This study investigates different sources of uncertainty in the assessment of the climate change impacts on total monthly precipitation in the Campbell River basin, British Columbia, Canada. Four global climate models (GCMs), three greenhouse gas emission scenarios (RCPs) and six downscaling methods (DSMs) are used in the assessment. These sources of uncertainty are analyzed separately for two future time periods (2036 to 2065 and 2066 to 2095). An uncertainty metric is calculated based on the variation in simulated precipitation due to choice of GCMs, emission scenarios and downscaling models. The results show that the selection of a downscaling method provides the largest amount of uncertainty when compared to the choice of GCM and/or emission scenario. However, the choice of GCM provides a significant amount of uncertainty if downscaling methods are not considered. This assessment work is conducted at ten different locations in the Campbell River basin.

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Approximately 20% of wastewaters globally do not receive treatment, whereas wastewater discharges are projected to increase, thereby leading to excessive water quality degradation of surface waters on a global scale. Increased treatment could help alleviate water quality issues by constructing more treatment plants; however, in many areas there exist economic constraints. Energy recovery methods including the utilization of biogas and incineration of biosolids generated during the treatment process may help to alleviate treatment costs. This study explores the potential for investments in energy recovery from wastewater to increase treatment levels and thus improve surface water quality. This was done by examining the relationships between nutrient over-enrichment, wastewater treatment, and energy recovery at a global scale using system dynamics simulation as part of the ANEMI integrated assessment model. The results show that a significant amount of energy can be recovered from wastewater, which helps to alleviate some of the costs of treatment. It was found that wastewater treatment levels could be increased by 34%, helping to offset the higher nutrient loading from a growing population with access to improved sanitation. The production of renewable natural gas from biogas was found to have the potential to prolong the depletion of natural gas resources used to produce electricity and heat. It is recommended that agricultural nutrient discharges be better managed to help reduce nutrient over-enrichment on global scale. To increase the utility of the simulation, a finer spatial scale should be used to consider regional treatment, economic, and water quality characteristics.

The ANEMI model is an integrated assessment model of global change that emphasizes the role of water resources. Securing water resources for the future is a key issue of global change and ties into global systems of population growth, climate change carbon cycle, hydrologic cycle, economy, energy production, land use and pollution generation. The focus of the presented work is on the development of global water supplies necessary to keep pace with a growing population and global economy. With the structure of the ANEMI model, a series of experiments are conducted in order to assess: (i) the current role of water supply in the global Earth system; (ii) the level of water stress that can be expected in the future; and (iii) what are the potential effects of water quality on global surface water supply and the distribution of water supply types. The results of model simulations show that surface water resources were sufficient to meet the water demand and water quality is not shown to be a significant factor for the development of surface water supplies. Due to globally aggregated scale, these impacts are averaged and likely understated.