues after Paris Climate Change Conference

The Paris Climate Change Conference was successfully concluded with the Paris Agreement, which is a milestone for the world in collectively combating climate change. By participating in IPCC assessments and conducting national climate change assessments, China has been increasing its understanding of the issue. For the first time, China＇s top leader attended the Conference of the Parties, which indicates the acknowledgement of the rationality and necessity of climate change response by China at different levels. Moreover, this participation reflects China＇s commitment to including climate change in its ecology improvement program and pursuing a low-carbon society and economy. In order to ensure the success of the Paris Conference, China has contributed significantly. China＇s constructive participation in global governance shows that China is a responsible power. These principles such as the creation of a future of win-win cooperation with each country contributing to the best of its ability; a future of the rule of law, fairness, and justice; and a future of inclusiveness, mutual learning, and common development will serve as China＇s guidelines in its efforts to facilitate the implementation of the Paris Agreement and participate in the design of international systems.

The Characteristics of Changes in Sunshine Hours of Jimusi Region in Sanjiang Plain

Based on the data of sunshine hours from the four stations in Jiamusi region in Sanjiang Plain from 1961 to 2011, we analysed the changing tend and the abnormal year of sunshine hours in this region. The results showed that annual sunshine hours reduced extremely significantly in three stations of Jiamusi region in Sanjiang Plain in recent 50 years, especially in spring and winter, and the decrease of annual sunshine hours was the largest in the middle of Jiamusi region, followed by the west, while it was the smallest in the east. On the contrary, annual sunshine hours increased extremely significantly in Fuyuan in the northeast. Monthly sunshine hours of this area changed from 134.1 to 246.0 h, and the maximum data appeared in March, and the next was June, while the minimum one appeared in December. Total monthly sunshine hours reached the maximum in Tangyuan in the west, followed by middle Jiamusi and Fujin in the east, while the minimum appeared in Fuyuan in the northeast. Sunshine hours showed an increasing tendency only in July and August. From 2001 to 2011, annual sunshine hours showed a decreasing tendency in Jiamusi, while there was an obvious increase in Tangyuan, Fujin and Fuyuan; in the 20th century, annual average sunshine hours from the 1980s to 1990s decreased by 267.7 h compared with that from 1960s to 1970s. Among them, sunshine hours were the fewest in the 1990s. In recent 50 years, there was an abnormal increase in annual sunshine hours in Jiamusi in 1975 and 1982; while there were abnormal decreases in Tangyuan and Fujin in 1993, Fujin in 1995, and Fuyuan in 1982 and 1987.

The Influence of Weather and Climate Variability on Groundwater Quality in Zanzibar

Climate change and variability have been inducing a broad spectrum of impacts on the environment and natural resources including groundwater resources. The study aimed at assessing the influence of weather, climate variability, and changes on the quality of groundwater resources in Zanzibar. The study used the climate datasets including rainfall (RF), Maximum and Minimum Temperature (Tmax and Tmin), the records acquired from Tanzania Meteorological Authority (TMA) Zanzibar office for 30 (1989-2019) and 10 (2010-2019) years periods. Also, the Zanzibar Water Authority (ZAWA) monthly records of Total Dissolved Solids (TDS), Electrical Conductivity (EC), and Ground Water Temperature (GWT) were used. Interpolation techniques were used for controlling outliers and missing datasets. Indeed, correlation, trend, and time series analyses were used to show the relationship between climate and water quality parameters. However, simple statistical analyses including mean, percentage changes, and contributions to the annual and seasonal mean were calculated. Moreover, t and paired t-tests were used to show the significant changes in the mean of the variables for two defined periods of 2011-2015 and 2016-2020 at p ≤ 0.05. Results revealed that seasonal variability of groundwater quality from March to May (MAM) has shown a significant change in trends ranging from 0.1 to 2.8 mm/L/yr, 0.1 to 2.8 μS/cm/yr, and 0.1 to 2.0℃/yr for TDS, EC, and GWT, respectively. The changes in climate parameters were 0.1 to 2.4 mm/yr, 0.2 to 1.3℃/yr and 0.1 to 2.5℃/yr in RF, Tmax, and Tmin, respectively. From October to December (OND) changes in groundwater parameters ranged from 0.2 to 2.5 mm/L/yr 0.1 to 2.9 μS/cm/yr, and 0.1 to 2.1℃/yr for TDS, EC, and GWT, whereas RF, Tmax, and Tmin changed from 0.3 to 1.8 mm/yr, 0.2 to 1.9℃/yr and 0.2 to 2.0℃/yr, respectively. Moreover, the study has shown strong correlations between climate and water quality parameters in MAM and OND. Besides, the paired correlation has shown significant changes in all parameters except the rainfall. Conclusively, the study has shown a strong influence of climate variability on the quality of groundwater in Zanzibar, and calls for more studies to extrapolate these results throughout Tanzania.

Worrying about Climate Change

It is becoming clear that Climate Change is getting severe. It was reported that the improved ocean heat measurements have a rate of warming upwards from 4 to 5 Hiroshima bombs liberated heat per second or 388,800 per day. It was reported also that our climate has accumulated the equivalent of a total of more than 2.8 billion Hiroshima bombs’ worth of heat since 1998. Despite this global concern about the effect of global change on environment, it is believed that the problem is much more severe and with greater impact on all facets of life. The effect of Climate Change, especially with a 1℃increase in global temperature (from 14℃to 15℃) is equivalent to the heat liberated from explosion of about 300 million Hiroshima of atomic bomb. This is why this CoP 26 becomes more serious and had targeted year 2060 as a year of zero CO2 emission. This paper discusses the impact of climate change on ten sectors;water, water desalination, energy, renewable energy supply, health, society, agriculture, economy, industry, and built environment.

Incorporating shape constraints in generalized additive modelling of the height-diameter relationship for Norway spruce

Background： Measurements of tree heights and diameters are essential in forest assessment and modelling. Tree heights are used for estimating timber volume, site index and other important variables related to forest growth and yield, succession and carbon budget models. However, the diameter at breast height （dbh） can be more accurately obtained and at lower cost, than total tree height. Hence, generalized height-diameter （h-d） models that predict tree height from dbh, age and other covariates are needed. For a more flexible but biologically plausible estimation of covariate effects we use shape constrained generalized additive models as an extension of existing h-d model approaches. We use causal site parameters such as index of aridity to enhance the generality and causality of the models and to enable predictions under projected changeable climatic conditions. Methods： We develop unconstrained generalized additive models （GAM） and shape constrained generalized additive models （SCAM） for investigating the possible effects of tree-specific parameters such as tree age, relative diameter at breast height, and site-specific parameters such as index of aridity and sum of daily mean temperature during vegetation period, on the h-d relationship of forests in Lower Saxony, Germany. Results： Some of the derived effects, e.g. effects of age, index of aridity and sum of daily mean temperature have significantly non-linear pattern. The need for using SCAM results from the fact that some of the model effects show partially implausible patterns especially at the boundaries of data ranges. The derived model predicts monotonically increasing levels of tree height with increasing age and temperature sum and decreasing aridity and social rank of a tree within a stand, The definition of constraints leads only to marginal or minor decline in the model statistics like AIC An observed structured spatial trend in tree height is modelled via 2-dimensional surface fitting. Conclusions： We demonstrate that the SCAM approach allows optimal regression modelling flexibility similar to the standard GAM but with the additional possibility of defining specific constraints for the model effects. The longitudinal character of the model allows for tree height imputation for the current status of forests but also for future tree height prediction.

Transmission of climate change impacts from temperature change to grain harvests, famines and peasant uprisings in the historical China

Because of the complexity of social responses to climate change,as well as limitations of proxy data concerning interactions between climate change and human responses,the social impacts of past climate change and associated response mechanisms,thus,require further investigation.To shed light on the transmission of climate change impacts within historical Chinese society,we selected 30-year resolution sequences of temperature anomalies in eastern China and 10-year resolution sequences of grain harvest grades,famine indices,and frequencies of peasant uprisings in China over the past 2000 years.Using a food security perspective,we analyzed the impacts of temperature changes historically transmitted through Chinese production,population,and social subsystems,and differences in transmission characteristics between cold and warm units.Our results were as follows.(1)From 210 BC to 1910 AD,temperature changes in China were significantly positively correlated with grain harvest grades(correlation coefficient,0.338),and significantly negatively correlated with famine indices,and frequencies of peasant uprisings(correlation coefficients,-0.301 and-0.277,respectively).The correlation coefficients between famine indices and grain harvest grades or frequencies of peasant uprisings were very low.(2)There was a higher proportion of bumper or normal harvests(86.5%of the total decades),more moderate and mild famines(76%),and a lower proportion of peasant uprisings(33.3%)in the 30-year warm units.Conversely,there was a higher proportion of poor or normal harvests(70.7%),a greater proportion of moderate and severe famines(77.6%),and more peasant uprisings(51.7%)in the 30-year cold units.(3)Of the 23 main transmission pathways extending from temperature change to the social subsystem,13 occurred in cold units,of which 7 had an endpoint of peasant uprisings,and 10 occurred in warm units of which 3 had an endpoint of peasant uprisings.The main transmission pathways that were more likely to be associated with the impacts of temperature change were:Cold→poor harvests→severe famines→more uprisings;cold→poor harvests→moderate famines→more uprisings;warm→bumper harvests→mild famines→no uprisings;warm→bumper harvests→moderate harvests→no uprisings;warm→normal harvests→mild famines→no uprisings;and warm→normal harvests→moderate famines→no uprisings.(4)The transmission of the impacts of temperature change was a complex process.Within this process,famine was most prone to being modulated by human society.In the transmission pathways from the production to the social subsystem,there was a stepwise decrease in the occurrence rate of decades that were probably affected by climate change.In all cold units,10.4%of decades ending in more uprisings were most likely to be associated with the impacts of temperature change.In all warm units,47.9%of decades ending in no uprisings were most likely to be associated with the impacts of temperature change.This research can contribute a better understanding on the past interaction mechanisms and processes within the human-climate-ecosystem complex,as well as a better response to the impacts of the ongoing climate change.