Emergy Analysis of Human Carrying Capacity and Regional Sustainability: an Example Using the State of Maine

The human carrying capacity for a region at a specified standard of living depends on the economic and environmental resources of the region and the exchange of resources across regional boundaries. The length of time that a human population living at a given standard can be sustained depends on the rates of use and renewal of the resource base. All environmental, economic, and social resources are produced as a result of energy transformations; therefore, the energy required for their production can be specified and evaluated in common terms by converting their energy values into emergy. Emergy is defined as the available energy of one kind, previously used up directly and indirectly to make a product or service. Its unit is the emjoule. Emergy values and indices are used to evaluate the resource base for Maine, a politically defined region, and to estimate its human carrying capacity at the 1980 standard of living and for possible future resource bases. Emergy indices for Maine are compared with similar indices for Florida, Texas, and the United States to demonstrate variations in human carrying capacity and sustainability among different regions. The 1980 standard of living for Maine, Florida, Texas, and the Nation as measured by emergy use per person fell within a relatively narrow range of 3.4E16 to 4.3E16 solar emjoules y-1. The human carrying capacity for a region is considered within a pulsing paradigm for sustainability and within the constraints provided by a renewable resource base. For example, in the short-term the developed human carrying capacity for Maine is largely determined by the fuel emergy inflow relative to renewable emergy resources. If purchased emergy inflows relative to Maine's renewable emergy increase to the average ratio for a developed country around 1980, the population living in Maine at 1980 standards could increase to 2.9 million or 2.6 times Maine's 1980 population. In contrast, the human carrying capacity based on Maine's renewable resources alone was 0.37 million people at the 1980 standard of living or 33% of the 1980 population.     

The Ecological Footprint: an Indicator of Progress Toward Regional Sustainability

We define regional sustainability as the continuous support of human quality of life within a region's ecological carrying capacity. To achieve regional sustainability, one must first assess the current situation. That is, indicators of status and progress are required. The ecological footprint is an area-based indicator which quantifies the intensity of human resource use and waste discharge activity in relation to a region's ecological carrying capacity. If the ecological footprint of a human population is greater than the area which it occupies, the population must be doing at least one of the following: receiving resources from elsewhere, disposing of some of its waste outside of the area, or depleting the area's natural capital stocks. To achieve global sustainability, the sum of all regional footprints must not exceed the total area of the biosphere. This paper explains the mechanics of a footprint calculation method for nations and regions. As the method is standardized, the relative ecological load imposed by nations and regions can be compared. Further, a nation's or region's consumption can be contrasted with its local ecological production, providing an indicator of potential vulnerability and contribution to ecological decline.     

Resource Use Rates and Efficiency as Indicators of Regional Sustainability: an Examination of Five Countries

We examine trends from 1970 to the mid 1990's of some variables related to development and sustainability for Costa Rica, Korea, Mexico, the Netherlands and the United States: first, by calculating energy and agricultural efficiencies over time, second, by examining the environmental impacts of economic activities, and third, by estimating ecological footprints. We find that many "optimistic" arguments about sustainability have been misleading, and that there is little or no indication that we are becoming any more sustainable or even efficient. Total quality-corrected energy consumption has increased for all five countries and the renewable energy portion is decreasing. The efficiency of turning energy into both agricultural production and GDP has declined for all countries except for the US. In general, there is a remarkable linearity between resource use and economic and agricultural production over all countries and all years, suggesting severe biophysical constraints to sustainable objectives. On the other hand, per capita ecological footprints have decreased somewhat in Costa Rica, Mexico, and the United States, while national ecological footprints have tended to remain constant except for Korea. While there has been a reduction of specific pollutants in the United States, some of this has been achieved by exporting heavy manufacturing industries. We conclude that continued population and economic growth in each country is likely to make the achievement of any kind of sustainability increasingly unlikely. Sustainability, if that is desirable, requires a very different approach than what we have undertaken to date.     

An Indicator for the Economic Performance and Ecological Sustainability of Nations

This document proposes a new indicator to assess countries’ sustainability. The indicator synthetises measures of economic and ecological efficiency. In other words, we assess the ability of countries to use resources to produce the maximum possible amounts of goods and services while keeping production activities’ impact on the environment as low as possible. The measure of ecological efficiency is the ecological reserve/deficit (ERD), which is based on the concept of ecological footprint. The new indicator is computed using the data envelopment analysis (DEA) model, a well-known non-parametric technique that delivers measures of productive efficiency by comparing outputs to inputs used in production. We modify the standard DEA model in two ways. Firstly, we allow for negative input and output data. Secondly, to increase DEA discriminating power of countries, we compute anti-efficiency measures. This allows us to obtain a ranking of countries based on the best and worst performances. Results show that the new efficiency indicator is valid and that high ERD positively influences the ranking of countries. Introducing anti-efficiency provides more plausible results and a more accurate ranking, for example high-polluting countries like China previously economically efficient are now ranked as low efficient when sustainability is taken into account.

     

Migration of Birds as an Indicator of Broad-Scale Environmental Condition

The general profile of the pollution of drinking water, originating from groundwater, by nitrates, chloride and arsenic, in the Prefecture of Thessaloniki, was studied in this project. Samples (tap water) were collected from 52 areas-villages of the Prefecture, during a period of 6 months. The analytical results were related to certain points on the map of the area, thus producing coloured representations of the Prefecture, according to the concentration of the corresponding pollutant. The statistical analysis of the data led to some conclusions concerning the causes of pollution and the relation of the concentrations to certain physico-chemical parameters. Nitrate concentration of samples collected from two specific regions were especially high, sometimes above the highest permitted level. A limited number of samples (13.5%) contained arsenic concentrations above the imminent EC drinking water limit (10 ppb). The majority of the tap water samples, collected from areas along the seashore contained increased concentrations of chloride ions, which is a clear indication of seawater intrusion into the related aquifers.     

Cadmium Contamination in Wild Birds as an Indicator of Environmental Pollution

Cadmium (Cd) is an environmental pollutant that has serioustoxicity in humans and animals and causes Itai-Itai disease.However, there is little available information on itscontamination in wildlife as an indicator of environmentalpollution. The Cd contents in the kidney and liver of 85 wildbirds from 9 different prefectures in Japan were investigated.The ranges of the Cd contents in the kidney and liver in allbirds were ND-174.4 and ND-21.2 g g^-1 dry wt.,respectively. The mean Cd contents were higher in theoil-contaminated birds than those in the non-contaminated ones.Furthermore, a strong correlation was obtained only between theCd contents in the kidney and those in the liver of theoil-contaminated seabirds and not in the other non-contaminatedones. These results suggest that wild birds reflect the levelof environmental contamination which should be monitored.     

湟水流域土地资源环境承载力分析

以湟水流域为研究区,从生态敏感性、土地利用生态适宜性角度分析流域土地资源利用合理性,以生态用地为约束评价土地资源环境承载能力。结果表明：流域内中度敏感区占比最高,为4170%,主要处于以高、中覆盖度草地、林地、水域及未利用土地为主的浅山区和脑山区的相交区域;高度敏感区占比1513%,集中分布于以林地为主的脑山区。9887%的城乡工矿居民用地处于非敏感区和一般敏感区内,流域内城乡建设用地类型空间布局总体上与生态环境相适应,布局合理;水域、高覆盖度草地和林地的改变会对生态环境造成很大影响,不适宜开发利用。     

关中平原城市群资源环境承载力研究

资源环境承载力评价是实现区域合理规划与可持续发展目标的必要前提。选取2015—2019年11个地级以上城市的面板数据,定量测度关中平原城市群的资源环境承载力,结果表明：关中平原城市群资源环境承载力较弱,仅西安为可载,其余10市均为超载或过载;资源环境承载力存在显著的绝对β收敛、α收敛和空间正相关性;万元GDP工业SO2排放量对资源环境承载力有显著的负向影响,而人均GDP、人均水资源占有量和人均液化石油储气能力均对承载力有显著的正向影响;经济增长对资源环境承载力存在显著的“U”型关系。     

区域污染治理能力与排污规模的协调性评价

为分析区域排污规模与污染治理的协调性,构建了排污规模与污染治理协调度模型,并以2006、2013年的数据对模型进行实证分析。结果表明,制约排污规模和污染治理协调性的主要矛盾是污染治理能力的落后,全国70%以上地区污染治理能力均滞后于污染物产生规模;国内治理能力在研究期间不断提高,区域差异在不断缩小,治理能力过度滞后的省份由14个减少到2个;除江苏外2013年其余各地区均有1项或多项污染物的治理能力滞后,其中生活废水治理能力滞后的区域最多;经济发展水平是影响协调性的重要因素,2013年协调度与地区人均GDP基本呈线性关系。模型实证计算结果与主观判断也较为吻合,具有一定的推广应用价值。     

Sustainability as the key to prioritize investments in public infrastructures

Infrastructure construction, one of the biggest driving forces of the economy nowadays, requires a huge analysis and clear transparency to decide what projects have to be executed with the few resources available. With the aim to provide the public administrations a tool with which they can make their decisions easier, the Sustainability Index of Infrastructure Projects (SIIP) has been defined, with a multi-criteria decision system called MIVES, in order to classify non-uniform investments. This index evaluates, in two inseparable stages, the contribution to the sustainable development of each infrastructure project, analyzing its social, environmental and economic impact. The result of the SIIP allows to decide the order with which projects will be prioritized. The case of study developed proves the adaptability and utility of this tool for the ordinary budget management.