Avoiding investment in fossil fuel assets

Reducing greenhouse gas emissions requires a transformation of capital assets in the economy, especially those for energy supply. This paper explores the hypothesis that economically efficient decarbonization occurs when the demand for fossil fuels declines at the same rate as their capital assets depreciate. In theory this means that new investments in fossil fuel assets are avoided, but without incurring stranded assets. We examine the practicality of this hypothesis using a biophysical economic model of the US energy supply system, with an example focused on impacts of electric vehicles on the petroleum supply chain. We specifically address two questions: (1) What rate of market penetration for electric vehicles is necessary to avoid investments in the petroleum-related assets? (2) How do the costs of upstream capital assets change with the transformation to electric vehicles? High annual depreciation rates for oil refineries (δ = 9.47%) and assets for crude oil extraction (δ = 8.23%) have important impacts on results. To avoid new investment in oil refining assets through widespread electrification of light-duty vehicles, the vehicle stock would need to be transformed in just 4 or 5 years. Under most scenarios, some petroleum pipelines will likely become stranded assets due to their low rate of depreciation (δ = 2.48%). In some scenarios, additional investments in wind and solar power generation surpass oil and gas extraction for about 5 years during the transformation to electric vehicles. Once built, however, wind and solar capital assets last longer, as shown by their low rate of depreciation (δ = 3.26%).     

The energy embodied in the first and second industrial revolutions

Understanding the nature of energy embodied in economies is essential to assessing their potential to grow or transform sustainably. As the first country to undergo industrialization, study of the United Kingdom during the Industrial Revolution is particularly important for understanding transformational processes. Historical accounts describe how exploitation of Britain's coal reserves supported the evolution of steel production, railways, and other industries; yet reconstructions of the UK's eighteenth/nineteenth century economy have found relatively small contributions from coal mining to economic growth. Here, economic input‐output models for 1841 and 1907 are used to calculate the coal embodied in capital investment, consumption, and exports. Most of the coal was embodied in consumption in 1841, with coal embodied in exports growing particularly fast by 1907. The coal embodied in capital was smaller, but the energy intensity of investment was about four times larger than the energy intensity of consumption. The coal embodied in building the capital stock, much of it used for production of materials such as iron, steel, and bricks, was important for economic growth and transformation. Using historical proxy data, it is estimated that ～1.1 billion imperial tons of coal (34,000 PJ) were used to build the UK's capital assets between 1760 and 1913. The conceptual model developed here helps to explain the role of energy in economic growth and is important to contemporary sustainable development. This article met the requirements for a gold – gold JIE data openness badge described at http://jie.click/badges .     

The Energy Structure of the Canadian Economy

We developed a model of a national economy in which the phenomena of supply, demand, economic growth, and international trade are represented in terms of energy flows. In examining the structure of the economy, we distinguish between the energy embodied in capital assets used in the production and distribution of energy and that embodied in capital assets and goods that consume energy. Sources used to quantify the energy flows include: end‐use energy data by economic sector; International Energy Agency–style national energy balances, and national input‐output tables. As an example, the Canadian economy for 2008 produced 16.97 exajoules (EJ) of energy, which after net export of 6.16 EJ and other adjustments left a total primary energy consumption of 10.61 EJ. The energy supply and distribution sectors used close to 32% (3.36 EJ) of total primary consumption. Analysis of primary energy consumption shows that 25.14% was embodied in household consumption, 22.85% was consumed directly by households, 7.88% was embodied in government services, and 34.07% was embodied in exports. Of significance to economic growth, 7.14% was embodied in capital in energy demanding sectors, 1.25% in energy consuming personal assets, and 1.52% in supply sector capital. The energy return on energy investment was relatively constant, averaging 5.14 between 1990 and 2008. Capital investments required to decouple the Canadian economy from its dependence on fossil fuels are discerned.     

Current development of biorefinery in China

To meet the demand of its fast growing economy, China has become already the second largest buyer of crude oil. China is facing critical problems of energy shortage and environment deterioration. Rational and efficient energy use and environment protection are both getting more attention in China. Biomass energy is renewable energy made from biological sources. China's biomass resources are abundant, which could provide energy for future social and economic development. However technologies for biomass resource conversion in China are still just beginning. In this paper, current biomass resource distribution and technologies of biomass energy, including power generation, biofuel production and biomass-based chemical production are reviewed.     

Technologies of immortality: the brain on ice

One of the first envatted brains, the most cyborgian element of J. D. Bernal’s 1929 futuristic manifesto, The world, the flesh and the the devil, proposed a technological solution to the dreary certainty of mortality. In Bernal’s scenario the brain is maintained in an ‘out of body’ but ‘like-body’ environment—in a bath of cerebral–spinal fluid held at constant body temperature. In reality, acquiring prospective immortality requires access to very different technologies—those that allow human organs and tissues to be preserved in a quite ‘inhuman’ life-world—the cryogenic storage chamber. Like Bernal, today’s cryonicists consider that immortality can be secured through preservation of the brain alone. In this article I trace attempts to preserve or suspend life, and especially brain function, through the application of new ‘technologies of immortality’. Drawing together historical information on the development of refrigeration, cryopreservation, transplantation, and nanotechnologies, I explore the uneasy relationship between cryonics and the technology on which it depends for its success—cryogenics. In so doing, I argue that the ability to successfully realize the science fiction fantasy of human immortality will rest on a moral and scientific parasitism: the capacity to use the biotechnological artifacts or proxies—cryogenically preserved brains, archived brains, tissues, and immortalized cell lines—derived from the dead, in order to prolong life.     

What Should Be Held Steady in a Steady‐State Economy?: Interpreting Daly's Definition at the National Level

Within this article, I investigate a number of the conceptual issues that arise when attempting to translate Herman Daly's definition of a steady‐state economy (SSE) into a set of national biophysical indicators. Although Daly's definition gives a high‐level view of what would be held steady in an SSE, it also leaves many questions unanswered. How should stocks and flows be aggregated? What is the role of international trade? How should nonrenewable resources be treated? And where does natural capital fit in? To help answer these questions, I relate Daly's definition to key concepts and terminology from material and energy flow accounting. I explore topics such as aggregation, international trade, the relevance of throughput, and hidden flows. I conclude that a set of biophysical accounts for an SSE should include three types of indicators (stocks, flows, and scale), track how stocks and flows are changing over a 5‐ to 10‐year period, use aggregated data that measure the quantity of resource use (rather than its quality), measure both total and nonrenewable resource use, adopt a consumption‐based approach, include hidden flows, and exclude indicators that measure characteristics of the stock of natural capital (with the notable exception of indicators that measure the regenerative and assimilative capacities of ecosystems).     

Energy Return on Investment (EROI) for Forty Global Oilfields Using a Detailed Engineering-Based Model of Oil Production

Studies of the energy return on investment (EROI) for oil production generally rely on aggregated statistics for large regions or countries. In order to better understand the drivers of the energy productivity of oil production, we use a novel approach that applies a detailed field-level engineering model of oil and gas production to estimate energy requirements of drilling, producing, processing, and transporting crude oil. We examine 40 global oilfields, utilizing detailed data for each field from hundreds of technical and scientific data sources. Resulting net energy return (NER) ratios for studied oil fields range from ≈2 to ≈100 MJ crude oil produced per MJ of total fuels consumed. External energy return (EER) ratios, which compare energy produced to energy consumed from external sources, exceed 1000:1 for fields that are largely self-sufficient. The lowest energy returns are found to come from thermally-enhanced oil recovery technologies. Results are generally insensitive to reasonable ranges of assumptions explored in sensitivity analysis. Fields with very large associated gas production are sensitive to assumptions about surface fluids processing due to the shifts in energy consumed under different gas treatment configurations. This model does not currently include energy invested in building oilfield capital equipment (e.g., drilling rigs), nor does it include other indirect energy uses such as labor or services.     

供给侧改革视角下中国省域生态产品有效供给及影响因素

生态产品是事关人类生命健康、经济社会建设的世界性稀缺产品.为了更好地分析生态产品有效供给问题,找出生态产品有效供给的规模效率的变化规律,本研究利用2004—2015年的面板数据,以劳动力、资本、能源和技术为投入变量,以GDP、生态产品和非期望产出为产出变量,运用SBM-Undesirable模型和泰尔指数对我国生态产品有效供给的规模效率及其差异性进行测算,并运用Tobit模型进一步对其影响因素进行实证分析.结果表明: 我国生态产品供给规模效率在2011年以前呈下降趋势,以2012年为转折点呈现上升态势,但地区间仍有较大差距.全国及各地区生态产品有效供给效率的影响因素不尽相同,从全国总体情况看,经济发展水平、产业结构(第二产业增加值占GDP比重)、科技投入、金融资本投入(环境污染治理占GDP比重)、能源消费结构(煤炭消费量占能源消费总量比重)和农业面源污染的影响为负,而生态空间及外贸结构的影响为正;在东部地区,产业结构、科技投入、金融资本、能源消费结构和农业面源污染的影响为负,经济发展水平、生态空间及外贸结构的影响为正;在东北地区,经济发展水平、农业面源污染和外贸结构的影响为负,产业结构、科技投入、能源消费结构和生态空间的影响为正;在中部地区,经济发展水平、科技投入、金融资本、能源消费结构、农业面源污染和生态空间的影响为负,产业结构和外贸结构的影响为正;在西部地区,产业结构、能源消费结构和农业面源污染的影响为负,经济发展水平、科技投入、金融资本、生态空间及外贸结构的影响为正.在进一步对以上实证测算进行理论分析的基础上,从供给侧改革的角度提出有效提高生态产品供给规模效率的政策启示,包括注重转变经济发展方式、优化生态系统结构和遵循生态法则进行整体治理等.     

A process model to estimate biodiesel production costs

'Biodiesel' is the name given to a renewable diesel fuel that is produced from fats and oils. It consists of the simple alkyl esters of fatty acids, most typically the methyl esters. We have developed a computer model to estimate the capital and operating costs of a moderately-sized industrial biodiesel production facility. The major process operations in the plant were continuous-process vegetable oil transesterification, and ester and glycerol recovery. The model was designed using contemporary process simulation software, and current reagent, equipment and supply costs, following current production practices. Crude, degummed soybean oil was specified as the feedstock. Annual production capacity of the plant was set at 37,854,118 l (10 x 10(6)gal). Facility construction costs were calculated to be US dollar 11.3 million. The largest contributors to the equipment cost, accounting for nearly one third of expenditures, were storage tanks to contain a 25 day capacity of feedstock and product. At a value of US dollar 0.52/kg (dollar 0.236/lb) for feedstock soybean oil, a biodiesel production cost of US dollar 0.53/l (dollar 2.00/gal) was predicted. The single greatest contributor to this value was the cost of the oil feedstock, which accounted for 88% of total estimated production costs. An analysis of the dependence of production costs on the cost of the feedstock indicated a direct linear relationship between the two, with a change of US dollar 0.020/l (dollar 0.075/gal) in product cost per US dollar 0.022/kg (dollar 0.01/lb) change in oil cost. Process economics included the recovery of coproduct glycerol generated during biodiesel production, and its sale into the commercial glycerol market as an 80% w/w aqueous solution, which reduced production costs by approximately 6%. The production cost of biodiesel was found to vary inversely and linearly with variations in the market value of glycerol, increasing by US dollar 0.0022/l (dollar 0.0085/gal) for every US dollar 0.022/kg (dollar 0.01/lb) reduction in glycerol value. The model is flexible in that it can be modified to calculate the effects on capital and production costs of changes in feedstock cost, changes in the type of feedstock employed, changes in the value of the glycerol coproduct, and changes in process chemistry and technology.     

Nitrogen and Phosphorus in the Finnish Energy System, 1900–2003

In producing power, humans move the nutrients nitrogen (N) and phosphorus (P) from their long‐term geological and biological stocks and release or emit them in soil, water, and the atmosphere. In Finland, peat combustion is an important driver of N and P fluxes from the environment to human economy. The flows of N and P in the Finnish energy system were quantified with partial substance flow analysis, and the driving forces of emissions of nitrogen oxides (NOx) were analyzed using the ImPACT model. In the year 2000 in Finland, 140,000 tonnes of nitrogen entered the energy system, mainly in peat and hard coal. Combustion released an estimated 66,000 tonnes of N as nitrogen oxides (NOx) and nitrous oxides (N2O) and another 74,000 tonnes as elemental N2. Most of the emissions were borne in traffic. At the same time, 6,000 tonnes of P was estimated to enter the Finnish energy system, mostly in peat and wood. Ash was mainly used in earth construction and disposed in landfills; thus negligible levels of P were recycled back to nature. During the twentieth century, fuel‐borne input of N increased 20‐fold, and of P 8‐fold. In 1900–1950, the increasing use of hard coal slowly boosted N input, whereas wood fuels were the main carrier of P. Since 1970, the fluxes have been on the rise. NOx emissions leveled off in the 1980s, though, and then declined in conjunction with improvements in combustion technologies such as NOx removal (de‐NOx) technologies in energy production and catalytic converters in cars.     

山西省阳泉矿区农户可持续生计研究

矿产资源的开发,在支撑社会经济发展的同时,造成了区域资源和生态环境的改变,极大影响农户的生计方式和生活环境。基于高分辨率遥感影像分析了山西省阳泉矿区典型村庄煤矿开采前后的土地利用变化,基于可持续生计框架（Sustainable Livelihoods Framework,SLF）和参与式农村评估法（Participatory Rural Appraisal,PRA）,研究了矿区农户的生计动态及不同类型失地农户的生计可持续能力。结果表明：1）煤矿开采改变了村庄土地利用格局。耕地大面积减少,由占区域面积69.72%降为29.42%;工矿用地大幅度增加,由占区域面积7.51%增为25.01%;农村建设用地、林地、草地和水域均有不同程度的增加。2）农户的资本组合及生计方式随着煤矿开采呈现相应的动态变化,农户逐渐呈现兼业特性;不同类型失地农户的生计资本存在显著性差异。3）生计资本结构的不同造成农户生计可持续发展能力不平等,生计资本累计值越大,农户的生计可持续性越强。矿区农户生计的研究为促进农户生计资本合理配置、缓解矿区企业与农户利益冲突提供了科学依据。     

Effect of Birth Year on Birth Weight and Obesity in Adulthood: Comparison between Subjects Born Prior to and during the Great Depression in Iceland

Background

Many epidemiological studies have linked small size at birth to adverse adult health outcomes but the relative influence of environmental exposures is less well established.

Methods

The authors investigated the impact of prenatal environmental exposure by comparing 2750 participants born before (1925–1929) and during (1930–1934) the Great Depression in Reykjavik, Iceland. Calendar year served as proxy for environmental effects. Anthropometric measurements at birth and school-age (8–13 years) were collected from national registries. Participants were medically examined as adults (33–65 years).

Results

Mean birth weight, adjusted for maternal age and parity, decreased by 97 g (95% confidence interval (CI): 39, 156) for men and 70 g (95% CI: 11, 129) for women from 1925 to 1934; growth at school-age was significantly reduced for participants growing during the Depression. As adults, women prenatally exposed to the Depression had higher body mass index (Δ0.6 kg/m², 95% CI: 0.2, 1.1), higher fasting blood glucose levels (Δ0.16 mmol/L, 95% CI: 0.07, 0.23) and greater odds of being obese 1.43 (95% CI: 1.01, 2.02) compared to unexposed counterparts. Non-significant associations were observed in men.

Conclusion

Reduction in birth weight due to rapid shifts in the economic environment appears to have a modest but significant association with later obesity for women while male offspring appear to be less affected by these conditions.     

Boom to bust,ashes to (coal) dust: the contested ethics of energy exchanges in a declining US coal market

This essay explores how rank-and-file producers of energy evaluate the ethics of energy exchanges, which sheds light on some of the unexamined assumptions animating anthropological studies of energy and ethics. Exploring how coal miners experience a massive downturn in Wyoming, the centre of US coal production, reveals differing logics of exchange between the producers and consumers of electricity. Most Americans engage with electricity as consumers through a commodity framework, paying utility companies a fee to purchase kilowatt hours that are abstracted from their productive origins. In contrast, the miners experience energy as more of a gift exchange, keeping in view the network of the ultimate consumers of the coal they produce. These differing logics of exchange entail different ethical obligations in the face of the termination of those relationships as the country moves away from coal-fired electricity, helping to explain the outrage that was felt in ‘coal country’ – an outrage that Donald Trump exploited for political purposes during the 2016 US presidential election.     

Obligatory Effort [Hishtadlut] as an Explanatory Model: A Critique of Reproductive Choice and Control

Studies on reproductive technologies often examine women’s reproductive lives in terms of choice and control. Drawing on 48 accounts of procreative experiences of religiously devout Jewish women in Israel and the US, we examine their attitudes, understandings and experiences of pregnancy, reproductive technologies and prenatal testing. We suggest that the concept of hishtadlut—”obligatory effort”—works as an explanatory model that organizes Haredi women’s reproductive careers and their negotiations of reproductive technologies. As an elastic category with negotiable and dynamic boundaries, hishtadlut gives ultra-orthodox Jewish women room for effort without the assumption of control; it allows them to exercise discretion in relation to medical issues without framing their efforts in terms of individual choice. Haredi women hold themselves responsible for making their obligatory effort and not for pregnancy outcomes. We suggest that an alternative paradigm to autonomous choice and control emerges from cosmological orders where reproductive duties constitute “obligatory choices.”     

Dynamic Models of Fixed Capital Stocks and Their Application in Industrial Ecology

Industrial assets or fixed capital stocks are at the core of the transition to a low‐carbon economy. They represent substantial accumulations of capital, bulk materials, and critical metals. Their lifetime determines the potential for material recycling and how fast they can be replaced by new, more efficient facilities. Their efficiency determines the coupling between useful output and energy and material throughput. A sound understanding of the economic and physical properties of fixed capital stocks is essential to anticipating the long‐term environmental and economic consequences of the new energy future. We identify substantial overlap in the way stocks are modeled in national accounting, dynamic material flow analysis, dynamic input‐output (I/O) analysis, and life cycle assessment (LCA) and we merge these concepts into a common framework for modeling fixed capital stocks. We demonstrate the usefulness of the framework for simultaneous accounting of capital and material stocks and for consequential LCA. We apply the framework to design a demand‐driven dynamic I/O model with dynamic capital stocks, and we synthesize both the marginal and attributional matrix of technical coefficients (A‐matrix) from detailed process inventories of fixed assets of different age cohorts and technologies. The stock modeling framework allows researchers to identify and exploit synergies between different model families under the umbrella of socioeconomic metabolism.     

Modeling and Optimization of a Coal‐Chemical Eco‐industrial System in China

China is coal dependent, and this situation will persist for a long time. Because more and more attention has been paid to energy security, the coal‐chemical industry has become a hot topic and has developed quickly. To improve efficiency and reduce emissions, industrial symbiosis (IS) can be introduced when establishing a coal‐chemical eco‐industrial system to achieve harmonious development between nature, industry, and society. In order to learn the influence of IS on the current industrial system, a model of coal‐chemical eco‐industrial systems was built. Using scenario optimization and linear programming, the behaviors and optimal industrial structures of the system under different scenario settings were compared, and industrial ecological analysis was performed. By comparative analysis, results showed that the greatest proportional decrease in the use of coal for coking was 15% compared with actual data for 2005. The resource‐productivity and eco‐productivity were 828 yuan/ton and 2.51, which are much higher than the values of 548 yuan/ton and 1.23 in 2005. The symbiosis index and the link density were found to be 0.675 and 1.67, compared with 0.588 and 0.94 in 2005. Research results showed that the coal‐chemical eco‐industrial system achieved a high value‐added utilization of coal and an updated product profile. Such systems will constitute the main direction and the inevitable trend of China's coal utilization in the future, which will reduce the harm to the environment from increased coal use and benefit the energy industry, the economy, and society.     

Life cycle inventory study of the electrical energy production in Romania

Aim, Scope and Background The paper proposes the assessment of the environmental interventions resulting from the electrical energy production in Romania, a Central East European country, using the LCA technique limited to a Life Cycle Inventory study (an LCA without the Life Cycle Impact Assessment phase). Main Features The following life cycles of the energy carriers employed in the production of the electrical energy are analysed according to their provenance: lignite (domestic) 31.2%, brown coal (domestic) 3.4%, brown coal (import) 0.4%, heavy oil (domestic, land) 4.2%, heavy oil (domestic, continental platform of the Black Sea) 0.4%, heavy oil (import) 3.6%, natural gas (domestic) 12.4%, natural gas (import) 6.1%, hydropower 27.8%, and nuclear energy 10.5% from the total of the electrical energy produced in Romania. The unit processes of the life cycles of these energy carriers are aggregated in two main stages: Pre-combustion (extraction, processing, transport and achievement of infrastructure) and Combustion (the production of electricity). The functional unit of the study is represented by 1 kwh. The spatial limits of the analysed system are extended as far as CIS countries for coal, Western Siberia (Russian Federation) for natural gas and the OPEC countries for oil. The temporal limits are included in the year 2000. Results and Discussion The LCI study enabled us to quantify the interventions on the environment, which result from the electricity production in Romania, the independent use of different energy carriers and the different life cycle stages of the system. The use of the LCA technique in a prospective way shows the reduction of these interventions that could be achieved through the adoption of specific scenarios for the development of electrical energy production in the country. Conclusions The main findings of this Life Cycle Inventory study, the first for Romania, are: the emissions of pollutant substances are prevailing in the combustion stage; for different energy carriers, the magnitude of environmental interventions decrease in the following order: coal, oil, natural gas, hydropower and nuclear energy. By comparison with other countries, the environment is more affected by the production of electricity in the case of Romania and only the promotion of alternative, renewable resources such as hydropower could substantially improve these interventions. Recommendations and Perspectives Some important interactions with the environment, like land use or the risks of the nuclear energy, are not taken into consideration in the study because of the lack of particular data for Romania. We would like to continue the investigation in order to surpass the limits of the study, on the one hand by collecting data concerning the risk of nuclear power or land use at the national level for different energy carriers or, on the other hand, by taking into account some other renewable resources like wind or solar energy.     

Adapting Stand‐Alone Renewable Energy Technologies for the Circular Economy through Eco‐Design and Recycling

Renewable energy (RE) technologies are looked upon favorably to provide for future energy demands and reduce greenhouse gas (GHG) emissions. However, the installation of these technologies requires large quantities of finite material resources. We apply life cycle assessment to 100 years of electricity generation from three stand‐alone RE technologies—solar photovoltaics, run‐of‐river hydro, and wind—to evaluate environmental burden profiles against baseline electricity generation from fossil fuels. We then devised scenarios to incorporate circular economy (CE) improvements targeting hotspots in systems’ life cycle, specifically (1) improved recycling rates for raw materials and (ii) the application of eco‐design. Hydro presented the lowest environmental burdens per kilowatt‐hour of electricity generation compared with other RE technologies, owing to its higher efficiency and longer life spans for main components. Distinct results were observed in the environmental performance of each system based on the consideration of improved recycling rates and eco‐design. CE measures produced similar modest savings in already low GHG emissions burdens for each technology, while eco‐design specifically had the potential to provide significant savings in abiotic resource depletion. Further research to explore the full potential of CE measures for RE technologies will curtail the resource intensity of RE technologies required to mitigate climate change.     

PLUG (Pruning of Local Unrealistic Geometries) removes restrictions on biophysical modeling for protein design

Protein design algorithms must search an enormous conformational space to identify favorable conformations. As a result, those that perform this search with guarantees of accuracy generally start with a conformational pruning step, such as dead-end elimination (DEE). However, the mathematical assumptions of DEE-based pruning algorithms have up to now severely restricted the biophysical model that can feasibly be used in protein design. To lift these restrictions, I propose to prune local unrealistic geometries (PLUG) using a linear programming-based method. PLUG's biophysical model consists only of well-known lower bounds on interatomic distances. PLUG is intended as preprocessing for energy-based protein design calculations, whose biophysical model need not support DEE pruning. Based on 96 test cases, PLUG is at least as effective at pruning as DEE for larger protein designs—the type that most require pruning. When combined with the LUTE protein design algorithm, PLUG greatly facilitates designs that account for continuous entropy, large multistate designs with continuous flexibility, and designs with extensive continuous backbone flexibility and advanced nonpairwise energy functions. Many of these designs are tractable only with PLUG, either for empirical reasons (LUTE's machine learning step achieves an accurate fit only after PLUG pruning), or for theoretical reasons (many energy functions are fundamentally incompatible with DEE).     

The effects of land use and cultural development on the Lake Ontario ecosystem since 1750

Lake Ontario is the lowest in the chain of five Great Lakes which form part of the boundary between Canada and the United States. Although European exploration began as early as 1615, it was not until the mid-18th Century that permanent settlement began in the Great Lakes basin. Construction of the Erie Canal which links Buffalo with New York via the Hudson River, and its branch to Oswego, strengthened ties between settlements around the lower Great Lakes (lakes Erie and Ontario) and rapidly growing populations along the Atlantic seaboard. The coming of railroads greatly expanded these ties, and provided a direct link between Canadian settlements and the port of Montreal. Over the past 200 years, successive waves of immigrants entered the region, particularly from Europe.Cultural development has resulted in a wide range of environmental impacts throughout the Great Lakes basin. Impacts have been particularly severe in Lake Ontario. Major changes in water quality and the structure of biological communities have resulted from forest clearance, agricultural expansion, intensive fishing, industrial and urban development, and lake level control. Introductions of exotic species, inputs of nutrient and toxic contaminants, and the effects of climatic variation and modification of microclimates have all interacted such that it is often impossible to establish singular cause and effect. The effects of cultural impact became most severe during the early 1970s and prompted strong support for the International Great Lakes Water Quality Agreement (1972) between Canada and the United States. In response to this agreement and subsequent revisions, contaminant loadings have been greatly reduced. Present water quality is generally good in Lake Ontario although some persistent toxic substances remain a problem. Programs to restock the lake have also provided major benefits. Although much further work remains, Lake Ontario is undoubtedly a good example of successful large scale remedial actions.