• Energy Research

Abstract The integrated model WORLD and Hubbert's model were used for assessment of future supply for different metals: iron, nickel, manganese, chromium, molybdenum, tantalum, niobium, rhenium, zirconium, tungsten, cobalt, copper, zinc, lead, aluminium and the technology metals derived from copper–zinc mining (tellurium, selenium, gallium, indium, antimony, bismuth, tin, germanium, selenium). The connections between their productions were mapped. The literature was reviewed for best estimates of total recoverable amounts, and best estimates were made, considering extraction costs and extractability. Peak years were determined for all the metals studied. Most metals seem to reach peak production during the next 4 decades, suggesting a risk for shortages in the near future. When supplies from mines dwindle, measures such as recycling from society's stock, substitutions to other materials than metals when this is possible, and stopped dissipative uses, will become important mitigation tools, calling for reorganization of resource policies world-wide. Present resource policies at all levels (regional, national, international) are to a large degree inadequate and need thorough review. The relevance of the Hubbert's model as an assessment tool was done. It is useful for all metals taken from independent ore deposits, whereas the method appears to be less suited for extraction of dependent metals unless the curve is derived from the Hubbert's model applied on the parent source. In such times, strategic thinking and strategic leadership based in systems thinking will be required.

AbstractThe authors have collected data for the silver market, shedding light on market size, stocks in society and silver flows in society. The world supply from mining, depletion of the remaining reserves, reducing ore grades, market price and turnover of silver was simulated using the SILVER model developed for this study. The model combines mining, trade markets, price mechanisms, populations dynamics, use in society and waste and recycling into an integrated system. At the same time the degree of sustainability and resource time horizon was estimated using different methods such as: 1: burn-off rates, 2: peak discovery early warning, 3: Hubbert's production model, and 4: System dynamic modelling. The Hubbert's model was run for the period of 6000BC–3000AD, the SILVER system dynamics model was run for the time range 1840–2340. We have estimated that the ultimately recoverable reserves of silver are in the range 2.7–3.1 million tonne silver at present, of which approximately 1.35–1.46 million tonne have already been mined. The timing estimate range for peak silver production is narrow, in the range 2027–2038, with the best estimate in 2034. By 2240, all silver mines will be nearly empty and exhausted. The outputs from all models converge to emphasize the importance of consistent recycling and the avoidance of irreversible losses to make society more sustainable with respect to silver market supply.

This study compares the energy return on investment (EROI) of organic and conventional farms in Iceland. It examines which farming method returns the highest amount of edible energy to society relative to the input required. Twenty farms were studied: two organic and 18 conventional. Real data were gathered directly from five farms (including both of the organic farms in the study). Further data from 15 conventional dairy farms of different sizes were collected from a database maintained by the Icelandic Farmers Association. One of the organic farms studied (Org1) was found to have an EROI of 2.68, whereas two conventional farms used as controls for comparison (Con1-a and Con1-b) had EROIs of 0.60 and 0.69, respectively. The second organic farm (Org2) had an EROI of 0.55, versus the control farm ratio of 0.27. On average, large (<170 hectares) conventional dairy farms had an EROI of 0.65, while medium (<70 hectares) and small (<40 hectares) conventional farms had average EROIs of 0.56 and 0.50, respectively. This limited analysis suggests that organic dairy farms may provide better EROIs than conventional farms, but that their dairy yields per hectare are lower.

The long-term supply sustainability of copper, zinc and lead was assessed. Copper will not run into physcal scarcity in the future, but increased demand and decreased resource quality will cause significant price increases. The copper price is suggested to increase significantly in the coming decades. A similar situation applies for zinc and lead with soft scarcity and increased prices for zinc. The total supply of copper reaches a maximum 2030–2045, zinc 2030–2050 and lead 2025-2030. The copper supply per person and year and decline after 2130, and the copper stock-in-use reaches a maximum in 2050 and decline afterwards. The zinc supply per person per year reach a maximum in 2100 and decline after 2100, and the zinc stock-in use shows a similar pattern. The lead supply per person reach a plateau in 1985, and decline after 2070, whereas the lead stock-in-use reach a plateau in 2080 and decline after 2100. For copper, zinc and lead, scarcity will mainly be manifested as increased metal price, with feedbacks on demand. The predicted price increase will cause recycling to increase in the future. The supply situation for copper would be much improved if the recycling of copper could be strongly promoted through policy means, as well as it would work well to limit the price increases predicted under business-as-usual. Considering the importance of these metals for society, it is essential to set adequate policies for resource efficiency and resource conservation for society.

The world is facing a number of serious problems of which population rise, climate change, soil degradation, water scarcity and food security are among the most important. Aquaponics, as a closed loop system consisting of hydroponics and aquaculture elements, could contribute to addressing these problems. However, there is a lack of quantitative research to support the development of economically feasible aquaponics systems. Although many studies have addressed some scientific aspects, there has been limited focus on commercial implementation. In this review paper, opportunities that have the potential to fill the gap between research and implementation of commercial aquaponic systems have been identified. The analysis shows that aquaponics is capable of being an important driver for the development of integrated food production systems. Arid regions suffering from water stress will particularly benefit from this technology being operated in a commercial environment.

Growth in human population and demand for wealth creates ever-increasing pressure on global soils, leading to soil losses and degradation worldwide. Critical Zone science studies the impact linkages between these pressures, the resulting environmental state of soils, and potential interventions to protect soil and reverse degradation. New research on soil processes is being driven by the scientific hypothesis that soil processes can be described along a life cycle of soil development. This begins with formation of new soil from parent material, development of the soil profile, and potential loss of the developed soil functions and the soil itself under overly intensive anthropogenic land use, thus closing the cycle. Four Critical Zone Observatories in Europe have been selected focusing research at sites that represent key stages along the hypothetical soil life cycle; incipient soil formation, productive use of soil for farming and forestry, and decline of soil due to longstanding intensive agriculture. Initial results from the research show that soil develops important biogeochemical properties on the time scale of decades and that soil carbon and the development of favourable soil structure takes place over similar time scales. A new mathematical model of soil aggregate formation and degradation predicts that set-aside land at the most degraded site studied can develop substantially improved soil structure with the accumulation of soil carbon over a period of several years. Further results demonstrate the rapid dynamics of soil carbon; how quickly it can be lost, and also demonstrate how data from the CZOs can be used to determine parameter values for models at catchment scale. A structure for a new integrated Critical Zone model is proposed that combines process descriptions of carbon and nutrient flows, a simplified description of the soil food web, and reactive transport; all coupled with a dynamic model for soil structure and soil aggregation. This approach is proposed as a methodology to analyse data along the soil life cycle and test how soil processes and rates vary within, and between, the CZOs representing different life cycle stages. In addition, frameworks are discussed that will help to communicate the results of this science into a more policy relevant format using ecosystem service approaches.

Abstract In near future it is essential for human society to switch its primary energy use from finite sources to renewable ones. Ethanol has been claimed to be a potential candidate to replace oil use to great extent. This study illustrates that ethanol production has the potential to rely on organic agriculture and thereby to reduce reliance on fossil fuels. Case studies were carried out by examining three farms (2 conventional, 1 organic) in Austria who are mainly producing sugar beet. We found that organic sugar beet production provided an overall energy return on investment (EROI) of 11.3 whereas the conventional farming practice showed an EROI of 14.1 and 15, respectively. Our study indicates that organic sugar beet production shows potential to substitute conventional industrial sugar beet production to provide inputs to ethanol production. By using organically produced sugar beets as inputs to the ethanol production, fossil fuels can perhaps be avoided to a large extent in the production process, thus, it may be possible to mitigate some of the environmental impacts associated with ethanol production. Larger studies are however needed to better visualise such results.

<p>In this research, we attempt to shed light on the question of where corruption risks in the governance of renewable resources are located and how they have been addressed in European countries that have different levels of corruption. A comparative case study design was chosen, looking into the fisheries sector in Iceland and the forestry sector in Romania. We conducted 25 semi-structured interviews with various stakeholders sampled through a snowball method. Qualitative coding and systems analysis were used to analyse the interviews. The results indicate that comprehensive and ambitious legislation does not necessarily translate into successful resource governance systems. In general, the institutions that were put in place to enforce and monitor the legal codes and regulations did not have the capacity to carry out their role. Additionally, interviewees were generally found to have a widespread perception of there being a corrupt relationship between politics and big companies operating in their sectors. Our findings suggest that when people hold such perceptions, it undermines anti-corruption policy efforts in the resource sectors, which can then impede sustainable resource management.</p>