Resource depletion | EPFL Graph Search

Resource depletion is the consumption of a resource faster than it can be replenished. Natural resources are commonly divided between renewable resources and non-renewable resources (see also mineral resource classification). Use of either of these forms of resources beyond their rate of replacement is considered to be resource depletion. The value of a resource is a direct result of its availability in nature and the cost of extracting the resource, the more a resource is depleted the more the value of the resource increases. There are several types of resource depletion, the most known being: Aquifer depletion, deforestation, mining for fossil fuels and minerals, pollution or contamination of resources, slash-and-burn agricultural practices, soil erosion, and overconsumption, excessive or unnecessary use of resources. Resource depletion is most commonly used in reference to farming, fishing, mining, water usage, and consumption of fossil fuels. Depletion of wild

Towards sufficiency in housing: Agent-based model and transition scenarios

Margarita Agriantoni

Research problem: Housing is responsible for a considerable part of global resource consumption. In Switzerland, it accounts for almost one third of the country's CO2 emissions and half of the total energy demand. Thus, housing plays an important role in the transition to sustainable development. Housing has been thoroughly studied from a disciplinary perspective, e.g., economics, social sciences, psychology, engineering. However, little attention has been paid to housing as a system of interrelated actors, e.g., developers, owners, tenants and state, whose actions might be described by different disciplines. Aim: The aim of this thesis is to investigate how a change in the construction practices of property owners in combination to a more space-efficient allocation of dwellings to households and a behavioural change of tenants can achieve a substantial reduction in the environmental impact of housing. This dissertation focuses on the interrelations of housing actors, concentrating mainly on the property owners and explores which measures and to what extent can lead to a reduction of space consumption of housing.Methods: Housing is characterised by a high level of complexity, therefore a transdisciplinary approach is adopted. Firstly, the Swiss housing market and its unique attributes are studied. However, in this thesis, we study a subset of the Swiss rental housing market; it comprises two housing cooperatives: ABZ in Zurich and SCHL in Lausanne as well as the insurer and asset manager Swiss Mobiliar. Their housing stocks, of approximately 10,000 dwellings, are examined in depth and are used as a case study. Extensive data gathering allowed to create an exhaustive inventory of the building stock of the three property owners. The data on tenants was limited, thus, we conducted a tenant survey. Furthermore, a series of workshops with both tenants and property owners were organised to study their decision-making processes. A bottom-up agent-based model (ABM) is built, which portrays the case study housing system. The main actors of the rental housing market (property owners and households) are represented in the model by agents; the owner agents make decisions about their building stock and tenants, while the household agents choose a dwelling based on their needs and housing preferences. The dynamic evolution of both owners and households and the interaction between them is simulated in the model and allows the study of emergent phenomena. The present thesis attempts the assessment of the environmental impact of housing through the lens of housing sufficiency. Space consumption, in terms of dwelling surface and floor area per capita, is considered as the largest determinant of resource consumption.Results: The simulation results show that measures taken to decrease the environmental impact of housing and space consumption are inadequate if owners do not change their construction practices and households do not actively change their housing behaviour. Most measures explored in this thesis, if implemented individually, succeed in reducing the rate of increase in space consumption but fail to reverse the upward trend. A more space-efficient allocation of dwellings to households proves to have a certain effect. However, only when combined with other measures, such as the densification of the existing building stock and a change in construction practices, a significant decrease of environmental impact is observed.

EPFL2022

Life Cycle Assessment of Thermochemical Conversion of Empty Fruit Bunch of Oil Palm to Bio-Methane

Edgard Gnansounou, Paolo Montafia

The energy demand is increasing as well as the GHG emissions and the fossil fuels depletion. Public awareness on this topic significantly raised up in last decades. Nowadays conversion of residual biomasses in energy represents a real opportunity. However, the sustainability of such fuels has to be proven: Life Cycle Assessment is usually used for that purpose. Because of the increasing natural gas demand, scientists are searching for new gasification techniques and among them the hydrothermal gasification is extremely promising. In this chapter, the LCA of such a technology is presented. Contributions of land use change is highlighted. The chapter evaluates and compares effects of different allocation methods of raw material and it points out a rigorous approach for economic allocation. Furthermore, a section is devoted to the end of the plantation life and its consequence on carbon stock and GHG emissions. When the process is correctly integrated 1 MWh of heat and 16.06 kg of equivalent fertilizer are got by hydrothermal way with a significant reduction of impacts. Moreover, the climate change impact is cut down up to 91% and the fossil depletion decreases up to 96%. The study underlines the great dependency of impact reduction to allocation methods: thus, reduction percentages are 80% GHG emissions and 85% fossil depletion compared to the reference system.

Elsevier2017

Improving slash-and-burn agriculture in Central Menabe, Madagascar

Justine Marie Gay des Combes

Slash-and-burn agriculture is considered as an important driver of deforestation in the tropics. In Madagascar, a biodiversity hotspot, this type of agriculture particularly threatens the tropical forest cover. On the south-western coast of the island, in Central Menabe, the dry tropical forest of Kirindy suffers from an annual deforestation of 2.6%. At such alarming rate, the forest will have entirely disappeared by 2050. The attention of past research programs and conservation actions were mainly on studying the forest or the general interactions between local populations and the forest, with little focus on the slash-and-burn agricultural system itself. Hence, understanding the cultivation practices and assessing alternatives to them is crucial to improve the current forest conservation initiatives. The present thesis answers to the need of an in-depth study of the agricultural practices in Central Menabe. The project aims to (1) analyze the practices of slash-and-burn cultivation in Kirindy forest, (2) explore alternative slash-and-burn practices which may be more sustainable for the forest, (3) determine the implementation perspectives of these alternatives. In a first stage, we have characterized soil productivity along repetitive slash-and-burn cultivation cycles and the farmerâs perception of their agricultural system. Then, we experimented a selective slash-and-burn agriculture (where trees are left intentionally within the cultivated fields), coupled with compost amendment. Finally, we have assessed the implementation potential of that technique through interviews and participating workshops with local farmers. Our findings highlighted that soil depletion due to plant uptake and erosion or leaching by heavy rains, as well as weed invasion were important problems of slash-and-burn cultivation in Central Menabe. Farmers perceive weeding as a work overload. Decrease in grain yield due to slash-and-burn agriculture reaches about 40% after three years of cultivation on the same field (from 4 to 2.5 t ha-1), and decreases up to 75% after a single cyclonic rainy season (from 4 to 1 t ha-1). Further, we demonstrated that combining compost and wood ashes (from the burnings) seems a promising solution to sustain cultivation on the fields. Compost, combined with wood ashes, multiplied corn yield by 5 compared to traditional slash-and-burn agriculture. Growth rates were accelerated and phenology stages of maize plants advanced. Furthermore, this combination also increased soil security by improving the remaining stock of nutrients after a rain simulation. On the other hand, a partial remaining tree cover (selective slash-and-burn agriculture) improved corn yields only when the soil was amended with ashes, not with compost, nor the combination of both. Implementing composting in the forest dwelling communities appears to be a challenging task. Several barriers were highlighted, among them the most important was the water constraints during a consequent period of time related to compost maintenance. Alternative slash-and-burn practices have not been much studied so far because the use of fire was always considered as destructive. Thus, our result will contribute to the development of new forest management strategies which would balance conservation of habitats and rural communities agricultural needs, while minimizing the impact on primary forest.

EPFL2017