Acta Ecologica Sinica 32 (2012) 74–88
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Emergy-based environmental accounting: Evaluation of Inner Mongolia Autonomous Region L.P. Zhu a, H.T. Li a,b,c,⇑, J. Bouldin d, R. John b, M.C. Yan a, T. Liang a a
Institute of Geographic Sciences and Natural Resources Research, The Chinese Academy of Sciences, Beijing 100101, China Department of Environmental Sciences, The University of Toledo, Toledo, OH 43606, USA c International Ecological Research Center, Zhejiang University of Agriculture and Forestry, Hangzhou, Zhejiang 311300, China d Department of Plant Sciences, University of California, One Shields Ave., Davis, CA 95616, USA b
a r t i c l e
i n f o
Article history: Received 10 June 2011 Revised 29 September 2011 Accepted 15 December 2011
Keywords: Emergy Inner Mongolia Autonomous Region Sustainability
a b s t r a c t An integrated environmental accounting of the Inner Mongolia Autonomous Region (IMAR) is presented, based on an emergy analysis using data on environmental and economic inputs and outputs within and without IMAR from 1987 to 2007. This includes an analysis of resource and economic structure and trade status. Using these metrics, IMAR is compared with other Chinese regions, as well as the nation as a whole, with respect to the performance and stainability of their respective ecological-economic systems. Results show that more than 85% of the emergy in IMAR was derived from home region sources, indicating a strong capacity for self-sufficiency, even if this amount as a percentage of the total declined from about 93 to 87 percent over the 20 year period. These results also show, that the value of the emergybased stainability index (1.86 in 2007) indicates that IMAR is a sustainable system over medium length time periods. However, the imbalance of trade, the over-dependence on nonrenewable resources, and the high amounts of waste produced per unit of emergy expended, will all hinder the stainability of the system in the longer term context. Suggestions for public policy choices, relevant to these findings, are discussed. Ó 2012 Ecological Society of China. Published by Elsevier B.V. All rights reserved.
摘 要 本研究应用综合的环境核算方法–能值分析方法, 基于1987至2007年的数据, 对内蒙古自治区生态经济系统进行 了评估 通过计算内蒙古自治区环境系统和经济系统的输入输出, 以及一系列能值指标, 本研究讨论了内蒙古自治 区的资源利用结构, 经济形势和贸易状况 通过比较内蒙古与中国其他几个省市的系统指标以及国家平均水平, 评 估内蒙古生态经济系统的性能和可持续性 结果显示, 在系统的总利用能值中, 85%以上来自于内蒙古区域内部, 尽管在这20年中这个比例由93.03% 降到了 87.28%, 表明内蒙古有很强自给自足能力 2007年内蒙古系统的能 值持续性指数为1.86, 表明内蒙古系统目前是可持续的, 但难以保证长期的可持续发展 内蒙古存在贸易不平衡, 过于依赖不可更新资源, 环境废弃物所占能值比例过高等问题, 将会阻碍系统的长期可持续性 文章最后给出了 基于这些研究结果的政策建议. Ó 2012 Ecological Society of China. Published by Elsevier B.V. All rights reserved.
1. Introduction Emergy analysis was introduced by Odum in the 1980s . The emergy of a product or service is defined as all the available energy of one kind used up directly or indirectly in the production or service process . This standardization enables the total cost and benefit of these products or services to be compared on a common basis. The standard metric of emergy is the solar emjoule (sej),
* Corresponding author at: Institute of Geographic Sciences and Natural Resources Research, The Chinese Academy of Sciences, Beijing 100101, China. Tel.: +86 (0) 1064888996; fax: +86 (0) 1064859781. E-mail address: [email protected]
which connotes all (i.e. present and past) use of energy required to create the present product or service. Emergy analysis is thus an eco-centered valuation method that compensates for the inability of traditional economic evaluation to fairly evaluate the true, total cost of various products and services. This is in contrast to traditional economic analyses, which typically are based on strictly monetary metrics and embodied energy inputs  that typically consider only fossil fuels inputs. Emergy synthesis provides the potential ability to obtain a reliable evaluation of a region’s ecological and economic system over a defined period of time, and to reasonably compare them with those of other regions. Since emergy functions as a bridge between economic and ecological systems, it more effectively integrates the
1872-2032/$ - see front matter Ó 2012 Ecological Society of China. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.chnaes.2011.12.007
L.P. Zhu et al. / Acta Ecologica Sinica 32 (2012) 74–88
costs and benefits that accrue in the two domains. Emergy syntheses can thus be used to assess complex relationships of economic and ecological systems and to estimate their long term sustainability. Such techniques are essential for properly valuing the contribution of nature to all human economic activities and for meeting the demands of sustainable development . Emergy-based research at regional, provincial and national scales have now been performed for many locations, including those in China, United States, Italy, and so on [4–14]. Abundant with natural resources, the Inner Mongolia Autonomous Region (IMAR) is China’s third largest province, largest coal producing region and one of the leading provinces in electricity generation. The Western China development plan of 2000, ushered in an economic boom in IMAR, with an average annual growth of 17.5% in the Gross Domestic Product (GDP) from 2000 to 2009 . However, this economic growth was at the expense of high rates of resource consumption, which may have an adverse effect on IMAR’s long-term sustainability. The west to east energy transfer strategy of western development provides large sums of money to the IMAR economies while addressing energy shortages in eastern China. However, this strategy is based on the substantial export of coal, and/or a west to east transfer of electricity generated by local coal-fired plants in the IMAR. Given the negative by-products of this strategy, it is a major challenge for policy makers to balance the needs of human and natural systems in the IMAR, via a fair evaluation of the contributions of nature and the economy to human well-being [16–18]. The purpose of this work then, is to assess the present, real wealth of the IMAR, to evaluate the performance and sustainability of the ecological–economic system of the IMAR over time, and to place these results within those of the larger Chinese system as a whole. Economic prosperity, in this context, is seen as dependent not just on contributions from various goods and services, as traditionally valued, but also on various environmental resources that would otherwise be either discounted, or ignored completely. Specifically, the most common traditional metric for large-scale economic accounting, GDP, excludes the often numerous environmental costs of economic development. Emergy analysis can more effectively evaluate these rates and conversions. Some work using this general approach in the IMAR has already been done [9,19,20]. Using data of 1987–2007, we here present an updated accounting, and an integrated analysis of sustainability, of the IMAR system. Specifically, this work quantifies and standardizes the main fluxes of energy, materials and money that flow through and within the boundaries of the region. Temporal variation of indices are explored for the evaluation, then the emergy results are compared with those for Gansu, Liaoning, Ningxia and selected national indices.
2. Methods In emergy analysis each form of energy, material, or service in the system is translated into a common metric, i.e. solar emergy, by way of multiplying energy requirements by a conversion factor (referred to as solar transformity, i.e. the energy embodied in a given product or service . Odum, arguing that ‘‘the position in the energy hierarchy is measured with transformities” , has, along with others, estimated transformities for various products and services [1,21–24]. The transformities used here have been calculated using the planetary baseline of 15.83 1024 sej year1 . Five principal steps are required to complete an emergy evaluation. First, a comprehensive and detailed energy system diagram is constructed, representing the interactions between any and all economic and environmental components of the system deemed important. The second step transforms this detailed diagram into
a more general, aggregated one according to the best existing understanding of the functional relationships between the various components and processes of the system. Third, metrics quantifying the flows between components in the aggregated diagram are converted to emergy values, via estimated transformity rates. Fourth, the raw data, quantified in traditional metrics and needed to estimate the emergy exchanges, are obtained from various sources (see below). Lastly, emergy indices are calculated, and estimates of system sustainability are made [1,25]. The latter are based on concepts of ‘‘maximum empower” and other sustainable environmental management principles . A comparison of emergy analysis results of the IMAR with those of other regions and China is conducted to help characterize the IMAR’s emergy status the IMAR within the larger context of regions and the nation as a whole. Absolute emergy-based values are not very telling for a comparison, composite emergy indicators such as emergy use per person, emergy/dollar ratio, dependent on both emergy used and actual measures of system’s size (population, area, GDP), are used in order to be fully understood. Although some emergy indices are missing in our comparisons, we tried best to keep the consistency of comparison and simultaneity of the same emergy index between different regions. All the calculated indices in these comparisons are based on the same transformity base line, 15.83 1024 sej year1. Data sources for this research are from publicly issued yearbooks. Detailed information on local resources production and consumption, imports and exports come from Inner Mongolia Statistical Yearbook; data on IMAR’s energy production, consumption and circulation come from the China Energy Yearbook and China Statistical Yearbook; data on IMAR’s iron ore production and circulation come from the China Steel Yearbook [26–29].
3. Study area The IMAR (97°110 2000 –126°100 40E; 37°120 4000 –53°120 3000 N) is situated on China’s northern frontier, covers an area of 1.183 million km2, and is inhabited by 24.13 million people. The region’s topography is dominated by a mid to low elevation plateau area, much of at approximately 1000 m above sea level. The majority of the area is dominated by a continental, temperate monsoon climate. The IMAR has an estimate of 151 thousand km2 of cultivated land, 474.8 thousand km2 of grassland, and 89.6 thousand km2 of forests in 2004 . Its grassland area is one fourth of China’s total, and its forested area is the second largest among Chinese provinces. Its coal reserves, iron ore reserves and rare-earth resources are well known and very large. It also has substantial mineral products such as asbestos, millstones and mica. The biggest rare earth metal ore deposit in China is in IMAR, with reserves amounting to 4360 million tons, which is 81.2% of China’s total reserves and 54.2% of world reserves . The IMAR’s mainstay industries are related to energy, metallurgy, agricultural and livestock products, and chemical production. The IMAR acts as an important ecological shelter of northern China. According to the IPCC’s Fourth Assessment Report (FAR, http://www.ipcc.ch/, 2007), certain processes and components of the IMAR ecosystem will be increasingly vulnerable to future climate changes. These include increasing aridity, rangeland condition degradation, land desertification, soil erosion, reduction in available water resources, and rapid decreases in forest resources. These problems originate in issues of over-population, over-grazing, unsustainable resource use, and the adverse effects of droughts exacerbated by climate change . Environmental managers and policy makers have historically taken insufficient consideration of these factors when evaluating the contributions of natural systems
L.P. Zhu et al. / Acta Ecologica Sinica 32 (2012) 74–88
to economic development, with negative results. Remedial or restorative measures, such as the fencing off or forbidding of grazing in degraded grassland areas, have been taken to try to limit damage. However, recent research shows that at least some of these measures may not be very effective . In the past two decades, the IMAR’s human population, and its GDP, grew significantly. In 2007 the IMAR’s GDP totaled 8.25 1010 USD, an enormous increase from the estimated 2.56 109 USD in 1987 . Farming and animal husbandry, particularly sheep and goat herding, are the traditional methods of subsistence. However, emphasis on industrial and economic growth during the last two decades has greatly transformed this region, and with it has come an increasing pressure on natural ecosystems. The ability to maintain a balance between economic growth and ecosystem stability, and thus foster long term societal sustainability, has become a serious challenge facing the people of the IMAR.
4. Results and discussion 4.1. Emergy flows of the IMAR A detailed energy system diagram of IMAR is given in Fig. 1 for overview. It provides a guide to understand the system and the basis for developing emergy accounts. The detailed items with their corresponding values listed and evaluated in Table 1, the meanings of symbols are given in detail in Odum’s work . The free environmental energy sources (sunlight, wind, rain and so on), as well as resources imported from the outside economy, are shown as circles around the system boundary. The primary transformation processes are forests, agriculture and livestock breeding. Secondary transformation processes are mining, power generation, manufacturing industry, followed by services and commerce, people, and higher social structures, such as markets and tourism. The annual emergy flows into and out of the IMAR system during 1987–2007 are summarized in Table 1, under four principal categories: renewable resources (R), nonrenewable resources derived from storages within the region (N), imported emergy, and
export emergy. Nonrenewable resources within the region (N) are categorized into dispersed rural resources (N0) (resources that are used faster than they are renewed such as soils or forest biomass harvested at unsustainable rates) and (N1) non-renewable resources (fossil fuels and minerals). Imported emergy includes: fuels and minerals (F), goods (G), and the services embodied in these imports (P2I). Exports from the region include: non-renewable resources (N2) that are exported without upgrading in the economy, finished products (B), and services and labor (P1E) embodied in B. Table 2 similarly identifies the summary flows of emergy and money in the IMAR. Table 3 presents a series of different emergy-based indices that help in further characterizing the condition of the IMAR. Fig. 2, a summarized diagram of the IMAR in 2007, gives an overview of the renewable resources, nonrenewable resources, imported emergy, and exported emergy for the IMAR. Quantities that can be identified from Fig. 1, together with Table 3, are as follows: (1) total emergy used (U) in 2007 (estimated at 1.3492 1024 sej), which estimates the IMAR’s annual wealth; (2) renewable resources (accounting for 19.93% of the total emergy used); 54.03% (calculated as (F1 F)/U) of the emergy used was from local nonrenewable resources; 33.25% (calculated by (R + N0)/U) of emergy use was from free resources; emergy use in exports was 3.6 times as much as that in imports; 33.96% (calculated by N2/N1) of the nonrenewable emergy produced was exported without use of the IMAR system itself. The results clearly show that IMAR largely depended on local nonrenewable resources in 2007. Fig. 3 shows the trend of total emergy used and GDP over the period between 1987 and 2007. Both increased with time, rising from 5.81 1023 sej and 2.564 109 $ respectively, in 1987, to 1.349 1024 sej and 8.246 1010 $ in 2007. The yearly variation of components of the total emergy use of the IMAR are presented in Fig. 4a.
4.1.1. Renewable resources and renewable production The renewable sources (R) are identified as solar radiation, tides and the deep heat of the earth. In order to avoid double-
Fig. 1. A detailed energy systems diagram of IMAR, 2007.2007年内蒙古详细的能量系统图.
L.P. Zhu et al. / Acta Ecologica Sinica 32 (2012) 74–88 Table 1 Annual evaluation of resource basis for the IMAR in 2007.a Item
Solar emergy (sej year1)
2007 Emvalue (em $)
Renewable resources within inner Mongolia Incident solar radiation 5.62E+21–7.69E+21 Wind kinetic energy 9.72E+18 Rain, geo-potential on land 3.00E+18 Rain, chemical potential 1.46E+18 Earth cycle energy 2.24E+18
J J J J J
1 2510 (Odum, 1996) 46600 (Odum, 1996) 31200 (Odum, 1996) 56000 (Odum, 1996)
5.62E+21–7.69E+21 2.44E+22 1.40E+23 4.56E+22 1.289E+23
8.167E+08 3.240E+09 1.858E+10 6.056E+09 1.712E+10
6 7 8 9 10 11
Renewable production within inner Mongolia Hydro electricity produced 1.41E+16 Hydro electricity used 1.41E+16 Fish production 4.24E+13 Timber production 4.01E+16 Agricultural products 3.53E+17 Livestock 6.16E+16
J J J J J J
2.06E5 (Odum, 1996) 2.06E5 (Odum, 1996) 3.35E6 Odum et al.(1998) 1.17E5 (Tilley, 1999) Variable Brandt (Brandt–Williams, 2001 (revised 2002)) Variable (Brandt–Williams, 2001 (revised 2002))
2.90E+21 2.91E+21 1.42E+20 4.69E+21 1.355E+23 9.93E+22
3.852E+08 3.871E+08 1.888E+07 6.229E+08 4.853E+10 1.32E+10
12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Annual production and use of nonrenewable resources in 2007 Salt 2.46E+12 g Electricity production 6.66E+17 J Electricity used 4.40E+17 J Fertilizer 8.43E+11 g Crude oil production 6.96E+16 J Crude oil used 5.96E+16 J Natural gas production 2.75E+17 J Natural gas used 1.03E+17 J Coal used 3.88E+18 J Coal production 7.41E+18 J Calcium carbide 5.64E+12 g Pyritel ore 4.68E+11 g Iron ore 5.61E+13 g Aluminum 1.02E+12 g Soil erosion 3.75E+17 J
1.00E9 (Odum, 1992) 2.91E5 (Odum, 1996) 2.91E5 (Odum, 1996) 5.11E9 (Odum, 1996) 92700 (Bastianoni et al., 2005) 92700 (Bastianoni et al., 2005) 80500 (Bastianoni et al., 2005) 80500 (Bastianoni et al., 2005) 67100 (Odum, 1996) 67100 (Odum, 1996) 4.63E9 (Odum, 1996) 4.63E9 (Odum, 1996) 6.00E9 (Campbell, 2009) 4.63E9 (Odum, 1996) 1.24E5 (Odum, 1996)
2.46E+21 1.94E+23 1.28E+23 4.31E+21 6.45E+21 5.52E+21 2.21E+22 8.32E+21 2.604E+23 4.971E+23 2.61E+22 2.16E+21 3.363E+23 4.74E+21 4.65E+22
3.27E+08 2.57E+10 1.70E+10 5.72E+08 8.57E+08 7.34E+08 2.94E+09 1.11E+09 3.46E+10 6.60E+10 3.47E+09 2.88E+08 4.47E+10 6.30E+08 6.18E+09
27 28 29 30 31 32
Annual imports to the inner mongolia economy in 2007 Coal 1.86E+17 J Petroleum 3.33E+17 J Metal ores 3.43E+12 g Fertilizers 1.01E+12 g Goods 2.64E+21 g Services 8.76E+09 $
67100 (Odum, 1996) 92700 (Bastianoni et al., 2005) 4.63E9 (Odum, 1996) 5.11E9 (Odum, 1996) Variable 7.53E+12
1.25E+22 3.09E+22 1.58E+22 5.16E+21 6.45E+21 6.60E+22
1.66E+09 4.10E+09 2.11E+09 6.85E+08 8.57E+08 8.76E+09
67100 (Odum, 1996) 92700 (Bastianoni et al., 2005) 4.63E9 (Odum, 1996) 2.91E5 (Odum, 1996) Variable
2.55E+22 4.90E+21 5.65E+19 7.20E+22 1.75E+22
3.38E+09 6.51E+08 7.51E+06 9.557E+09 2.324E+09
1.88E7 (Zhou et al., 2009) 1.07E10 (Brown and Buranakarn, 2000)
38 39 40 41 a
1 2 3 4 5
33 34 35 36 37
Annual exports from the inner mongolia economy in 2007 Coal 3.79E+17 J Petroleum 5.28E+16 J Metal ores 1.22E+10 g Electricity 2.47E+17 J Goods 1.65E+16 J 1.42E+12 g Services 1.96E+10 $ Tourism 5.30E9 $ Waste Waste water 2.50E+14 g Solid wastes 1.10E+14 g
All flows are evaluated on a yearly basis (see footnotes, Appendix A). References for transformities are given in Appendix B; footnotes in Appendix A.
counting, renewable emergy sources received are defined as the sum of the largest item of each source, for IMAR, the geo-potential energy of rain and the earth-cycle energy. The renewable sources of IMAR from 1987 to 2007 remain fairly constant with time (3.00 1023 sej year1), and correspond to a decreased fraction of total emergy use (from 47.83% in 1987 to 19.93% in 2007). The largest source of renewable production in the IMAR is from agriculture, followed by livestock production. Agricultural and livestock production increased respectively from 5.36 1022 sej and 1.29188 1022 sej in 1987, respectively, to 1.35 1023 sej, 9.93 1022 sej in 2007. In 2007, they respectively accounted for 56% and 41% of total renewable resource production.
IMAR economy with most of the driving forces (Fig. 4a). The largest production of emergy from non-renewable sources in the IMAR is coal production, followed by iron ore production and calcium carbide production, which increased respectively from 6.72 1022 sej, 4.67 1022 sej, and 2.6 1020 sej in 1987 to 6.99 1023 sej, 3.363 1023 sej, and 2.61 1022 sej in 2007, accounting for respectively 63%, 30% and 2% of the concentrated non-renewable resources production (N1 + N2). Use of fuels (fossil energy) increased from 6.54 1022 sej in 1987 to 4.06 1023 sej in 2007, which takes 30% of the total emergy use. In 2007, coal supplied 90.50% of the emergy in the energy used within the IMAR, followed by natural gas (2.41%), petroleum (1.39%), and hydro-power (0.33%) [26–29].
4.1.2. Production and use of nonrenewable resources Local non-renewable resources (N), increased from 2.023 1023 sej in 1987 to 1.190 1024 sej in 2007, provide the
4.1.3. Imports and exports In 2007, emergy imported accounted for about 16.92% of the total emergy used. As shown in Fig. 4b, from 1987 to 2007, the total
L.P. Zhu et al. / Acta Ecologica Sinica 32 (2012) 74–88
Table 2 Summary of flows in the IMAR economy (1987–2007). Item R N N0 N1 N2 F F1 F2 G PI I B PE E PE4 GDP P2 P1
Renewable emergy received Nonrenewable source flows Dispersed rural source Mineral prod (fuels, etc.) Fuels exported without use Imported minerals Minerals used (F + N1 N2) Indigenous minerals used (N1 N2) Imported goods (materials) Imported services, total Dollars paid for all imports Exported prod (goods + elec.) Exported services, total Dollars paid for all exports Emergy purchased by Tourists Gross domestic product China emergy/$ ratio Inner Mongolia emergy/$ ratio
sej year sej year1 sej year1 sej year1 sej year1 sej year1 sej year1 sej year1 sej year1 sej year1 $ year1 sej year1 sej year1 $ year1 sej year1 $ year1 sei $1 sei $1
2.779E+23 2.818E+23 1.644E+23 1.174E+23 1.915E+22 1.575E+22 1.140E+23 9.827E+22 1.364E+22 1.109E+22 3.369E+08 1.418E+22 2.174E+22 6.604E+08 6.384E+20 2.56E+09 3.293E+13 2.266E+14
3.359E+23 3.167E+23 1.651E+23 1.516E+23 3.180E+22 1.674E+22 1.365E+23 1.198E+23 7.964E+21 8.842E+21 2.850E+08 1.738E+22 2.060E+22 6.355E+08 7.777E+20 3.86E+09 3.242E+13 1.696E+14
3.043E+23 3.959E+23 1.687E+23 2.272E+23 5.609E+22 1.458E+22 1.857E+23 1.711E+23 2.916E+20 1.464E+22 7.552E+08 1.766E+20 3.496E+22 1.803E+09 3.947E+21 1.04E+10 1.939E+13 6.505E+13
2.542E+23 4.005E+23 1.809E+23 2.196E+23 6.019E+22 5.151E+22 2.109E+23 1.594E+23 3.068E+21 2.542E+22 2.070E+09 2.325E+22 3.952E+22 3.218E+09 1.193E+22 1.86E+10 1.228E+13 3.627E+13
2.621E+23 9.072E+23 1.812E+23 7.260E+23 2.647E+23 6.826E+22 5.296E+23 4.613E+23 1.218E+22 6.814E+22 6.911E+09 5.021E+22 9.798E+22 9.937E+09 5.279E+22 4.83E+10 1.050E+13 2.182E+13
2.689E+23 1.284E+24 1.797E+23 1.104E+24 3.748E+23 9.229E+22 8.213E+23 7.290E+23 6.455E+21 7.285E+22 9.674E+09 8.979E+22 1.476E+23 1.960E+10 8.503E+22 8.25E+10 7.530E+12 1.636E+13
Table 3 The IMAR emergy indicators and indices (1987–2007). Name of index
Renewable emergy received (sej year1) Indigenous non-renewable (sej year1) Imported emergy (sej year1) Total emergy inflows (sej year1) Total emergy used (sej year1) Total exported emergy (sej year1) Emergy yield Emergy used from home sources (%) Imports–exports (sej year1)
R N0 + N1 F + G + PI R + F + G + PI U = R + N0 + F1 + G + PI B + PE + N2 Y = R + N + F + G + PI (N0 + F2 + R)/U (F + G + PI) (B + PE + N2) (B + PE + N2)/(F1 + G + PI) R/U (F + G + PI)/U (R + N0)/U (F1 + G + PI)/(R + N0) (F + N + G + PI)/(R) (F + G + PI)/(R + N) U/Area U/Population U/GDP U/GNP El/U (R/U) (population)
2.779E+23 2.818E+23 4.048E+22 3.184E+23 5.810E+23 5.507E+22 6.002E+23 93.03 1.459E +22 1.36
3.359E+23 3.167E+23 3.354E+22 3.694E+23 6.543E+23 6.979E+22 6.861E+23 94.87 3.624E +22 2.08
3.043E+23 3.959E+23 2.951E+22 3.338E+23 6.736E+23 9.122E+22 7.296E+23 95.62 6.171E +22 3.09
2.542E+23 4.005E+23 8.000E+22 3.342E+23 6.745E+23 1.229E+23 7.347E+23 88.14 4.295E +22 1.54
2.621E+23 9.072E+23 1.486E+23 4.107E+23 1.053E+24 4.129E+23 1.318E+24 85.89 2.643E +23 2.78
2.689E+23 1.284E+24 1.716E+23 4.405E+23 1.349E+24 6.122E+23 1.724E+24 87.28 4.406E +23 3.57
47.83 6.97 76.12 0.31 1.16 0.07 4.91E+11 2.81E+16 2.27E+14 3.29E+13 1.49% 9.88E6
51.33 5.13 76.57 0.31 1.04 0.05 5.53E+11 3.03E+16 1.70E+14 3.24E+13 1.95% 1.11E7
45.17 4.38 70.21 0.42 1.40 0.04 5.69E+11 2.95E+16 6.50E+13 1.93E+13 2.91% 1.03E7
37.69 11.86 64.51 0.55 1.89 0.12 5.70E+11 2.84E+16 3.63E+13 1.23E+13 3.98% 8.94E6
24.89 14.11 42.09 1.38 4.03 0.13 8.90E+11 4.41E+16 2.18E+13 1.05E+13 6.65% 5.94E6
19.93 12.72 33.25 2.01 5.41 0.11 1.14E+12 5.61E+16 1.64E+13 7.53E+12 9.49% 4.79E6
7.91E7 14.825 12.79 2.07E+07 1.18E+12
8.88E7 20.455 19.62 2.16E+07 1.18E+12
8.26E7 24.725 17.69 2.28E+07 1.18E+12
7.15E7 9.184 4.90 2.37E+07 1.18E+12
4.75E7 8.870 2.21 2.39E+07 1.18E+12
3.83E7 10.048 1.86 2.41E+07 1.18E+12
Ratio of export to imports Fraction use, locally renewable (%) Fraction of use purchased import (%) Fraction of use that is free (%) Ratio of purchased to free Environmental Loading Ratio(ELR) Emergy Investment Ratio(EIR) Use per unit area (sej m2) Use per person (sej capita1) Inner Mongolia emergy/$ ratio China emergy/$ ratio Ratio of electricity/emergy use Renewable carrying capacity at present standard of Living (capita) Developed carrying capacity at same living standard Emergy yield ratio (EYR) Sustainability indexPopulation (capita) Area (m2)
8(R/U) (population) 1 + 1/EIR, Y/(F + G + PI) EYR/ELR
imports increased from 4.048 1022 sej to 1.716 1023 sej while the exports increased from 5.507 1022 sej to 6.122 1023 sej. Before 2001 imports and exports of the IMAR increased very slowly. After 2001, the growth of exports exceeded that of imports, resulting in total exports being 4.75 1023 sej more than total imports in 2007. This rapid increase was due to the rapid growth of coal and electricity exports after 2001. In 2007, the import/export emergy ratio (3.46) indicated a large imbalance in the exchange of real wealth with other Chinese provinces and foreign countries. However, when coal (3.44 1023 sej in 2007) is removed from the import–export balance, the import/export emergy ratio changes greatly, such that emergy imports are actually 2% larger than exports. The imports include mainly metal ores, oil, coal and human services; the exports from the IMAR include mainly coal, electricity and human services.
4.2. Comparison of emergy situation of the IMAR with those of other regions and the larger Chinese system as a context Emergy based indices led to insights on the development and utilization of the region’s natural resources. In this study, we compared indices of the IMAR with those of Gansu, Liaoning, Ningxia provinces and some selected national indices of China (Table 4). Gansu province covers an area of about 454,400 km2, and the total population in 2004 was approximately 26.18 million, of which about 29% live in the city. Economy for Gansu province continued to grow at a relatively high speed during the period of 1994–2004. The annual growth rate of GDP is above 9%. Its GDP reached 1.86 1010 USD in 2004. Water resource in Gansu is very deficient as the yearly precipitation is less than 400 mm in most localities. In Gansu there are well-found category mineral
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Fig. 2. Aggregated flows of the IMAR economy 2007.2007年内蒙古经济系统综合能值系统图.
Fig. 3. Total emergy used (defined as the sum of R + F + G + P2I + N0 + N1) and GDP of IMAR from 1987 to 2007.内蒙古1987-2007年总能值使用量与GDP发展趋势.
resources, of which most the reserves are small and most are overexploited. Liaoning province is the overlapping region of the Bohai sea rim economic circle and the Northeast Economic Region. It covers the land area of 148,000 km2, the sea area of 150,200 km2. The total population of Liaoning in 2005 was approximately 41.9 million, of which about 58.70% live in urban areas. Its GDP reached 9.78 1010 USD in 2005, up 12.3% over the same period of last year. Liaoning is abundant with natural resources, on which its economy chiefly relies. As one of the oldest industrial bases, Liaoning’s high speed development of economy is at the expense of over-exploitation of the non-renewable resource. Ningxia Province covers an area of about 51,800 km2, and the total population in 2006 was approximately 6.007 million, of
which town population is about 43%. In 2006, its GDP had reached 9.05 109 USD, up by 17.86% over 2005. The annual growth rate of GDP is above 9% during the period of 2000–2006. Ningxia is abundant in energy minerals, of which per capita amount occupies the second place of China. But exploitation and utilization of energy minerals in Ningxia remains relatively undeveloped.
4.2.1. The fraction of emergy use derived from home sources From 1987 to 2007 approximately 84.81% to 95.62% of the emergy used in the IMAR was derived from home sources (i.e. from within the IMAR), reflecting a high potential for self-sufficiency and economic security. This ratio presents downtrend basically. As shown in Table 4, the four regions were all highly self-sufficient.
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activity than the average, and therefore, environmental resources may be available locally and capable of stimulating investment and additional economic use. The emergy investment ratio in the IMAR during 1987 and 2007 is from 0.04 to 0.16, representing an ascending trend. The EIR values for the four regions were all very low (Table 4), ranging from 0.05 in Gansu to 0.19 in Ningxia, all much lower than the national average (0.49).
Fig. 4a. Trends in IMAR’s components of total emergy used of IMAR from 1987 to 2007.内蒙古1987-2007年总能值使用量组分及其发展趋势.
4.2.3. Emergy use per person Emergy use per person (average per-capita share of the annual emergy use of a region) is an indicator of the overall quality of life, and of the level of economic development of the region. It also facilitates comparisons between developed and developing regions; developing regions are very often supported by large inputs of environmental emergy. As shown in Fig. 5a, during 1987–2007, the population in the IMAR increased from 20.66 million to 24.05 million, and the emergy use per person increased from 2.11 1016 sej to 4.22 1016 sej. This index was the highest of the four regions by a considerable margin. After 1999, this index increased very rapidly tracking IMAR’s changing living standard. 4.2.4. Ratio of electricity to emergy use The IMAR is one of the nation’s largest electricity generators. In 2007, the IMAR generated over 180 billion kW h of electricity and delivered over 68 billion kW h to surrounding provinces and cities. Regions with a high proportion of electrical emergy tend to have high levels of technology contributing to high standards of living. As shown in Fig. 5b, the fraction of electricity/emergy use increased from 1.49% to 9.49%, below the average of China year by year, and much less than that of Gansu (21%) and Ningxia (25.50%).
Fig. 4b. Trend of total imports and exports of IMAR.内蒙古1987-2007年输入能值与 输出能值.
4.2.2. Emergy investment ratio (EIR) The investment ratio is the emergy feedback from the economy outside the system divided by the indigenous emergy inputs (N + R) . This ratio measures the emergy inputs from the economy outside the system that are needed to exploit a unit of indigenous local resource. Lower values indicate that more of the indigenous environmental resources are available per unit of economic
4.2.5. Emergy use per unit area Emergy use per unit area is indicative of the average intensity of development in a system. For the IMAR, in 2007 48.5% of the land area is covered by grassland, 9.2% is covered by forests and 8.6% is used for agriculture. Emergy use per unit area can be high in very industrialized countries or areas, which suggests land to be a limiting factor for the future economic growth of the region . Emergy use per unit area of the IMAR (Fig. 5b) increased from 4.91E11 sej m2 in 1987 to 1.14 1012 sej m2 in 2007, which is much less than that of Liaoning (6.31 1012), Ningxia (2.25 1012) and the national average level (2.34 1012). This indicates that the IMAR has a less concentrated emergy use than those areas.
Table 4 Comparison of emergy indices for Inner Mongolia, China, Gansu, Liaoning and Ningxia. Index
Inner Mongolia 2007
Area (m2) Population ind. Renewable emergy flow (sej year1) Nonrenewable emergy flow (sej year1) Imported emergy (sej year1) Totalemergy used(U) (sej year1) Exported emergy (sej year1) Percent renewable (%) Emergy used from home sources (sej year1) Ratio of exports to imports Emergy/$ ratio (sej $1) Emergy investment ratio (EIR) Environmental loading ratio (ELR) Emergy yield ratio (EYR) Emergy sustainability index Use per unit area (sej/m2) Use per person (sej/ind.) Ratio of electricity/emergy use (%)
1.18E+12 2.07E7 2.689E+23 9.484E+23 1.716E+23 1.014E+24 6.122E+23 19.93 87.28% 3.57 1.63E+13 0.11 4.02 10.05 2.50 1.14E+12 5.61E+16 9.49
9.6E12 1.307E9 2.79E+24 1.29E+25 6.72E+24 2.25E+25 5.19E+24 12.43 70.05% 0.77 9.86E+12 0.49 7.41
4.54E+11 2.62E7 1.43E+23 8.52E+22 1.12E+22 2.38E+23 2.50E+21 60.42 0.95 0.22 1.25E+13 0.05 0.67 21.4 31.82 5.22E+11 9.05E+15 21
1.48E+11 4.19E7 1.21E+23 7.73E+23 9.80E+22 9.35E+23 5.85E+22 13 0.9 0.6 9.56E+12 0.11 7.18 10.13 1.41 6.31E+12 2.23E+16
5.18E10 6.01E6 1.01E+22 1.37E+23 2.72E+21 1.49E+23 2.36E+21 6.70 0.97 0.87 1.68E+13 0.19 13.84 54.96 3.97 2.25E+12 2.47E+16 25.50
2.34E+12 1.71E+16 10.77
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Fig. 5. (a) Trend of population, emergy use per person. (b) Trend of emergy use per area and ratio of electricity/emergy use.内蒙古1987-2007年人口及人均能值使用量 内蒙古 1987-2007年能值密度与电力能值比率.
decreased from 2.266 1014 sej $1 in 1987 to 1.636 1013 sej $1 in 2007, which indicates that the power of a dollar for purchasing real wealth in the IMAR is declining, while the relatively high absolute values at both times indicates that most resources used in economic activities are extracted from the natural environment. The 2007 ratio of the IMAR was lower than that of Ningxia, but higher than those of Liaoning and Gansu. During 1987–2007, the IMAR emergy/dollar ratio was always higher than Chinese emergy/dollar ratio, but the gap was narrowing year by year. The existing gap suggests that the IMAR will lose in most trades with regions that have lower emergy/dollar ratio. The exports of raw materials such as coal and metal ore have a rapid growth after 2001, this transfers much more emergy to the purchasers than what the money received really can buy. So before the IMAR emergy/dollar ratio falls to a critical level, raw materials should be used to make final products with more additional values. Fig. 6. Trend of emergy/$ ratio for IMAR and China.内蒙古与中国能值货币比率.
4.2.6. Emergy/dollar ratio The emergy/dollar ratio (EDR) is calculated by dividing total emergy used by the GDP expressed in U.S. dollars (USD). This ratio connects economic activity to the emergy flows that support the economy in a given year. A higher ratio implies that more natural resources would be consumed to produce the same GDP. Lower development districts may have higher EDR value because the emergy input of those districts may come mostly from natural environmental resources directly. The emergy/dollar ratio also indicates how much the IMAR losses or gains on average when it trades with other regions. As Fig. 6 shows, the EDR of the IMAR
4.2.7. Environmental pressure Environmental pressures are potentially indicated by the ratio of wastes produced to total emergy used. During 1987 and 2007, as illustrated in Fig. 7, the ratio of waste produced to emergy used increased from 0.314 to 0.874; the total waste output increased from 1.82 1023 sej to 1.18 1024 sej. Especially after 2001, the two values increased rapidly. The rising trend of these two curves was similar to the curves of total emergy used and nonrenewable resources, indicating that the IMAR system is farther away from equilibrium as compared to the surrounding environment. Such a result is expected, and is an alarming signal of fragility in times of declining resources. There is an immediate need for policies to
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Fig. 7. Trend of total waste output and waste to total emergy use ratio.内蒙古总废弃物能值生产量及废弃物能值比率.
decrease the environmental pollution and dependence on nonrenewable resources. 4.2.8. Emergy exchange ratio The emergy exchange ratio (EER) is the ratio of emergy received by the buyer, to the emergy given, in a trade or sales transaction. Raw products such as minerals, rural products from agriculture, fisheries and forestry, all tend to have high emergy exchange ratios when sold at market price. This occurs as a result of money being paid for human services but not for the extensive work of nature that went into the original generation of these products. For example, the IMAR exported 3.44 1023 sej of coal (60.9 USD per ton) in 2007 for which it received 1.06 1010 USD. The EER for the IMAR coal in 2007 is as follows: (3.44 1023 sej year1)/[(1.06 1010 year1)(7.53 1012 sej $1)] = (3.44 1023 sej year1)/(8.00 1022 sej year1), which computes to a ratio of 4.3:1. Thus, the net benefit to the buyer of the IMAR coal is 4.3 times the buying power of the money paid. From this preliminary analysis we might estimate that the long term equilibrium price for coal, based on assumed emergy parity of the exchange and the emergy to dollar ratio of the Chinese economy in 2007, would be around 261 USD per ton. For some main export commodities of foreign trade, such as steel, rare earth metals and petroleum, the EER
Fig. 8b. GDP and emergy use (U R N0, abb. ‘‘u”) possibility function of China.中 国GDP和购买能值的关系.
values are, respectively, 12.93, 2.10 and 6.78. Therefore, for these materials, the IMAR contributes large fluxes of real wealth to support growth in the regional, national and global economies that receive them. 4.2.9. The functional relationships between GDP and emergy use (economic component, U-R-N0) Total emergy use (U) includes all kinds of inputs contributing to economic growth. The emergy of some renewable resources (R), for example, varies with precipitation and other climatic drivers which are beyond human control. Here we simply try to establish the functional relationship between GDP and emergy use (U–R–N0, abbreviated to ‘‘u”) in the IMAR system and Chinese system. As shown in Fig. 8a and 8b, along with the increase of emergy use, the GDP increase in China overall is much faster than that in the IMAR, indicating that the IMAR’s economic system is much less competitive than the other provinces and regions of the nation. 4.3. Emergy-based sustainability indicators
Fig. 8a. GDP and emergy use (U R N0, abb. ‘‘u”) possibility function of IMAR.内 蒙古GDP和购买能值的关系.
4.3.1. Percent renewable Percent renewable (%Renew) is the percent of the total emergy driving a process that is derived from renewable sources. In the long term, only systems with a high percentage of renewable
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Fig. 9. (a) Trend of percent renewable and environmental loading ratio. (b) Trend of emergy yield ratio and energy based sustainability index.内蒙古1987-2007年可更新资源 比率及环境负荷率 内蒙古1987-2007年能值产出率及能值持续性指数.
inputs are truly sustainable . As shown in Fig. 9a, during 1987– 2007, the percentage of renewable inputs decreased sharply, from 63.73% to 26.52%, representing an increasingly unsustainable system. However, the index in the IMAR in 2007 was only lower than that of Gansu (60.42%), and was much higher than that of Ningxia (6.7%), Liaoning (13%), and the national average (12.43%), indicating that the IMAR is nevertheless a relatively more sustainable system than those in other provinces. 4.3.2. The environmental loading ratio The environmental loading ratio (ELR ) is the ratio of nonrenewable and imported emergy use to renewable emergy use. A large ELR indicates highly-intensive emergy utilization, and high environmental pressure. As shown in Fig. 9a, the ELR value of the IMAR rose from 1.16 to 5.41 over 1987–2007, which suggests that the pressure of economic activities on local environmental resources grew quickly. After 1998, with the acceleration of exploitation of nonrenewable resources, mainly coal and iron ore, the ELR increased especially quickly. Compared with those of Liaoning (7.18), Ningxia (13.84) and the national average (7.41), the ELR of the IMAR is much lower, suggesting a relatively less severe stress on the environment. Only Gansu (0.67) had a lower ELR than the IMAR. 4.3.3. Emergy yield ratio The emergy yield ratio (EYR ) can be used to evaluate the ability of a given process to exploit local resources. If the emergy
output of a production process is greater than the input from the economic system, the EYR is greater than 1. During 1987 and 2007, the EYR of the IMAR ranged from 5.58 to 18.77 (Fig. 9b), with a decreasing trend over time. The IMAR’s EYR in 2007 was 8.09, which was lower than that of any of the other regions. Ningxia had the highest ratio (54.96) of the four regions.
4.3.4. Emergy based sustainability index Sustainability is determined by emergy yield, renewability of resource utilization, and load on the environment. The emergy based sustainability index (ESI)  is defined as the ratio of the EYR to the ELR. The most sustainable processes in a system will generally have the highest yield ratio (EYR) relative to the lowest environmental loading (ELR) . Values from 1 to 10 indicate a system that is sustainable and vigorous. A low ESI (<1) is indicative of highly developed ‘consumer’ oriented economies, and high ESI (>10) is indicative of economies that have been termed ‘undeveloped’ . In the IMAR, the ESI declined over the study interval. As shown in Fig. 9b, before 2000, an ESI over 10 reflected underdevelopment in the IMAR. After 1998, the ESI was decreasing at a high rate, from 29.85 in 1998 to 1.86 in 2007, indicating rapid economic development. In order to keep the system sustainable in the long run, the declining trend should be contained. The ESI values (Table 4) for the IMAR (1.86), Liaoning (1.41) and Ningxia (3.97) were moderate, and suggest that these regions have attained a suitable ratio of regional development; that of Gansu
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(31.82) is much higher, indicating a strong underdevelopment there. Based on the emergy analyses above, we summarize the situation in IMAR relative to other areas in China as follows. Over the 1987-2007 time period, 2001 appears to have been a turning point for a number of relevant metrics. Before 2001, most emergy flows, ratios and indices developed fairly (or very) slowly. However after 2001, the GDP and the total emergy used, in particular, entered a phase of rapid rate change, increasing from 2.07 1010 USD and 4.361 1023 sej to 8.25 1010 USD and 1.014 1024 sej, respectively. For both, there was a significant difference between the values before and after 2001 (both p < 0.01, t-test). The soaring economic growth of the region closely tracked an accelerating consumption of (mainly nonrenewable) natural resources, such as coal, rare earth metals, and iron ore, and has led to severe and accelerating rates of environmental pollution. Before 2001, locally renewable resources amounted to more than a half of the total emergy used, while after 2001 this fraction dropped sharply, from 51.85% to 26.52% (p < 0.01, t-test). Simultaneously, the exploitation of nonrenewable resources, mainly coal and iron ore, grew very rapidly; the fraction of indigenous, concentrated nonrenewable resources used reached 52% in 2007. Also after 2001, the total exports increased quickly (p < 0.01, t-test) due to the rapid growth of exports of coal and coal-fired electricity. Fast growth of total waste output (p < 0.01, t-test) and the ratios of waste to total emergy used (p < 0.01, t-test) also began around this time. The ESI decreased at a high speed after 1998 (p < 0.01, t-test) and reached its lowest observed value (2.92) in 2007. As shown in Fig. 8a and 8b, there is little sign that this declining trend will decelerate or stop, let alone be reversed. The ESI values for the IMAR (2.92), Liaoning (1.41) and Ningxia (3.97), were all too low for long-term sustainability, promising likely sustainability only for mediumterm time periods at best. These three regions all rely heavily on indigenous, non-renewable resources, imported emergy being accordingly low. In order to obtain the goal of a healthier and more sustainable socio-economic system, remedial policy measures must be taken. Trends for development of the IMAR and that of China are very similar. According to Yang , after 2000, China stepped into a stage of rapid growth in all aspects of the economy. The concentrated emergy use increased from 8.63 1024 sej in 2000 to 1.34 1025 sej in 2005. Also, the ratio of emergy use per unit area and emergy use per person showed a trend of rapid increase, accompanied by more pressure on environmental resources. China is striving for coordinated regional economic development, while solving the energy shortage problem in eastern China, through a western China development plan. This development drive was officially rolled out in 2000 in 12 provinces, municipalities, and autonomous regions in the western region, of which the IMAR is one. For the IMAR, three development goals were put forward by the government: (1) promoting processes of industrialized agriculture, (2) new industrialization and (3) increased urbanization. An important goal is to develop the IMAR into an important base for farming and stockbreeding production, energy and raw materials-based industrial development, and research into and production of, rare earth metals. One focus of the western China development plan is a west to east energy transfer, including coal, liquid fuel, and electricity transfers. From 1999 to 2009, the accumulative electricity transferred to eastern regions from the IMAR reached more than 94 billion kwh , about 99% of which was generated from coal-fired power plants. The total primary energy consumption of China increased accordingly, and sharply, from 143119 to 265583 million tons standard coal from 2001 to 2007, equating to a 10.8% per annum growth rate . As the major energy supplier to Northeastern and Northern China, the IMAR’s export of coal to other regions in China increased rapidly after 2001.
5. Conclusions and policy suggestions 5.1. Balance of trade Trade between the IMAR and outside areas is not balanced for two main reasons. First, IMAR imports much less emergy than it exports, i.e., it currently gains less real wealth than it loses. Large amounts of energy resources have been exported to meet China’s extremely rapidly increasing energy consumption. The IMAR is richly endowed with fuel and mineral resources, and is China’s second largest coal producing region. The consumption of coal accounts for 70% of the total energy consumption of China , and this tendency shows no sign of decreasing any time soon. Coal dominates the emergy flows and economic activities, and has apparent environmental impacts in the IMAR. The emergy of coal produced in the IMAR in 2007 was equal to 51% of the total emergy used in the region. About 52.9% of the coal mined in the IMAR was exported in 2007. The coal exported without being used by the IMAR itself accounts for almost 100% of the difference between the emergy exported from, and the emergy imported to, the IMAR. Secondly, the EDR of the IMAR is much higher than the mean EDR in China, which means the IMAR will lose in most inter-regional trades, resulting in a trade inequity. With increasing trade and exchange, there will be a growing imbalance in energy and resource use between the IMAR and other areas of China. 5.2. Standard of living of the IMAR The quality of life in the IMAR as measured by the emergy use per person is 2.5 times the national average. This index is also high in Liaoning (1.3 times the national average) and Ningxia (1.4 times the national average), but many conventional social indicators are depressed . For example, the indicators of per capita net income of rural and urban residents, and expenditures of rural and urban residents of the three regions were all below the national average level. This paradoxical situation can occur if the benefits of high emergy use are not accurately and completely conveyed to people by the economic system. The IMAR does not maintain a value-added surplus in the products it provides to the nation relative to those that it receives. The high emergy use per person comes in large part from coal mining. Much of the emergy value of this coal is not included in the dollar flows received for it, which affects the amount of emergy that can be purchased from outside the region. Thus, in the IMAR there is the paradoxical condition in which the emergy per person is high but the quality of life shown by traditional social indices is low. If monetary/economic exchanges between the IMAR and other regions accounted for the unrecognized and or under-valued services generated by natural processes, and this money was spent to benefit the people of the region, the IMAR would have the high quality of life indicated by their emergy use per person. 5.3. Suggestions for public policy in the IMAR Emergy analysis results should be taken into account by public policy makers in order to fairly value the various contributions made by human economies and natural processes. Based on the emergy based analyses above, we recommend the following. First, the establishment of an effective resource pricing system is needed. The government should promote resource price reform and should gradually formulate a pricing mechanism that more properly reflects the actual but under-valued work of nature, resource scarcities, market demand and supply, and the various costs of pollution control and/or remediation. A resource tax introduced in the far-western Xinjiang region in June 2010 to help save energy, cut emissions and boost prosperity will be extended to the rest of
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the country by 2015. Raising prices to eliminate the emergy advantage to the buyer of natural resources by reducing the EER of non-renewable resources to 1, the equilibrium level, must be done. Second, indigenous resources should be processed in the home region, i.e. locally, before export. Lowering the EER of exported commodities, by decreasing the proportion of direct environmental resource inputs not paid for, should be considered. After processing, the price of resources having ‘‘added value” would rise, reducing trade losses. Importing goods and fuels from regions with higher EDR rates is another way to reduce such losses. Third, increased agricultural efficiencies should be promoted. With the gradual decline in the availability of cheap nonrenewable resources, the importance of renewable resources will be recognized, and agriculture might once again become the mainstay of the economy in these mostly rural regions. For the IMAR, about 96% of the land area is covered by grasslands, forests and farms. The use of organic fertilizers, and increased reliance on laborintensive land management practices instead of mechanized use of fuels, and application of chemical fertilizers and pesticides, will be effective in increasing the EYR, thereby increasing the likelihood of long term sustainability. The protection of grasslands and forest resources in order to maintain the sustainable development of animal husbandry and forestry, will help bring the IMAR closer to achieving the larger goal of optimum emergy production. Agricultural residues and livestock wastes can be recycled or converted to biomass fuels, to further increase the overall efficiency of the system, without impairing energy security. Fourth, more emergy should be properly imported to IMAR. To maintain a system sustainable and vigorous, we can only control the amount of indigenous nonrenewable resources and imported emergy to adjust the proportions of resources within an appropriate range, since the amount of renewable resources supporting an economy is a constant function of a region’s geography and climate. Under the condition of a small EIR, IMAR should appropriately import more goods and resources with EER values larger than 1, to reduce dependence on local nonrenewable resources. Acknowledgements This research was supported by NASA (NN-X-09-AM-55G). Financial support from the China Scholarship Council is also appreciated. We thank Dr. Xuejun Dong of North Dakota State University, Central Grasslands Research Extension Center, for his helpful comments on an earlier version of this manuscript. Appendix A. Footnotes to Table 1 1. Solar energy received:
5.61925E+21–7.6895E +21 J year1 Solar energy received (J) =(avg.insolation)(area) Avg. insolation: 4750–6500 MJ/m2 a1  Area: 1.89E+06 J m2 year1  2. Kinetic energy of wind used at the surface: 3.40278E +19 J year1 Wind energy = (density)(drag coeff.)(geostrophic wind velocity)3(area)(sec/year) Calculated in Odum (1999) ‘‘Evaluating Landscape Use of Wind Kinetic Energy” air density 1.3 kg m3 wind velocity(metric) 3.7 ms1  Geostrophic wind 6.17 ms1 drag coeff. 3.00E03 area 1.18E+12 m2 sec/year 3.14E+07
3. Rain chemical potential: 3.00269E+18 J year1 Chemical potential energy in rain = (area) (rainfall) (density water) (gibbs free energy water relative to seawater) Area 1.18E+12 m2 Rainfall 0.259 m year1  Gibbs free energy (Odum, 4.77 J g1 1996) Density 1.00E+06 g/m3 4. Geopotential energy of rain: 4.58E+17 J year1 Geo-potential energy = (area) (mean elevation) (rainfall) (density) (gravity) Area 1.18E+12 m2 mean elevation 1000 m  rainfall 0.259 m year1  density 1.00E+06 g/m3 gravity 9.8E3 N/g 5. Earth cycle energy: 1.39E+17 J year1 Earth cycle energy = (land area) (heat flow/area) Area 1.18E+12 m2 Heat flow/area 60 mW m2  1.89E+06 J m2 year1 6. Hydroelectricity produced 1.40818E+16 J year1 (mass) (energy/mass) Mass: 48.11 10000 tons of  SCE 4.81 E11 g of SCE Energy/unit 29270 J g1 SCE Energy 1.40818E+16 J year1 7. Hydro electricity used 1.41491E+16 J year1 (mass) (energy/mass) Production: 48.34 10000 tons of  SCE Mass: 4.83E11 g of SCE Energy/unit 29,270 J g1 SCE 8. Fish production 4.24401E+13 J year1 (mass) (energy/mass) Production: 935,65 tons year1  Mass: 9.3565E10 g of SCE Energy/unit 453.59 J g1  9. Timber production 4.0091E+16E +12 J year1 Forest Harvest 416.66 10,000 m3  Dry wt 0.5 g cm3 Forest mass 2.083E+12 g year1 Energy/unit 19,244 J g1  Agricultural products 1.759E+16 J year1 (annual production mass)(energy/mass) Grain production 1811.1  10,000 tons year1 Mass 1.81 E+13 g year1 Energy/unit 15,900 J g1  2.87965E+17 J year1 Tobacco production 1.6 10,000 tons year1  Mass 1.6 E+10 g year1 Fiber crops Production 1.4 10000ton year1  Mass 1.4E+10 g year1 Energy/unit 16300 J g1  2.282E+14 J year1 Vegetables Production 1577.1 10000 tons year1 Mass 1.577 E+13 g year1  (continued on next page)
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2500 J g1 3.94275E+16 J year1
Livestock (annual production mass)(energy/mass) Meat Production 2,064,531 tons Wt 2.065E12 g Energy/unit 14,000 J g1 Energy 2.89034E+16 J year1 Milk Production: 9,246,619 tons year1 Mass 9.247 E+12 g year1 Energy/unit 2900 J g1 Energy 2.68152E+16 J year1 Poultry eggs Production: 416,889 tons year1 Wt 4.169E11 g Energy/unit 8400 J g1 Energy 3.50187E+15 J year1 Non-renewable sources from within the country 12. Salt 2.4645E+12 g year1 13. Electricity production 6.515E+17 J year1 184.615 billion kW h Energy/unit 360,5397 J/kW h 14. Electricity used 4.183E+17 J year1 116.202 billion kW h Energy/unit 3605397 J/kW h 15. Fertilizer 8.43E+11 g year1 16. Petroleum production 7.00586E+16 J year1 (mass) (energy/mass) Mass 167.38 10,000 tons 1.67 E12 g Energy/unit 41856 J g1 17. Petroleum used 3.52273E+17 J year1 (mass) (energy/mass) Mass 841.63 10,000 tons 8.42E12 g Energy/unit 41,856 J g1 18. Natural gas production 2.74576E+17 J year1 (mass) (energy/mass) Mass 938.08 10,000 tons of SCE 9.38 E12 g of SCE Energy/unit 29,270 J g1 of SCE 19. Natural gas used Mass 353.05 10,000 tons of SCE 3.53E12 g of SCE Energy/unit 29,270 J g1 of SCE Energy 1.03338E+17 J year1 20. Coal used 5.45E+18 J year1 (mass) (energy/mass) Mass: 18531.50 10,000 tons 1.85 E14 g Energy/unit 29,400 J g1 21. Coal production 1.04E+19 J year1 (mass) (energy/mass) Mass: 35437.94 10,000 tons 3.54E14 g Energy/unit 29,400 J g1 22. Calcium carbide 564.46 10,000 T; 5.6446 E+12 g year1 23. Pyritel ore 46.77 10,000 T; 4.67 E +11 g year1
     
24. Crude iron ore
5605.8 10,000 T; 5.61E +13 g year1 25. Aluminum 102.43 10,000 T; 1.02 E +12 g year1 26. Soil erosion total 3.75356E+17 J year1 Agricultural lands 9.73E+16 J year1 (farmed area) (erosion rate) (organic fraction) (energy) Cropland area 713.3 10,000 h Erosion rate 79.90 tons h1 year1 Erosion 5.7E+08 tons year1 Organic fraction 0.03 1E6 g tons1 22604 J g1 Energy 3.87E+17 J year1 Pastureland area 8666.7 10,000 h Erosion rate 18.08 tons h1 year1 Erosion 1.57E+09 tons year1 Organic fraction 0.03 1E6 g tons1 22604 J g1 Energy 1.06E+18 J year1 Imports and outside sources 27. Coal 6.02E+17 J 2047 10,000 tons 29,400 J g1 28. Petroleum 3.33136E+17 J 795.91 10,000 tons 41,856 J g1 29. Metal ores 3.426E+12 g 3,425,996 tons 30. Fertilizers 1.01E+12 g 1,014,256 tons 31. Goods Logs (cu.m) 1.33E+17 J 1.33E+07 m3 Dry wt 0.5 g cm3 Mass 2.083E+12 g year1 Energy/unit 19,244 J g1 Steel 2.50E+10 g 25,000 tons Rubber and related products 3.81E+10 g 381,000 tons Organic chemicals 2.93E+11 g 29.3 10,000 tons 32. Services Emergy of services in all 1.84E+23 sej year1 imported goods Dollar value of imported 4.39E+09 $ year1 goods Emergy to money ratio for 7.53E+12 sej $1 China In 2007 Fuels services 5.29E+09 $ year1 Coal 2047 10,000 tons, 1.33 E9 $ year1 Petroleum 795.91 10,000 tons, 3.96E+09 $ year1 Total value of services 9.67E+09 $ year1 Exports 33. Coal 5.5125E+18 J 18,750 10,000 tons 29,400 J g1 34. Petroleum 5.28558E+16 E+17 J 126.28 10,000 tons 41,856 J g1
  
L.P. Zhu et al. / Acta Ecologica Sinica 32 (2012) 74–88
35. Metal ores 36. Electricity
37. Goods Buchwheat
Glass and its products Ferroalloy Rolled steel Unwrought aluminum Unwrought silver Ferro-silicon Metals of rare-earth and other mixture
1.22E+10 g 1200 tons 2.47309E+17 J 68.59 billion kW h 3,605,397 J kW h 3.22722E+14 J 20,297 tons 15,900 J g1 1.58962E+16 J 805,441 tons 19,736 J g1 1.58962E+16 J 805,441 tons 19736 J g1 1.58962E+16 J 10,473 head 300,000 g/head 12,225 J g1 5.5748E+13 J 3982 tons 14,000 J g1 2.34013E+13 J 1117.86 tons 20934 J g1 1.53309E+14 J 7323.451 tons 20934 J g1 1.22E+10 g 1200 tons 3.78537E+11 g 37,8537 tons 9.56E+11 g 67,310 tons 1,051,000,000 g 1051 tons 125,023,000 g 125.023 tons 307,279,000 g 307,279 tons 1.19E+10 g 11,914 tons
38. Services Emergy of services in all imported goods Dollar value of imported goods Emergy to money ratio for China in 2007 Emergy in the services required for imported goods Fuels services Coal Petroleum Electricity services Pure services Total value of services 39. Tourism Money spent
1.636E+13 sej $1 4.47E+22 sej year1 2.50208E+14 25020.84 10000 tons 1.09728E+14 g year1 10972.78 10000 tons
 Appendix B. References for transformities 
    
A. H.T. Odum, Environmental Accounting: Emergy and Environmental Decision Making, John Wiley & Sons Inc., New York. 1996. B. H.T. Odum, S. Romitelli, R. Tigne, Evaluation Overview of the Cache River and Black Swamp in Arkansas, Center for Environmental Policy, Environmental Engineering Sciences, University of Florida, Gainesville, FL, 1998. C. D.R. Tilley (Ed.), Emergy Basis of Forest Systems, 1999. D. S.L. Brandt-Williams (Ed.), Handbook of Emergy Evaluation. Folio#4. Emergy of Florida Agriculture. Center for Environmental Policy, Environmental Engineering Sciences, University of Florida, Gainesville, FL. 2001 (revised 2002). E. H.T. Odum (Ed.), Emergy and Public Policy. Part I–II, Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL, 1992. F. S.B. Bastianoni, D. Campbell, L. Susani, et al., The solar transformity of oil and petroleum natural gas, Ecological Modelling 186 (2005) 212–220. G. D.E. Campbell, Environmental Accounting Using Emergy: Evaluation of Minnesota, 2009. H. J.B. Zhou, M.M. Jiang, B. Chen, et al., Emergy evaluations for constructed wetland and conventional wastewater treatments. Communications in Nonlinear Science and Numerical Simulation 14 (2009) 1781–1789. I. M.T. Brown, S. Ulgiati, Emergy evaluation of the biosphere and natural capital, Ambio 28 (1999) 486–493.
 Appendix C. References for data 
1.84E+23 sej year1 7.19E+10 $ year1
Emergy to money ratio for inner Mongolia In 2007 Emergy purchased 40. Waste water Mass 41. Solid wastes Mass
7.53E+12 sej $1 1.84E+23 sej year1 5.51E+09 $ year1 18,750 10,000 tons, 1.22E+10 $ year1 126.28 10000 tons, 6.45E+08 $ year1 68.594 billion kW h, 4.64E+09 $ year1 29,750,000 $ year1, 2.24E+20 sej year1 1.96 E10 $ year1
 J. Ming, Z.Z. Liu, et al., The Development and utilization of new energy in inner Mongolia and sustainable development of Chinese energy, Energy Conservation and Environmental Protection 3 (2004) 40-41 (in Chinese).  IMSY, Ed. Inner Mongolia Statistical Yearbook, China Statistical Publishing House, Beijing, 1988–2008 (in Chinese).  I.M.W. Bureau, Bulletin of meteorological disasters of Inner Mongolia in 2009, 2010. (in Chinese) .  CTEI, China’s Yearbook of Ethnic Information, Publishing House of Minority Nationalities, Beijing, 2005, (in Chinese).  Y.Q. Kuang, N.S. Huang, et al. Change of Terrestrial Heat Flow in Ordos Basin since Late Mesozoic and its Effects on the Pattern and Evolution of the Ecologic Environment, Bulletin of Mineralogy, Petrology and Geochemistry 23(4) (2004) 319–325 (in Chinese).  F. Chen, Agricultural Ecology, China Agricultural University Press, Beijing, 2002, (in Chinese).  CSY, China Statistical Yearbook, China Statistical Publishing House, Beijing, 2008 (in Chinese).  Y.F. Hu, J.Y. Liu, et al. Distribution characteristics of 137 Cs in wind-eroded soil profile and its use in estimating wind erosion modulus. Chinese Science Bulletin 50(11) (2005) 1155–1159.
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