March, 2017 Journal of Resources and Ecology Vol. 8 No.2 J. Resour. Ecol. 2017 8(2) 141-147 DOI: 10.5814/j.issn.1674-764x.2017.02.004 www.jorae.cn Land Aridization in the Context of Global Warming a Case Study of Transbaikalia Anatoly I. KULIKOV 1,*, Bair Z. TSYDYPOV 2, Bator V. SODNOMOV 2, Ayur B. GYNINOVA 1, WANG Juanle 3 1. Institute of General and Experimental Biology, Siberian Branch, Russian Academy of Sciences, Ulan-Ude 670047, Russia; 2. Baikal Institute of Nature Management, Siberian Branch, Russian Academy of Sciences, Ulan-Ude 670047, Russia; 3. State Key Lab of Resource and Environmental Information System, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Abstract: An increase in the extremality of natural processes is a consequence of warming, aridization, and desertification. The authors consider the processes of warming, aridization, and desertification to be the parts of a single system and major destabilizing factors of ecological balance. Destabilization is expressed in the growth of natural processes extremality. Ecosystems of Transbaikalia were once characterized by a different natural contrast and amplitude. Warming, aridization and desertification have led to an increase of environmental regimes tensions. This is demonstrated quantitatively by the root-mean-square difference of atmospheric and soil parameters. Quantitative indicators of aridization are estimated using Walter-Gossen climate charts. Permafrost zone response information to the long-term warming is provided as well. Key words: climate change; warming; aridization; desertification; extremality; drought 1 Introduction Post-industrial globalizing society is threatened by global warming. This fact is articulated in the United Nations Framework Convention on Climate Change (1992), the first legal document of which was the famous Kyoto Protocol, issued in 1997. Russia ratified the protocol in 2004. Today the problem of climate change is being intensively studied under the coordination of the Intergovernmental Group of Experts on Climate Change and others. Climate warming at the feedback loop leads to ecosystem reactions such as aridization and desertification. The International Convention to Combat Desertification (CCD 1994) was signed by 170 countries; the Russian Federation signed this convention in 2003. The convention defines desertification as land degradation in arid, semiarid and dry subhumid areas as the result of different factors, including climate change and human activity. Arid, semiarid and dry subhumid lands include the regions (alongside polar and sub-polar regions), where the ratio of annual precipitation to potential evapotranspiration ranges from 0.05 to 0.65. The steppe region of Transbaikalia is one of the regions experiencing drought and desertification. Today the components of warming, aridization and desertification (WAD system) are closely linked together by direct and inverse relationships (Fig. 1). The emergence of a new system of warming, aridization, desertification (WAD system) has resulted in a further disturbance of the ecological balance, environmental degradation Fig.1 Relationships in the WAD system Received: 2016-04-21 Accepted: 2017-01-20 Foundation: These investigations were partially supported by the Russian Geographical Society (grant No. 13-05-41378) *Corresponding author: Anatoly I. KULIKOV, E-mail: kul-an52@mail.ru Citation: Anatoly I. KULIKOV, Bair Z. TSYDYPOV, Bator V. SODNOMOV, et al. 2017. Land aridization in the context of global warming a case study of Transbaikalia. Journal of Resources and Ecology. 8(2): 141-147.
142 Journal of Resources and Ecology Vol. 8 No. 2, 2017 and an increase in the number of natural, man-made and natural-anthropogenic disasters. Since the beginning of the 21 st century the number of disasters of natural origin has increased more than 3 times in comparison with the 1960s. This increase has been accompanied by a large loss of life and material (Osipov 2007). At the same time the rate of increase of the number of victims of natural disasters is 8.6%, and the economic losses 10.4% per year (Natural 2003). Arid lands and deserts existed in earlier climate eras, but global warming is a cause of ecosystem responses which come to fruition in the phenomena of desertification and aridization. Thus, global warming leads to the emergence of new relationships or the exacerbation of pre-existing relationships. 2 Materials and methods The research territory is shown in Fig. 2. This evaluation of climate change is carried out using file materials from hydrometeostations in Transbaikalia. Also, Internet resources and our field research data are used. In particular, the results were derived both from stationary and route studies of temperature and humidity of the surface layer of the atmosphere, and of the soil at a depth of 0.2-0.5 m in steps up to the top of the roof thawing permafrost. For recent years, a complex of long-term automatic measurement of the vertical profile of temperature and humidity in the air and soil is applied. Trend changes were approximated by a linear function y=ax+b, where a is an angular coefficient that shows the rate of change. The variability of the parameters is evaluated by the coefficient of variation and root-mean- square difference calculation. The accuracy of the sample differences is estimated by the Student s t-test. The parameters of aridization are determined using Walter-Gossen charts. The cryological measurements were held together with a heat flow survey (isotherms fixation is 0 C) using the drilling method in the field and visually observing the ice schliere crystals in the soil cores and palpation. 3 Results and discussion Global warming is confirmed by long-term data from the network of stations of the World Meteorological Organization and from national meteorological networks. From 1860 to 1998 global temperatures from the Arctic, the taiga, dry steppes, high mountains, the tropics and the Dry Valleys of Antarctica have risen by about 0.8 С (Watson et al. 2001). In Russia, since the beginning of the 20 th century the temperature increase has been calculated at 0.9 (Gruza et al. 2006) to 1.1 C (Anisimov et al. 2007). In some areas of the Russian North in the past 30-35 years, the air temperature has increased by 1.0 1.5 C. The greatest changes in climate are in temperate latitudes. In the last 30 35 years air temperature has increased by 1.6 2.1 C (Mel'nikov et al. 2007; Perl shtein et al. 2006). In Russia, temperatures are increasing at a more pronounced rate than elsewhere in the world; this is especially the case in the territory of Transbaikalia (Kulikov et al. 2008) where temperatures have increased about 2.5 C. Other researchers emphasize the accelerated warming in Cisbaikalia and Transbaikalia as well (Gruza et al. 2004). The changes of thermal regime and ice conditions of Lake Baikal also indicate a warming process (Anokhin et al. 2006). It is noteworthy that in the last ten years the average annual temperature in Transbaikalia has crossed the zero line. Today the average annual temperature is a positive number. Earlier, this was the case only occasionally. In Ulan-Ude the air temperature increase rate is equal to 0.23 C/10 years. Since the 1970s, mean annual temperature has increased by 0.36 C in 10 years. Warming is happening at a rate of 0.18 C in Novoselenginsk and 0.16 C in Kyakhta Fig.2 The territory where research was undertaken
Anatoly I. KULIKOV, et al.: Land aridization in the context of global warming--a case study of Transbaikalia 143 over 10 years. A phenomenon of extremality is typical for the steppe landscapes, i.e. high amplitude, contrasting effect, relative frequency, and arrhythmia of natural processes. All of these factors can be quantified by one indicator root-meansquare deviation (RMS) and derived from its variation coefficient. Fluctuations of the precipitation amount from year to year are very high. The difference between individual years can be as great as 100 150 mm. In Ulan-Ude the points of extremum are 413.3 mm (1959) and 109.6 mm (1989), and the average amplitude is 303.7 mm. Variability of precipitation increases over the course of time, i.e. extremality of conditions based on this indicator increases. Thus, during the years 1935 1942, RMS of annual precipitation amount was equal to ±32.2 mm. But now the deviation from the climatic norm has become sharper and RMS is ±65 83 mm; that is, long-term mean deviations of the sum (256 mm) have increased from 13% to 25% 32 % (Fig. 3). Sharp differences between atmospheric moisture in different years imply an increase of the probability of catastrophic events. An extension of irrigation reclamation is needed to reduce agricultural industry dependence on weather. To check extremality increase, root-mean-square deviation is compared for two time periods in the range of 50 60 N from the east (Klyuchi, Ust-Kamchatsky District of Kamchatka Krai, Russia, E160.8) to the west (Uzhhorod, Zakarpattia Oblast, Ukraine, E22.3) (Fig. 3). This area of the Central Asian steppes to the west is almost the same as the Voeikov climate axis. The wind-separating Voeikov axis begins from the steppe and desert expanses of Central Asia, where powerful high pressure fields are formed in the winter. From Central Asia the Asian anticyclone extends westward across the Barabinsk-Kulundinsky steppe to the northern Caspian and the Volga region, and further to the Don steppes and finally to the Danubian Pashto. Thus, the Voeikov axis is formed along the line of Kyakhta Kyzyl (geographic center of Asia) Uralsk Saratov Kharkiv Chisinau, and the axis is strictly controlled by the Asian anticyclone. For the east-west axis, RMS difference of average annual air temperature is above zero in most cases. The time period from 1979 2007 is characterized by greater volatility than the period from 1961 1990 (Fig. 4). Thus global warming causes weakening of the temperature stability conditions. It must be stressed that in the west RMS value of the difference increases slightly, meaning that thermal stability conditions decrease. The difference between the RMS of air temperature for two time intervals, which is calculated for the two main seasons (winter, summer), shows a statistically significant difference of the compared series t f = 5.4 > t 01 = 3.5. That is, t-student statistics exceed t-table at the level of importance P 0.1 %. Because RMS of air temperature in the winter is lower than in the summer, we can say that summers are a source of instability of heat supply. Extremality of arid ecosystems is also reflected in increased values for the variability of fundamental characteristics like soil moisture in the 0.0 0.5 m layer, and temperature at a depth of 0.2 m (Fig. 5). The data on frozen soils is given for comparison. Frozen soils are characterized by high inertia. In the period from Fig.4 Difference between average annual RMS of the air temperature in the periods of 1979 2007 and 1961 1990 Fig.3 Dynamics of the amounts of precipitation by climate circle and an increase in volatility of atmospheric moisture. Blue the long-term average precipitation for climate circle, red the long-term average rainfall for the entire period, cyan range of the RMS change, and RMS values for climate circle Fig.5 Extremality of steppes estimated by mathematicalstatistical coefficient of the variation of long-term (1968-2003) series of hydro-(1) and thermal (2) regimes of soil. The variability of agrobiocenoses productivity (3). 1 indicators of sandy loam soils of dry steppe, 2 indicators of clay-loam frozen soil of forest steppe
144 Journal of Resources and Ecology Vol. 8 No. 2, 2017 July to September the variability of temperature and moisture is 20-30% higher for extreme landscape soils than for heavy permafrost soils. Therefore, in a dry steppe the biological productivity of natural and cultural phytocoenosis is characterized by considerable instability for different years. The extremality of steppes is further exacerbated by aridization in modern times. Aridization is a process in which a landscape evolves in the direction of aridity increasing as a result of potential evaporation increase under precipitation. Aridization as a result of warming is supported by a positive feedback. Warming implies an increase in cloudless days and higher radiation heating of the surface. Warming causes desiccation of the active surface, and this results in further heating of the surface. The reduction of precipitation, the periodicity of effective rainfall (more than 5 mm/day) and increase of the periodicityhat of extreme precipitation (especially droughts) are external regulators of positive feedback. An increase of the active temperature amount while total precipitation remains unchanged is characteristic of the aridization in Transbaikalia. The rate of increase of the active temperature amount is 114 C over 10 years, with an average annual norm of 1897 C. Over a period of more than 100 years the active temperature amount has increased by 370 450 C. From G.T. Selyaninov s empirical formula, it follows that if the sum of active temperatures Σt 10 C = 10, then volatility (Is) is equal to t 10 C Is 1 mm. 10 In Transbaikalia the evaporation potential during the most recent 100 year period has increased by 37 45 mm. This suggests that the climatic norm for irrigation must be increased by 370 450 m 3 /ha. This finding is significant as it allows for agromeliorative content that addresses global changes. This increase of the climatic norm for irrigation is very significant when consideration is given to the fact that, at the present time in Buryatia, 151257 hectares of land are irrigated, and the potential reclamation fund of land is 2,306,000 hectares. With the amount of the temperature increase exceeding 10 С, the period of time for these temperatures is greatly extended. There has been a change from a short growing period (90 120 days) for vegetation to a medium period (121 150 days). The length of the summer season has increased by 12 days; the winter has decreased by 15 days. The duration of the period between the dates at the transition through the 0 С grade is increasing at the rate of 5.7 days per 10 years. One of the main features of land aridization is drought. Drought is a bio and hydrometeorological phenomenon that amounts to a breakdown of the correspondence between the influx of water to the plant and its consumption. The appearance of drought is due to circulation processes in the atmosphere (anticyclone). It is a consequence of prolonged absence of rain (or a substantial reduction), heightened air temperatures and high winds (Gringof et al. 2005). There are three types of droughts: atmospheric, soil and atmosphere-soil (total). The atmosphere-soil drought is the greatest threat for farming. In the region of Transbaikalia, decreased humidity and increased wind speed are conditions for drought and aridization (Fig. 6). The rate of decline of relative humidity in Novoselenginsk has been equal to 0.33% per year over a ten year period, and the wind speed has risen at 0.12 m/s a 10 years. The Baikal Institute of Nature Management SB RAS identified the areas of arid lands (http://www.sbras.ru/win/ sbras/rep/2000/nz/nz2.html) (Fig. 7). The identification was based on an aridity index (P/PET) the ratio of precipitation to potential evapotranspiration (evaporation) over the past 80-90 years. This figure in Russia is known as the Vysotsky-Ivanov moisturizing factor, established in the early twentieth century. Walter-Gossen climate diagrams are constructed for quantitative assessment of land aridization (Fig. 8). Aridization of the steppe is increasing. Especially in recent decades, the intensity of droughts is increasing. Autumn droughts, which were not recorded previously, have been observed in recent years. This can be seen on the climate diagrams. Apparently for this reason, autumn fires have become frequent in the Transbaikalia forests. Currently, only in the spring period droughts are observed for 29 days, Fig.6 Long-term dynamics with trends: A relative humidity and B average wind speed, during the period April to May. Meteorological station Novoselenginsk
Anatoly I. KULIKOV, et al.: Land aridization in the context of global warming--a case study of Transbaikalia 145 Fig.7 Areas of land aridization in Transbaikalia. Arid climate zones: 1 semiarid (0.2<P/PET<0.5), 2 dry subhumid (0.5<P/PET<0.65), 3 semiarid subhumid (0.65<P/PET<0.75), 4 moist subhumid and humid (0.75<P/PET) Fig.8 Walter-Gossen Climate diagrams for the meteorological Khorinsk station. Note: 1 monthly mean air temperature, 2 precipitation at the ratio of 20 mm = 10 С, 3 precipitation at the ratio 30 mm=10 С, 4 moderate drought period, 5 extreme drought period, 6 period with the temperature above 5 C, 7 period with the temperature above 10 C
146 Journal of Resources and Ecology Vol. 8 No. 2, 2017 and in the autumn period for 37 days (note that the dry season lasts for 66 days). The number of effective temperature days has increased up to no less than 20 days, compared to 1930 1960. This is shown on the climate diagrams (Fig. 8). Permafrost is very responsive to changes in thermodynamic conditions of the Earth, because it was formed by and its operation is dependent on the radiation-heat balance. Permafrost reacts to warming reduction in area, temperature increases and the depth of seasonal thawing (Fig. 9). In Transbaikalia the depth of seasonal thawing in the period 1909 2008 increased on open uplands to 1 1.6 m (curves 2, 5, 7 9) and in forests to approximately 0.2 0.25 m (curves 3, 6), but in closed, poorly drained depressions change was zero or negative (curves 1 and 4) (Kulikov et al. 2009; Kulikov et al. 2008). Temperature increases at the check point depth (1.6 m) was equal to 0.05 0.08 C/year, and at a number of points, the average annual temperature crossed the zero line, i.e. neoplasm of frost is practically impossible. Among the regions, the Transbaikalia is distinguished by the forced thawing permafrost. When warming reaches the point that the average annual air temperature has become positive, the conditions needed to preserve permafrost do not exist. In the long term, areas of permafrost degradation will further expand. Thus, increase of permafrost temperature is expected to be approximately 1.5 2.0 С, and the depth of seasonal thawing is 25 50%. Model calculations by V.A. Kudryavtsev (General 1978) found that with constant thermal properties (λ = 4.48 kj/m h С thermal conductivity, C = 2095 kj/m 3 С thermal capacity, Q = 98884 kj/m 3 heat input on the soil thawing) and constant amplitude of the temperature rise to 0 С, the depth of thawing will increase up to 3.8 m. Today, Fig.9 Increase of the power of the activity layer in the different permafrost geosystems the layer subject to seasonal thawing has become so that during the cold period complete refreezing is not possible. The upper part of permafrost thickness melts permanently and permafrost is separated from the surface and becomes a relic form; frozen soils become seasonally frozen soil (Table. 1). The principal problems of warming, aridization and desertification and also their solutions are discussed in our monograph (Kulikov et al. 2014). 4 Conclusions Climate warming is occurring more rapidly in the Transbaikalia region than elsewhere in Russia and the world. Aridization and desertification are considered to be among regressive ecosystem responses. The two are closely related, allowing the selection of a special system Warming Aridization Desertification. The accelerated warming in Transbaikalia is expressed in high values of regression coefficients of linear trends of mean annual air temperature, with data take from a number of meteorological stations in the region. For quantitative estimation of climate extremality, we used a simple but objective indicator: the standard deviation. At the present time, compared to the 1930s of the last century, the standard deviation has increased 2 2.5 times at unchanged annual amounts of precipitation. The probability of catastrophic events has increased proportionally with the increase of standard deviation. Along with global warming, the stability of temperature conditions is decreasing, and to a greater degree during the summer period. Because soil moisture, temperatures and bio-productivity vary greatly in these areas, steppe landscapes should be considered as extreme landscapes. Steppe extremeness is further exacerbated today by aridization. An increase of the amount of active temperatures and a subsequent increase of evaporating capacity are at the heart of aridization. The duration of the drought period in the steppe landscapes is defined in the climate diagrams obtained from the data. The duration of drought periods are increasing over the time. Autumn droughts have been observed today, though 50 years ago in the 1960s autumn droughts were rare. Currently, autumn droughts happen regularly. Apparently, autumn fires are associated with these droughts. Desertification has covered large areas of agricultural lands in the region. Table 1 Forecasting changes of the seasonal thawing depth of soil under climate warming Physical temperature range on the soil level (А о, С) 15* * Current conditions Average annual soil temperature (t o, C) The depth of soil thawing (h, m) 3* 2.6* 2 3.0 1 3.4 0 3.8
Anatoly I. KULIKOV, et al.: Land aridization in the context of global warming--a case study of Transbaikalia 147 Widespread long-term permafrost reacts to warming by the reduction of permafrost area, an increase of temperature and an increase of thawing capacity. The dynamics of thawing have been studied in different geosystems over the past century. References Anisimov O A, V A Lobanov, S A Reneva. 2007. Analysis of changes in air temperature in Russia and empirical forecast for the first quarter of the 21st century. Russian Meteorology and Hydrology, 32(10): 620 626. Anokhin Yu A, L I Boltneva, L T Myach. 2006. About assess of the possible impacts of climate change on the ecosystem of Lake Baikal. Proc. rep. II All-Russia. Conf. The scientific aspects of environmental problems in Russia. Moscow. (in Russian) CCD: United Nations Convention to combat desertification in those countries experiencing serious drought and desertification, particularly in Africa. 1994. Geneva. Switzerland, 78. Gringof I D, A D Pasechnyuk. 2005. Agrometeorology and agrometeorological observations. Saint-Petersburg, 552. (in Russian) Gruza G V, E Ya Ran kova, L N Aristova, et al. 2006. Uncertainties in some scenario climatic forecasts of air temperature and precipitation for Russia. Russian Meteorology and Hydrology, 10: 5 23. (in Russian) Gruza G V, E Ya Ran'kova. 2004. Detection of climate change: the state, variability and extreme of climate). Proceeding of World Conference of climate change. Moscow, 101 111. (in Russian) Kulikov A I, M A Kulikov, I I Smirnova. 2009. The depth of thawing of the soil in situation of climate change. Herald of the Buryat State Agricultural Academy, 1(14): 121 126. (in Russian) Kulikov A I, M A Kulikov, I I Smirnova. 2008. Thermal state of the effective layer in permafrost in the Baikal region in the context of global warming. Climate Change in Central Asia: the socio-economic and environmental impacts. Proceedings of International Conference. Chita, 171 178. (in Russian) Kulikov A I, A Ts Mangataev, M N Sordonova, et al. 2014. Melioration of light soils in the context of current challenges. Ulan-Ude: Publishing House of SB RAS BSC, 487. (in Russian) Mel'nikov V P, A V Pavlov, G V Malkova. 2007. Geocryological after-effects of modern global climate change. Geography and Natural Resources, 3: 19 27. (in Russian) General permafrostology. 1978. Moscow: Moscow State University, 464. (in Russian) Osipov V I. 2007. Assessment and management of natural risks (state of the problem). Environmental Geoscience, 3: 201 211. (in Russian) Perl'shtein G Z, A V Pavlov, A A Buiskikh. 2006. Changes in the permafrost zone upon the modern climate warming. Environmental Geoscience, 4: 305 312. (in Russian) Natural hazards of Russia. Assessment and management of natural risks. 2003. Moscow: KRUK, 6: 316. (in Russian) Watson R T and the Core Writing Team. 2001. Climate Change 2001: Synthesis Report. Summary for Policymakers. A Report of the Intergovernmental Panel on Climate Change. IPCC Secretariat, c/o World Meteorological Organization, Geneva. Switzerland, 151. Anatoly I. KULIKOV 1, Bair Z. TSYDYPOV 2, Bator V. SODNOMOV 2, Ayur B. GYNINOVA 1, 王卷乐 3 1. 俄罗斯科学院西伯利亚分院实验生物学研究所, 乌兰乌德 670047 俄罗斯 ; 2. 俄罗斯科学院西伯利亚分院贝加尔湖自然管理研究所, 乌兰乌德 670047 俄罗斯 ; 3. 中国科学院地理科学与资源研究所, 资源与环境信息系统国家重点实验室, 北京 100101 摘要 : 气候变暖 干旱化和荒漠化导致了自然过程极端事件的增加 本文认为气候变暖 干旱化和荒漠化过程作为整体系统的组成部分, 是生态平衡的重大不稳定因素 自然过程极值的增长是生态系统失衡的一种表现形式 气候变暖 干旱化和荒漠化加剧了跨贝加尔地区生态系统的失衡及当地紧张的环境局势 本文采用大气和土壤参数的均方根差及 Walter-Gossen 气候图表定量估计了跨贝加尔地区的干旱状态, 并提供了永久冻土区对长期变暖响应的有关信息 关键词 : 气候变化 ; 气候变暖 ; 干旱化 ; 荒漠化 ; 极值 ; 旱情