No / The emission of greenhouse gases on a global scale is predominantly caused by the utilization of fossil fuels. Various methods have been explored to address the recycling of CO2, which among, the CO2 conversion into high-value chemicals become so promising. The purpose of this book chapter evaluation is CO2 reduction and H2 evolution reactions for producing syngas. A comprehensive analysis shall highlight (i) the technical advantages and impediments of various reactor classifications, (ii) the effect of electrolytes on electrolyzers in the liquid phase, and (iv) the catalysts that are viable for the creation of important products such as CO.

No

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

The aim of this study was to determine a carbon and water footprint for a beverage manufacturing company. The carbon footprint determination was conducted on Scope 1 and Scope 2. The water footprint was determined on the blue water and grey water. The beverage production volumes of the beverage manufacturing company were used to determine both the carbon and the water footprint. The theoretical background to this study was based on both local and international beverage companies and the outcome for the carbon and water footprint was benchmarked against the local and international companies. The objectives of this study were achieved by calculating a carbon and water footprint for the beverage company. The carbon footprint unit of measure is g CO2e / litre produced and the water footprint is litre water/litre produced. The unit of measure for pollutant grey water footprint is measured in milligram. Based on the results achieved in this study, recommendations for carbon and water footprint reductions were made to the beverage company. Reduction targets for production year 2020 were also recommended based on the implementation of the reduction plans. / Environmental Sciences / M. Sc. (Environmental Science)

The aim of this thesis is to examine the nature and characteristics of tropospheric ozone over Johannesburg, South Africa. Ozone, water vapour and meteorological profile data, which form part of the MOZAIC (Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft) database for the period 1995 to 2000 were utilized in this study. The thesis is divided into two main parts. The first part deals with the computation of total tropospheric ozone. A clear seasonal cycle, with ozone peaking in September and October is found. It is suggested that the main reason for the spring maximum is biomass burning, combined with prevailing anticyclonic circulation patterns, which facilitate the build-up of ozone over the region. Variability in TTO is greatest in January, September and November and least during autumn and winter (April to July). The lower day-to-day variability in autumn and winter is a reflection of the more settled weather at this time. Interannual variability is least in January and April to June. The autumn and winter ozone values are more consistent and appear to represent background tropospheric ozone loadings on which the dynamic and photochemical influences of other months are superimposed. High TTO events (>30 DU) occurred predominantly during September and October. Enhancements in the lower troposphere occurred mostly in September and seldom lasted for more than 1-2 consecutive days. It is suggested that these events are most likely due to effects of local surface pollution sources, either localised biomass burning or urban-industrial effects. An extended period of enhancement in the 7-12 km layer occurred from 14-17 September 1998 and again on 20 September 1998. The extended duration of this event suggests that it is due to an STE event. Confirmation of this was given in a case study of a particular MOZAIC flight on 16 September 1998 from Johannesburg to Cape Town. The second part of the thesis deals with the classification of ozone profiles and is used to find pattern and order within the profiles. TWINSPAN (Two-Way INdicator SPecies ANalysis), a cluster analysis technique, was used to classify the profiles according to the magnitude and altitude of ozone concentration. Six distinct groups of profiles have been identified and their characteristics described. The HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) trajectory model was used to relate the profiles to the origin of air masses, revealing clearly defined source regions. The mid-tropospheric peak in summer and the low to mid-tropospheric enhancement in spring is attributed to continental areas over central Africa and long-range transport while local sources are responsible for the winter low tropospheric enhancement. Reduced ozone values are due to westerlies bringing in clean maritime air. The classification has highlighted three important findings. Firstly, it has emphasized the pronounced seasonality of ozone profiles. It is evident that seasons are dominated by particular patterns and by inference, the processes and transport patterns that shape individual profiles are seasonally dependent. Secondly, the widely recognized spring maximum in tropospheric ozone has been confirmed in this classification, but a new and equally high summer mid-tropospheric enhancement due to the penetration of tropical air masses from continental regions in central Africa has been identified. Thirdly, it is suggested that the computation of a mean profile and furthermore, extrapolation of trends based on a mean profile is meaningless, particularly for a location on the boundaries of zonally defined meteorological regimes. / Thesis (M.A.)-University of Natal, Durban, 2002.

O Painel Intergovernamental de Mudanças Climáticas da ONU (IPCC) tem comprovado com nível de confiança cada vez maior, ao longo dos últimos anos, a forte relação entre o aumento da temperatura média global e o aumento dos gases de efeito estufa (GEEs) principalmente quanto ao gás que mais contribui para a composição desses gases: o gás carbônico ou CO2. O Brasil se insere no rol dos emissores desse gás, principalmente devido ao desmatamento das reservas florestais que possui. Assim, assumiu o compromisso na Convenção Quadro das Nações Unidas sobre Mudanças Climáticas (United Nations Framework Convention on Climate Change UNFCCC) de estabilizar suas emissões e inventariar periodicamente os seus GEEs. Dentro deste contexto, cabe também à indústria levantar sua parcela de responsabilidade significativa neste processo ameaçador para a vida no planeta terra. Desta forma, o principal objetivo do presente trabalho foi o de levantar e contabilizar o Inventário dos GEEs emitidos em 2006 por uma empresa que produz importantes insumos para a indústria de petróleo. A pesquisa bibliográfica sobre a metodologia mais adequada e sua aplicação para a empresa em estudo foram os principais objetivos específicos. A autora não encontrou fatores de emissão de CO2 (kg CO2/TJ do combustível, detalhado no decorrer deste trabalho) desenvolvidos no Brasil para levantar o inventário, com um nível razoável de confiança, que reflita a situação real e local. Toda a pesquisa bibliográfica feita mostrou que os trabalhos realizados mesmo por órgãos governamentais brasileiros usaram a metodologia do IPCC (versão anterior à usada neste trabalho) que foi elaborada por países desenvolvidos, que não é o nosso caso ou realidade. Foram feitas diversas visitas à empresa, levantadas todas as fontes potenciais de emissão, consumos e características de todos os combustíveis usados, bem como o levantamento do trabalho desenvolvido sobre geração de mudas de plantas no seu horto. Através de cálculos por essa metodologia reconhecida mundialmente (IPCC) a autora encontrou um valor em torno de 76.000 toneladas de CO2 emitidos pela empresa em 2006. A empresa neutralizou cerca de 80 toneladas de CO2, através da produção de mudas (para doação e plantio em torno de uma área que é um passivo ambiental) em seu horto e o que plantou na área desse passivo em 2006. Isso significou cerca de 0,1% do que emitiu / The Intergovernamental Panel Climate Change - IPCC from ONU has proved with higher level of confidence, along last years, a strong relation between the global average temperature increasing and the Greenhouse Gases increasing mainly about the biggest contributor to the composition in these gases: the carbonic gas or CO2. Brazil is included in the list of these gas polluters, mainly because of its deforestation. Then, it assumed the commitment with United Nations Framework Convention on Climate Change UNFCCC of stabilize and calculate his Greenhouse Gases (GHG) Inventory. In this context, the industries must to survey their part of responsibility in this threatening process for the life in this planet. For the reasons above, the main purpose from the present work is to calculate the Greenhouse Gases emissions inventory in 2006 from a enterprise that produces important inputs for a petroleum industry. The specific purposes were to research the bibliography about the most suitable methodology and its application for this enterprise. The author of this work didnt find any emission factors for CO2 developed in Brazil for calculate the inventory, with a reasonable level of confidence, which can show the real and local situation about this subject. Then, the entire bibliographic search done showed that the works found even in governmental institutions used the IPCC methodology, done by developed countries, that isnt our reality. For this study, it was done several visits to that enterprise and identified all the sources from these GHG, fuel uses and their quantities and intensive bibliographic searches about several national and international methodologies. It was seen the developed work done by this enterprise about generation of seedling (plants) in its market garden. It was chosen the IPCC methodology that was the tool to calculate about 76.000 t of CO2 emitted by the enterprise in 2006. This studied enterprise neutralized 80 t of CO2, through the production of plants cuttings (for donation to people and to plant in around an area that is an environmental passive) in its market garden and what it planted in that passive area in 2006. This was about 0,1% on that it emitted

O Painel Intergovernamental de Mudanças Climáticas da ONU (IPCC) tem comprovado com nível de confiança cada vez maior, ao longo dos últimos anos, a forte relação entre o aumento da temperatura média global e o aumento dos gases de efeito estufa (GEEs) principalmente quanto ao gás que mais contribui para a composição desses gases: o gás carbônico ou CO2. O Brasil se insere no rol dos emissores desse gás, principalmente devido ao desmatamento das reservas florestais que possui. Assim, assumiu o compromisso na Convenção Quadro das Nações Unidas sobre Mudanças Climáticas (United Nations Framework Convention on Climate Change UNFCCC) de estabilizar suas emissões e inventariar periodicamente os seus GEEs. Dentro deste contexto, cabe também à indústria levantar sua parcela de responsabilidade significativa neste processo ameaçador para a vida no planeta terra. Desta forma, o principal objetivo do presente trabalho foi o de levantar e contabilizar o Inventário dos GEEs emitidos em 2006 por uma empresa que produz importantes insumos para a indústria de petróleo. A pesquisa bibliográfica sobre a metodologia mais adequada e sua aplicação para a empresa em estudo foram os principais objetivos específicos. A autora não encontrou fatores de emissão de CO2 (kg CO2/TJ do combustível, detalhado no decorrer deste trabalho) desenvolvidos no Brasil para levantar o inventário, com um nível razoável de confiança, que reflita a situação real e local. Toda a pesquisa bibliográfica feita mostrou que os trabalhos realizados mesmo por órgãos governamentais brasileiros usaram a metodologia do IPCC (versão anterior à usada neste trabalho) que foi elaborada por países desenvolvidos, que não é o nosso caso ou realidade. Foram feitas diversas visitas à empresa, levantadas todas as fontes potenciais de emissão, consumos e características de todos os combustíveis usados, bem como o levantamento do trabalho desenvolvido sobre geração de mudas de plantas no seu horto. Através de cálculos por essa metodologia reconhecida mundialmente (IPCC) a autora encontrou um valor em torno de 76.000 toneladas de CO2 emitidos pela empresa em 2006. A empresa neutralizou cerca de 80 toneladas de CO2, através da produção de mudas (para doação e plantio em torno de uma área que é um passivo ambiental) em seu horto e o que plantou na área desse passivo em 2006. Isso significou cerca de 0,1% do que emitiu / The Intergovernamental Panel Climate Change - IPCC from ONU has proved with higher level of confidence, along last years, a strong relation between the global average temperature increasing and the Greenhouse Gases increasing mainly about the biggest contributor to the composition in these gases: the carbonic gas or CO2. Brazil is included in the list of these gas polluters, mainly because of its deforestation. Then, it assumed the commitment with United Nations Framework Convention on Climate Change UNFCCC of stabilize and calculate his Greenhouse Gases (GHG) Inventory. In this context, the industries must to survey their part of responsibility in this threatening process for the life in this planet. For the reasons above, the main purpose from the present work is to calculate the Greenhouse Gases emissions inventory in 2006 from a enterprise that produces important inputs for a petroleum industry. The specific purposes were to research the bibliography about the most suitable methodology and its application for this enterprise. The author of this work didnt find any emission factors for CO2 developed in Brazil for calculate the inventory, with a reasonable level of confidence, which can show the real and local situation about this subject. Then, the entire bibliographic search done showed that the works found even in governmental institutions used the IPCC methodology, done by developed countries, that isnt our reality. For this study, it was done several visits to that enterprise and identified all the sources from these GHG, fuel uses and their quantities and intensive bibliographic searches about several national and international methodologies. It was seen the developed work done by this enterprise about generation of seedling (plants) in its market garden. It was chosen the IPCC methodology that was the tool to calculate about 76.000 t of CO2 emitted by the enterprise in 2006. This studied enterprise neutralized 80 t of CO2, through the production of plants cuttings (for donation to people and to plant in around an area that is an environmental passive) in its market garden and what it planted in that passive area in 2006. This was about 0,1% on that it emitted

MESHWR / Department of Hydrology and Water Resources / Greenhouse gases (GHGs) from coal power station affect the behaviour of climatic parameters such as the temperature, rainfall and evaporation, over a long period of time, hence causing climatic trends. This study focused on investigating the impacts of Greenhouse gases (GHGs) from coal power stations on climatic and hydrological trends in Witbank area. To accomplish this, linear regression (LR) and Mann-Kendall (MK) trend test were used to detect the hydro-climatic trends and their significance. GHG emissions were obtained from Eskom’s sustainability report on the Eskom website. Temperature data for the years 1950- 2000 and 1993-2016 and rainfall data for the years 1925-2000 and 1993-2016 were used. Double Mass Analysis (DMA) was used to check the homogeneity and consistency of temperature and rainfall data from South African Weather Services (SAWS) station with the Lynch database and Water Research Commission (WRC) data. Data was patched and extended using LR where necessary. Trends in temperature, precipitation and flow were assessed using MK trend test and LR based on monthly, seasonal, and annual scales. GHG emissions were compared with the hydro-climatic data over time in order to detect the impacts of GHG emissions on temperature, rainfall and streamflow. The MK results indicated that GHG emissions had some impacts on temperature with statistically significant increase in annual, monthly and seasonal time scales for the period 1950-2016. LR also produced the same results for annual temperature. Monthly and seasonal temperature could not be produced with the LR method because of data gaps. The MK and LR models produced similar results, indicating that there was a non-significant increase in temperature before coal power stations were introduced (1950-1974) and a significant increase in temperature after the commissioning of coal power stations (1975-2016). MK and LR also produced the same results for annual rainfall data, indicating that there was a significant increase in rainfall before coal power stations were introduced (1925-1974) and a non-significant increase after the commissioning of coal power stations (1975-2016). For monthly time scales MK and LR indicated increasing and decreasing trends before and after coal power stations were introduced. MK and LR results for streamflow stations B2H004 and B2H007 showed similar results indicating non-significant increase in annual and seasonal streamflow, but differed in monthly streamflow where MK showed significant increases whilst LR showed non-significant trends. The study concluded that GHGs from coal power stations had significant impacts on the hydro-climatic trends in Witbank area. GHGs from coal power stations caused significant increase in temperature as temperature increased by 3.7°C after coal power stations were introduced, whereas temperature had increased by 1.7 °C. It is recommened that more research should be done on alternative sources of energy such as wind and solar energy to check their suitability and applicability in South Africa. / NRF

Master of Science / Department of Chemical Engineering / Larry E. Erickson / The impact of human activities on the atmosphere and the accompanying risks of long-term global climate change are by now familiar topics to many people. Although most of the increase in greenhouse gas (GHG) concentrations is due to carbon dioxide (CO2) emissions from fossil fuels, globally about one-third of the total human-induced warming effect due to GHGs comes from agriculture and land-use. This report provides a brief review of greenhouse effects and impacts on climate, human health and environment. The sources of emissions of greenhouse gases due to human activities, both current estimates and future projections, have been included. The report further discusses possible options for mitigation of greenhouse gases. The report also discusses the role agriculture can play towards mitigation of greenhouse gases as many agricultural processes such as anaerobic digestion, manure gasification; carbon sequestration etc. can help reduce or offset greenhouse gas emissions. Capture and sequestration of CO2 released as a result of burning fossil fuel in power plants, energy and other industries is gaining widespread interest as a potential method of controlling greenhouse gas emissions. Various technologies such as amine (MEA)-based CO2 absorption system for post-combustion flue gas applications have been developed, and can be integrated with existing plant operations. Removal of SO2 by using amine-based carbon capture system offers additional benefit. Efforts are underway to develop a broader suite of carbon capture and sequestration technologies for more comprehensive assessments in the context of multi-pollutant environmental management. Geologic formations and/ or possibly oceans can be used as sinks to store recovered CO2. In oil and gas exploration industry CO2 may be injected in producing or abandoned reservoirs which will not only help in maintaining the reservoir pressure (which improves overall field exploitation) but in some cases even leads to enhanced oil recovery.

Reducing anthropogenic GHG emissions globally is a key driver for the development of renewable energy sources. A key route towards achieving this is to replace fossil-based fuels with renewable and low carbon energy technologies such as biofuels from energy crops. Cereals and oil-seed crops such as corn, wheat, and soybean are the main feedstocks primarily used for biofuels production and the key characteristics of these crops are high biomass and energy yield per ha. However, there are concerns about the availability and sustainability of these crops for biofuels production in the face of a changing climate since crop productivity is inherently sensitive to climate. Therefore, an understanding of the impacts of climate change on energy crops production as feedstocks for biofuels production and their potential for life cycle GHG emissions reductions is crucial for making decisions on future biofuels production. This thesis examined potential climate change impacts on the productivity of two major biofuel crops: corn (Zea mays L.) and soybean (Glycine max) in Gainesville, USA and one major biofuel crop: wheat (Triticum spp.) in Rothamsted, UK. The overall objective was to calculate the potential impacts of combined changes in climate variables: surface air temperature (T), precipitation (P), and atmospheric concentration of CO2 ([CO2]) on life cycle GHG emissions savings of biofuels from corn, soybean, and wheat. The methodology was underpinned by life cycle thinking. Life cycle assessment (LCA) models linked to cropping system models (CSM) were used in the analysis. In assessing the impact of climate change on corn, wheat, and soybean crops yields, two applications of the CERES (Crop-Environment Resource Synthesis) model: CERES-Wheat (for wheat) and CERES-Maize (for corn), and CROPGRO (Crop Growth) model application: CROPGRO-Soybean of the Decision Support System for Agrotechnology Transfer (DSSAT-CSM) v4.0.2.0 model were used using observed weather data from the baseline (1981-1990) period for each study site. These models describe, based on daily data, the basic biophysical processes taking place at the soil-plant-atmosphere interface as a response to the variability of different processes such as: photosynthesis, specific phenological phases, evapotranspiration, and water dynamics in soil. Compared with the baseline, T was projected to increase by +1.5, +2, +2.5, +3, +3.5, +4, +4.5, and +5 oC, P was projected to change by ±5, ±10, ±15, and ±20%, and [CO2] was projected to increase by +70, +140, +210, +280, and + 350 ppm for Gainesville, USA. For Rothamsted, UK, T was projected to increase by +0.5, +1.5, +2.5, +3.5, and +4.5 oC, P was projected to change by ±10, and ±20%, and [CO2] was projected to increase by +70, +210, and + 350 ppm. Simulated yields output (grain/seeds and biomass) from the CSM models were used as inputs into the LCA models. Potential life cycle GHG emissions savings were calculated for corn-based biofuels: corn bioethanol (CBE), corn integrated biomethanol (CIBM), and corn integrated bioelectricity (CIBE); soybean-based biofuels: soybean biodiesel (SBD), soybean integrated biomethanol (SIBM), and soybean integrated bioelectricity (SIBE); wheat-based biofuels: wheat bioethanol (WBE), wheat integrated biomethanol (WIBM), and wheat integrated bioelectricity (WIBE). Results indicated that under the baseline (1981-1990) scenario, production and use of CBE, CIBM, CIBE, SBD, SIBM, SIBE, WBE, WIBM, and WIBE could save -4743.32 kg CO2-equiv. ha-1, -8573.31 kg CO2-equiv. ha-1, and -10996.7 kg CO2-equiv. ha-1, -2655.41 kg CO2-equiv. ha-1, -3441.1 kg CO2-equiv. ha-1, and -1350.04 kg CO2-equiv ha-1, -2776.1 kg CO2-equiv. ha-1, -500.87 kg CO2-equiv. ha-1 and -4648.93 kg CO2-equiv. ha-1 respectively, of the total life cycle GHG emissions of CO2, CH4, and N2O for the production and utilization of an energetically equivalent amount of fossil-based fuel counterpart, which they displaced. However, model predictions of future life cycle GHG emissions savings for both crops showed that the responses of corn, soybean, and wheat to simultaneous changes in T, P, and [CO2] were different under different climate change scenarios. In the future period life cycle GHG emissions savings of corn-based biofuels was predicted to decline in all cases ranging from -4.2% to -46.1%, -2.6% to -37.7%, and -1.6% to -33.4% for CBE, CIBM, and CIBE, respectively compared with the baseline (1981-1990) period. In contrast, model predictions showed that life cycle GHG emissions savings of wheat-based biofuels would increase under all climate change scenarios ranging from +2.5% to +33.5%, +0.1% to +37.8%, and +1.0% to +34.4% for WBE, WIBM, and WIBE, respectively. On the other hand, the life cycle GHG emissions savings of soybean-based biofuels was predicted to increase by +0.22% to +27%, +0.1% to 28%, and +0.1% to +31.6% for SBD, SIBM, and SIBE, respectively under some climate change scenarios (e.g., [CO2] = 680; P = +20%; and T = +1.5 oC scenario) and also decline by -0.7% to -60.8%, -0.1% to -44.6%, and -0.1% to -82.6% for SBD, SIBM, and SIBE, respectively under some climate change scenarios (e.g., [CO2] = 400; P = -20%; and T = +5 oC scenario). These results revealed that the potential impacts of climate change on energy crops productivity and net life cycle GHG emissions savings could be very large and diverse, and that the anticipated life cycle GHG emissions reductions of biofuels would not be the same in the future.