Metallic Mineral Resources in the Twenty-First Century. I. Historical Extraction Trends and Expected Demand

Industrial, technological, and economic developments depend on the availability of metallic raw materials. As a greater fraction of the Earth’s population has become part of developed economies and as developed societies have become more affluent, the demand on metallic mineral resources has increased. Yet metallic minerals are non-renewable natural resources, the supply of which, even if unknown and potentially large, is finite. An analysis of historical extraction trends for eighteen metals, going back to the year 1900, demonstrates that demand of metallic raw materials has increased as a result of both increase in world population and increase in per-capita consumption. These eighteen metals can be arranged into four distinct groups, for each of which it is possible to identify a consistent pattern of per-capita demand as a function of time. These patterns can, in turn, be explained in terms of the industrial and technological applications, and in some cases conventional uses as well, of the metals in each group. Under the assumption that these patterns will continue into the future, and that world population will grow by no more than about 50% by the year 2100, one can estimate the amount of metallic raw materials that will be required to sustain the world’s economy throughout the twenty-first century. From the present until the year 2100, the world can be expected to require about one order of magnitude more metal than the total amount of metal that fueled technological and economic growth between the age of steam and the present day. For most of the metals considered here, this corresponds to 5–10 times the amount of metal contained in proven ore reserves. The two chief driving factors of this expected demand are growth in per-capita consumption and present-day absolute population numbers. World population is already so large that additional population growth makes only a small contribution to the expected future demand of metallic raw materials. It is not known whether or not the amount of metal required to sustain the world’s economy throughout this century exists in exploitable mineral resources. In the accompanying paper, I show that it is nevertheless possible to make statistical inferences about the size distribution of the mineral deposits that will need to be discovered and developed in order to satisfy the expected demand. Those results neither prove nor disprove that the needed resources exist but can be used to improve our understanding of the challenges facing future supply of metallic raw materials.     

Availability of Bauxite Reserves

Based upon a large database, this paper analyzes the record of bauxite mine production, exploration success, and resource depletion and evaluates the availability of bauxite reserves in the near future. The record clearly shows that for the past 50 years world bauxite production rose by an annual increase of over 5% while per capita consumption rose during the same period by about 4%. Time trends of the world bauxite reserve life index (RLI); that is, known world reserves of a given year divided by world production of the same year, are episodic and seem to follow bauxite price cycles. The present-day RLI indicates adequate bauxite supply for about 180 years and is the same as it was in 1950. However, if an annual growth rate of 5% is considered, the currently known reserves will be exhausted within the next 20 years and the reserve base will be adequate for not more than 25 years. This scenario is based, of course, on the unrealistic assumption that future exploration efforts fail to discover additional reserves. Evaluation of the quality, in terms of bauxite signatures, and quantity of presently known bauxite prospects that may be mined in future suggests that there is sufficient potential for adequate bauxite supply for the next 20 to 25 years at least. Bauxite signatures cover a wide range of values that allows selection of the most favorable bauxite prospects for future mining, both in economic as well as environmental terms. Although, there is the general believe that the world abundance of bauxite resources will ensure sufficient supply to meet future demands significant additional reserves have to be discovered if exponential growth rates continue. As the question of future bauxite supply is subject to economic and geologic principles one has to take into consideration that increasing exploration maturity in many mineral provinces will make it difficult to locate additional bauxite reserves and that decreasing real commodity prices will influence the level of investment in bauxite exploration.     

气候变化背景下未来西藏粮食供需平衡状况预测

基于组合预测法、生产函数和笔者前期关于气候变化对西藏粮食产量定量影响的工作,对考虑气候变化影响的未来西藏县（区）级尺度粮食供需平衡状况进行预测。结果表明：① 西藏粮食产量较高的区域集中在一江两河等河谷地带,西藏粮食需求量较大的地区主要在人口较多的县市,未来肉类消费增加将会消耗更多的饲料用粮。② 西藏粮食供需平衡状况南北分异明显,南部河谷地区相对较好,北部羌塘高原较差。③ 当前西藏不能实现考虑口粮、饲料粮、工业用粮、种子用粮和损耗5种需求总和的粮食供需平衡,全区自给率为70.58%,2030年和2050年分别下降至62.59%和53.55%。虽然西藏总需求不能完全自给,但仍能保障口粮自给。④ 气候变化整体上对自给率为正面影响。到2030年和2050年,气候变化将使自治区粮食自给状况提升2.45%和2.09%。研究有助于掌握未来西藏粮食安全状况,规划农业布局,以期保障边疆粮食安全、促进高原农业可持续发展。     

中国耕地与未来30年食物需求、保障及对策

在未来的 30年中 ,中国的人口将继续增长 ,至 2 0 30年达到峰值 1 6亿 ,净增 3亿左右。随着社会经济的发展 ,人民生活水平的提高 ,人均食物需求的量与质越来越高。届时中国食物的保障能力受到国际社会的普遍关注。中国到 2 0 30年 ,满足上述食物需求量 ,食物主要来自耕地的生产潜力和非耕地的食物替代生产两方面。在政策非常强有力、一切从保护耕地出发、严格控制耕地占用和维持动态平衡的条件下 ,到 2 0 30年 ,中国耕地面积可保持 1 31× 1 0 6 hm2。而中国到 2 0 1 0年、 2 0 30年年人均需求粮食分别为 42 0 kg和460 kg,这两个基期年分别需求粮食总量为 5 796× 1 0 8kg和 7360× 1 0 8kg。研究认为 2 0 1 0年、 2 0 30年中国耕地动态变化后食物保障能力分别在 93%和 87%。非耕地资源食物替代是补充食物生产和缓解耕地压力的重要途径。 2 0 30年其食物替代能力可达到 90 0 0 0×1 0 3t,其中草业 3380 0× 1 0 3t,木本粮油 1 70 0 0× 1 0 3t,水域 2 5 82 0× 1 0 3t,野生生物 1 340 0× 1 0 3t,非耕地的事物替代能力达到约 1 0 %。中国食物生产与发展的四个保证 ,一是有效的保护耕地政策 ,二是科学技术进步与科技投入 ,三是构建食物生产体系与保障体系 ,四是高效利用水资源的技术与措施。     

Circuits of scrap: closed loop industrial ecosystems and the geography of US international recyclable material flows 1995–2005

The recycling of scrap material has been identified as an important strategy in the larger theory of industrial ecology. Industrial ecology argues that the traditional model of industrial activity needs to be transformed into a 'closed loop' industrial ecosystem where used materials (scrap) and by-products would substitute for virgin materials during production processes. The recycling of scrap material forms part of this larger effort to reduce the overall environmental impact of production and consumption. A key, but as yet, unresolved question in this process is the geographic scale (local, regional, national, global) at which loop closing should take place. This preliminary empirical research examines the export and import geography of the seven largest (by weight) US scrap commodities (iron and steel, paper, plastics, aluminium, copper, nickel and zinc) between 1995 and 2005 to ascertain the extent to which US scrap flows overseas and how that might affect our understanding of how material loops can close. Other than an integrated export and import relationship with Canada, the results suggest that there are two distinct circuits of scrap flows in the USA. The USA exports a substantial portion of the recyclable scrap generated each year to rapidly developing countries, while importing smaller quantities of scrap from the EU. With the major exception of exporting higher value iron and steel scrap to China, the US tends to export lower value scrap and import higher value scrap. In part this reflects imbalances in the supply and demand for scrap between the USA and the developing world, the lack of potentially available scrap and the absence of a robust recycling infrastructure in the developing world. Although such scrap circuits are probably not ideal, the use of US scrap in the developing world is both a realistic and preferable alternative in the short to medium term than virgin production.     

Phosphate rock demand into the next century: Impact on wolld food supply

A vital and indisputable link exists between phosphate rock and world food supply. Phosphate rock is the source of phosphorus used to make phosphatic fertilizers, essential for growing the food needed by humans in the world today and in the future. We modeled the depletion of the known reserves and reserve base (which includes reserves) of phosphate rock based on various scenarios for increasing population and future demand for phosphate. Using these scenarios, the presently known reserves will be depleted within about 50 years, and the remainder of the reserve base will be depleted within the next 100 years. For this model, we used rates of growth of demand for phosphate rock of between 1 and 1.7 percent annually. We also examined demand rates that decrease over time toward demand stasis. Growthrate scenarios that stabilize demand at the year 2100 are little different from unconstrained growth. Demand stabilization by 2025 extends the reserve base by only about 50 years. Additional considerations could affect these depletion scenarios, causing them to be substantially too high or too low. Nonetheless, the incluctable conclusion in a world of continuing phosphate demand is that society, to extend phosphate rock reserves and reserve base beyond the approximate 100 year depletion date, must find additional reserves and/ or reduce the rate of growth of phosphate demand in the future. Society must: 91) increase the efficiency of use of known resources of easily minable phosphate rock; (2) discover new, economically-minable resources; or (3) develop the technology to economically mine the vast but currently uneconomic resources of phosphate rock that exist in the world. Otherwise, the future availability of present-cost phosphate, and the cost or availability of world food will be compromised, perhaps substantially.     

世界钢铁工业发展趋势及对我国钢铁工业的影响

20世纪是世界钢铁工业快速发展的世纪。在科技进步和市场需求的拉动下,世界钢铁生产的规模、地区格局与原材料供应等都发生了显著变化。进入21世纪,世界钢铁工业将在高科技的推动、原材料供给与产品销售的激烈竞争、以及环境容量的制约下,进入新的结构调整和发展时期。未来世界钢铁工业将以发展中国家的增长为主;生产体制从注重产量向环境友好转化;市场竞争将加速跨国公司全球资本重组。我国钢铁工业在今后20至30年内仍有较大发展空间,国内外市场需求的变化与跨国公司的并购重组,将推动我国钢铁工业布局进一步接近市场,向沿海或大都市周边地区集中。     

基于珠海实证的城市旅游增长极限分析框架

城市旅游是城市的一个开放、高流动的子系统,在一定时期内是相对稳定,有增长极限的。城市旅游增长极限受到供需极限影响,当旅游需求超过供给时,出现过度旅游;而当供给超过需求,就会导致过度旅游化。城市旅游需求增长极限呈现阶梯式,只有当影响城市旅游需求增长的长期因素发生持续重大变化时,城市旅游需求增长才可能突破原有的极限,进入一个新的阶段。城市旅游需求极限规定了城市旅游供给极限,决定了城市在一定时期内适合开发的景区、酒店、餐饮、购物等旅游设施规模。本文基于珠海的实证分析表明,过去十几年,由于旅游供需两方面影响因素缺乏持续重大的变化,城市功能和地位、城市主题和特色等因素相对稳定,加之受到区域其他城市的激烈竞争,珠海中高端旅游需求相对稳定,星级酒店等中高端旅游产品面临增长极限。此时,新增旅游景区和星级酒店并不会带来过夜旅游需求的实质增长,反而可能加剧现阶段旅游供需的失衡,造成过度旅游化。本文也讨论了超越旅游极限的条件以及旅游增长与旅游发展的关系,并进一步建议了旅游统计的改革举措。     

Trends in U.S. Recoverable Coal Supply Estimates and Future Production Outlooks

The geological coal resource of the U.S. is abundant and proved coal reserves are listed as the world’s largest. However, the reserves are unevenly distributed and located in a small number of states, giving them major influence over future production. A long history of coal mining provides detailed time series of production and reserve estimates, which can be used to identify historical trends. In reviewing the historical evolution of coal reserves, one can state that the trend here does not point toward any major increases in available recoverable reserves; rather the opposite is true due to restrictions and increased focus on environmental impacts from coal extraction. Future coal production will not be entirely determined by what is geologically available, but rather by the fraction of that amount that is practically recoverable. Consequently, the historical trend toward reduced recoverable amounts is likely to continue into the future, with even stricter regulations imposed by increased environmental concern. Long-term outlooks can be created in many ways, but ultimately the production must be limited by recoverable volumes since coal is a finite resource. The geologic amounts of coal are of much less importance to future production than the practically recoverable volumes. The geological coal supply might be vast, but the important question is how large the share that can be extracted under present restrictions are and how those restrictions will develop in the future. Production limitations might therefore appear much sooner than previously expected.     

非洲在世界石油供给格局中的地位演变

21世纪以来,非洲已成为世界石油进口大国寻求来源地多元化、保障自身石油安全的战略高地,也成为我国的第二大石油来源地。考察非洲在世界石油供给格局中的地位及演变,有利于系统把握非洲石油供给的优劣势,为优化我国对非石油合作战略提供依据。本文以国家为研究单元,综合运用箱线图和空间聚类分析法,创新份额和位序综合分析法,对比考察了...     

中国能源供需EMD分析及动力学预测

根据我国能源总供给和总需求的统计数据,运用EMD方法对我国能源供需情况进行多尺度分析,构建带有周期波动的中国能源供需动力学模型,揭示其动力特征,进行数值模拟并提出虚拟能源理论。研究结果表明:到2020年我国能源生产量为35.6亿t标准煤,能源消费量为42.93亿t标准煤,供需缺口达7.33亿t标准煤,可见我国能源消费速度远远大于能源生产速度。我国未来的能源安全问题十分严峻。     

全球变化对中国粮食安全的影响分析

以斯德哥尔摩环境研究所(SEI)建立的粮食需求和供应模型为基础,同时采用Ds和Shaw建立的全球变化各因子对粮食需求和供给影响的模型对其变量进行修正,结合唐国平、李秀彬的结果,模拟计算了全球变化条件下,我国未来粮食需求量和产量。在分析中发现:受全球变化的影响,在保持人民消费水平持续增长的条件下我国未来粮食生产有可能不能满足需求增长的要求,存在7～8%的粮食缺口。但是,由于全球变化的各个因素都存在很大的不确定性,而且技术进步对增加粮食产量有很大促进作用。计算结果揭示,只要采取正确的措施来尽量减少全球变化带来的不利影响,危机是可以避免的     

基于产业链的全球铜贸易网络结构研究

基于产业链视角研究铜贸易网络,构建了2017年铜矿石、粗铜、精炼铜、铜材和废杂铜5类含铜产品的全球贸易网络,对比产业链上各环节产品的贸易网络的拓扑结构,以全面刻画铜资源的全球流动以及国家（地区）之间的铜贸易关系。主要结论如下：① 2001年以来,全球含铜产品贸易重量稳定增长,其中铜矿石贸易重量最大,精炼铜次之。② 5类含铜产品贸易网络的拓扑结构存在明显差异,根据社区发现算法可划分为4~8个组团,模块度在0.216~0.482之间。由于资源禀赋和工业体系发展程度不同,大部分国家（地区）在5类贸易网络中分属于不同的组团。③ 中国对铜资源的需求巨大,围绕着中国的需求产生的贸易关系在铜矿石、粗铜、精炼铜、废杂铜4类贸易网络中都构成第一大组团,分别包含47、102、120、135个国家（地区）,表明中国在全球铜贸易中占有重要地位,但也反映了中国铜资源自给率低、对外依存度大等问题。     

中国粮食生产的综合影响因素分析

采用模型模拟的方式, 根据中国社会发展规划, 将未来社会经济发展情景与区域气候模型、水资源模型和作物模型相连接, 综合评估和分析未来中国的粮食生产状况, 以期为宏观决策提供科学参考。结果表明, ①气候变化将影响未来三大作物单产, 如果不考虑 CO₂ 肥效作用, 未来雨养作物单产将受到更大冲击; 当灌溉条件保障后, 水稻受到冲击更大, 单产降低最多, 尤其是 A2 情景。如果考虑 CO₂ 肥效作用, 未来玉米平均单产变化不大, 小麦单产明显增加, 尤其是雨养小麦, 水稻单产也有所增加。②未来气候变化、水资源、社会经济发展将影响中国三大作物的需水量和农业供水量, 导致水稻、灌溉玉米和小麦的播种面积下降, 而雨养小麦和玉米的播种面积上升。③未来气候变化、 CO₂ 肥效、水资源和土地利用变化对粮食生产的影响较为复杂, 依情景和时段的不同而不同。农业可用水资源对粮食总产的影响最不利, 致使三大作物粮食总产量明显降低, 成为未来粮食生产的主要限制因素, 尤其是水稻生产; 土地利用对总产的负面影响最小; 气候变化和 CO₂ 的相互作用可使总量少许增加。未来各情景下水稻受到冲击最大, 而小麦和玉米则表现为不同程度的增产。     

The Evolution of Giant Oil Field Production Behavior

The giant oil fields of the world are only a small fraction of the total number of fields, but their importance is huge. Over 50% of the world’s oil production came from giants by 2005 and more than half of the world’s ultimate reserves are found in giants. Based on this, it is reasonable to assume that the future development of the giant oil fields will have a significant impact on the world oil supply. In order to better understand the giant fields and their future behavior, one must first understand their history. This study has used a comprehensive database on giant oil fields in order to determine their typical parameters, such as the average decline rate and life-times of giants. The evolution of giant oil field behavior has been investigated to better understand future behavior. One conclusion is that new technology and production methods have generally led to high depletion rates and rapid decline. The historical trend points towards high decline rates of fields currently on plateau production. The peak production generally occurs before half the ultimate reserves have been produced in giant oil fields. A strong correlation between depletion-at-peak and average decline rate is also found, verifying that high depletion rate leads to rapid decline. Our result also implies that depletion analysis can be used to rule out unrealistic production expectations from a known reserve, or to connect an estimated production level to a needed reserve base.     

SPECIALTY CROPLAND IN CALIFORNIA*

ABSTRACT. Census data do not support the widespread popular perception that urban encroachment on cropland in California is serious enough to justify programs of farmland preservation. Between 1949 and 1997 the acreage of harvested cropland declined near Los Angeles, in the San Francisco Bay area, and near Sacramento, but the high‐value specialty agricultural production displaced from these areas has been relocated to more distant areas, where it has replaced lower‐value field crops, and specialized agricultural production has increased steadily in the state. Vegetable production in the Salinas Valley and dairying near Los Angeles illustrate the twin processes of relocation and replacement. Urban encroachment actually has been a boon to California agriculture, because it has transferred massive amounts of urban capital to cash‐strapped farmers and enabled them to develop efficient modern operations. Much of the concern about loss of farmland really is concern about loss of open space and amenities, and urban demand for water probably will be a greater constraint on California agriculture than will urban demand for land.     

Employment Trends in Geography,Part 1: Enrollment and Degree Patterns*

This paper is the first in a series of three papers dealing with the current and future labor market for geographers. It is based on a report prepared by the Association of American Geographers' (AAG) Employment Forecasting Committee to the National Research Council's (NRC) Rediscovering Geography Committee. This report provides a data-based analysis of the past and future supply of geographers, the current labor market conditions in the field, and the factors likely to influence the future demand for geographers (faculty hiring, geographic education initiatives, trends in private-sector jobs, etc.). Each year some 4,000 individuals receive degrees in geography from America's institutions of higher education. They, or some portion of them, make up the new supply of geographers entering the labor market. In the near future (up to five years), the availability of new geographers is related to the number of geography students now in the educational pipeline. Their current specialties, and the specialties of the programs from which they come, tell us about the types of skills and the kinds of interests to be held by future labor force entrants. In the longer term (five to ten years), the number of new geographers will be influenced by geographic education initiatives at the precollegiate level. More and better geographic instruction in elementary and secondary schools will expose more students to geography as a field of study and as a potential career path. The purposes of this paper are to (1) review degree and enrollment trends in geography, (2) assess the “trickle-up” effects of geographic education initiatives at the precollegiate level, and (3) investigate the characteristics of future supply as evidenced by the types of occupations for which geography departments are now preparing students.     

我国矿产资源可持续利用对策

矿产资源是不可再生的稀缺资源。本文综述了我国33种主要矿产的供需现状，通过对主要矿产90年代初静态保证年限与2010年预测需求保证年限计算结果对比分析，认为未来30—50年内我国矿产资源中对经济建设起重要作用的部分大宗矿产面临的短缺问题较为严重，必须尽快寻找和采取有效的可持续利用对策，并分类提出和论述了我国能源矿产、金属矿产及非金属矿产实现可持续利用应采取的基本对策。     

全球锂资源综合评述

发展高效清洁能源是解决能源和环境问题的有效途径,交通电力化和能源储存使全球对锂产品的需求持续快速增加,导致全球对锂资源越来越关注。然而,不同文献报道和不同信息来源的全球锂资源量差别较大,我们在对各种最新报道和公开的信息进行系统分析的基础上,对全球锂资源进行了综合评述。全球卤水锂和矿石锂资源总量为3 190～5 190万吨(以金属锂计),卤水锂和矿石锂分别约占62.6%和37.4%,全球70%以上的卤水锂资源在智利、阿根廷、玻利维亚锂三角地区。以卤水为原料生产锂盐能耗低、成本低,对卤水锂资源会越来越关注,卤水提锂将成为未来锂资源提取的重要方向。     

Quantitative assessment of future development of cooper/silver resources in the Kootenai National Forest,Idaho/Montana: Part I—Estimation of the copper and silver endowments

Faced with an ever-increasing diversity of demand for the use of public lands, managers and planners are turning more often to a multiple-use approach to meet those demands. This approach requires the uses to be mutually compatible and to utilize the more valuable attributes or resource values of the land. Therefore, it is imperative that planners be provided with all available information on attribute and resource values in a timely fashion and in a format that facilitates a comparative evaluation.The Kootenai National Forest administration enlisted the U.S. Geological Survey and U.S. Bureau of Mines to perform a quantitative assessment of future copper/silver production potential within the forest from sediment-hosted copper deposits in the Revett Formation that are similar to those being mined at the Troy Mine near Spar Lake. The U.S. Geological Survey employed a quantitative assessment technique that compared the favorable host terrane in the Kootenai area with worldwide examples of known sediment-hosted copper deposits. The assessment produced probabilistic estimates of the number of undiscovered deposits that may be present in the area and of the copper and silver endowment that might be contained in them.Results of the assessment suggest that the copper/silver deposit potential is highest in the southwestern one-third of the forest. In this area there is an estimated 50 percent probability of at least 50 additional deposits occurring mostly within approximately 260,000 acres where the Revett Formation is thought to be present in the subsurface at depths of less than 1,500 meters. A Monte Carlo type simulation using data on the grade and tonnage characteristics of other known silver-rich, sediment-hosted copper deposits predicts a 50 percent probability that these undiscovered deposits will contain at least 19 million tonnes of copper and 100,000 tonnes of silver. Combined with endowments estimated for identified, but not thoroughly explored deposits, and deposits that might also occur in the remaining area of the forest, the endowment potential increases to 23 million tonnes of copper and 190,000 tonnes of silver.