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When it comes to exploiting natural resources, islands have limitations due to the quantity of these resources and the potential for harm to the ecosystem if exploitation is not done in a sustainable manner. This article presents a study of the water footprint of the different drinking water collection facilities and wastewater treatment facilities in the Canary Islands, in order to determine the blue, green, and grey water footprints in each case. The results show high percentages of drinking water losses, which raises the blue water footprint of the Canary Islands archipelago. The grey water footprint was studied in terms of Biochemical Oxygen Demand (BOD5). The green water footprint was not considered because it is a dimension of the water footprint mainly calculated for agricultural crops. Of the facilities studied, the wells for extraction of drinking water from the aquifer and the distribution network have the largest blue water footprint for the years under study (2019 and 2020). Only the wastewater treatment plants have a gray water footprint in this study, with values between 79,000 and 108,000 m3 per year. As a general conclusion, the most important factor in reducing the water footprint of the water cycle in the Canary Islands is optimization of the water resource, improving existing infrastructures to minimize losses, and implementing a greater circular economy that reuses water on a regular basis. [ABSTRACT FROM AUTHOR]

Climate change mitigation will require substantial investments in renewables. In addition, climate change will affect future renewable supply and hence, power sector investment requirements. We study the implications of climate impacts on renewables for power sector investments under deep decarbonization using a global integrated assessment model. We focus on Latin American and Caribbean, an under-studied region but of great interest due to its strong role in international climate mitigation and vulnerability to climate change. We find that accounting for climate impacts on renewables results in significant additional investments ($12–114 billion by 2100 across Latin American countries) for a region with weak financial infrastructure. We also demonstrate that accounting for climate impacts only on hydropower—a primary focus of previous studies—significantly underestimates cumulative investments, particularly in scenarios with high intermittent renewable deployment. Our study underscores the importance of comprehensive analyses of climate impacts on renewables for improved energy planning. Substantial investment will be required in renewables to implement climate change mitigation. Here, the authors focus on Latin America and the Caribbean and find that climate impacts on renewables would result in additional investments $12-114 billion by 2100. [ABSTRACT FROM AUTHOR]

Upland tropical forests have expanded and contracted in response to past climates, but it is not clear whether similar dynamics were exhibited by gallery (riparian) forests within savanna biomes. Because such forests generally have access to ample water, their extent may be buffered against changing climates. We tested the long-term stability of gallery forest boundaries by characterizing the border between gallery forests and savannas and tracing the presence of gallery forest through isotopic analysis of organic carbon in the soil profile. We measured leaf area index, grass vs. shrub or tree coverage, the organic carbon, phosphorus, nitrogen and calcium concentrations in soils and the carbon isotope ratios of soil organic matter in two transitions spanning gallery forests and savanna in a Cerrado ecosystem. Gallery forests without grasses typically show a greater leaf area index in contrast to savannas, which show dense grass coverage. Soils of gallery forests have significantly greater concentrations of organic carbon, phosphorus, nitrogen and calcium than those of savannas. Soil organic carbon of savannas is significantly more enriched in 13C compared with that of gallery forests. This difference in enrichment is in part caused by the presence of C4 grasses in savanna ecosystem and its absence in gallery forests. Using the 13C abundance as a signature for savanna and gallery forest ecosystems in 1 m soil cores, we show that the borders of gallery forests have expanded into the savanna and that this process initiated at least 3000–4000bp based on 14C analysis. Gallery forests, however, may be still expanding as we found more recent transitions according to 14C activity measurements. We discuss the possible mechanisms of gallery forest expansion and the means by which nutrients required for the expansion of gallery forest might accumulate. [ABSTRACT FROM AUTHOR]

This paper presents a comparative evaluation of methods for climate-based estimation of the net inflow rate into Lake Okeechobee, Fla. The estimated net inflow rate is used by the South Florida Water Management District (SFWMD) to support the management and operations of the Lake Okeechobee hydrologic system. The first method evaluated in this paper (Croley) uses rainfall outlooks provided by the National Oceanic and Atmospheric Administration’s Climate Prediction Center (CPC) to calculate a weighed average of historical inflow values for each month. The second method evaluated in this paper (SFWMD Empirical) uses a linear regression on statistics of historical data to predict the net inflow rate. These two methods were developed and have been used operationally by the SFWMD since 2000. Three new methods are presented and comparatively evaluated to gauge their ability in estimating net inflow rates. The first two of these methods are based on CPC issued forecasts in decile probability density format. The remaining method is based on a subsampling technique for “peer” wet/dry years in the historical record and is found to yield better results in a retrospective analysis. For extreme climatic events on the historical record, CPC rainfall outlooks are found not to yield a large enough shift in probabilities for forecasts to match observed net inflow rates; this is especially noticeable during El Niño Southern Oscillation events. Recommendations are made for potential improvements to climate-based net inflow rate estimation methods, particularly in regard to their ability to reproduce observed results for net inflow into Lake Okeechobee in the presence of an extreme climatic event, as well as over an extended climatological period. [ABSTRACT FROM AUTHOR]

Abstract Biofuels play a critical role in the Paris Agreement to help achieve climate change mitigation targets. However, a significant increase in production of biofuels might potentially be realized at the expense of overusing natural resources, particularly land and water. Understanding the tradeoffs between the impacts on land and water arises as a critical issue in the development of biofuels. This energy- water-land nexus might be particularly important for Brazil, which currently is the world's second largest producer and the largest exporter of biofuels. Furthermore, Brazil itself has set up its own Intended Nationally Determined Contribution agenda with a significant growth of biofuel production (18%) by 2030. Most studies on environmental impacts of biofuel production have either focused on land use or water use, but very few studies assessed both. Using an environmentally extended multiregional input-output (MRIO) approach, this study analyzes the current water-land nexus of bioenergy production in Brazil by quantifying the distribution of tradeoffs and synergies between land and water use for bioethanol production and its environmental consequences across Brazilian states. Our results show a clear tradeoff of water and land impacts and significant differences between irrigated and rainfed ethanol production. When including water and land scarcity in the analysis, the results are significantly different, uncovering very different tradeoffs and synergies between bioethanol producer and consumer states that could inform the expansion of bioenergy in Brazil. Compared to other crops, sugarcane has a higher comparative advantage relative to land than to water. Highlights • Biofuels play a critical role in the Paris Agreement to help achieve climate change mitigation targets. • This study analyzes the current water-land nexus of bioenergy production in Brazil. • Our results show a clear tradeoff of water and land impacts between irrigated and rainfed ethanol production. • Compared to other crops, sugarcane has a higher comparative advantage relative to land than to water. [ABSTRACT FROM AUTHOR]

In the next few decades increasing and shifting populations, urbanization, technological advances, pollution and climate change will all contribute to increased stress on limited water, energy, and land resources in several regions across the world. It is becoming increasingly clear that the feedback between these different sectors are critical and that planners and decision makers need to account for the inter-sectoral dependencies in order to capitalize on key opportunities as well as avoid unforeseen challenges which may be ignored when using single-sector approaches. In addition to cross-sectoral linkages, equally important is the spatial scale at which the resources are analyzed and managed, both because of the inherent characteristics of each resource as well as the administrative or legislative boundaries over which decisions are made and implemented. As sectoral planners adopt integrated planning approaches, a key challenge is collecting, harmonizing and synchronizing data across sectors and at decision-relevant spatial scales from large multinational regions to river sub-basins.This study seeks to contribute to this integrated panning challenge by introducing a new framework which offers planners a tool to analyze cross-sector dynamics at decision-relevant spatial scales. The framework is designed to utilize data from various models operating at different resolutions so as to capture both broader global dynamics across a range of earth and human systems (as usually done in global integrated assessment models), as well as finer-resolution sector-specific models which may capture details outside the scope of coarse-scale integrated assessment models. All data is harmonized to the spatial boundaries of interest to the stakeholder and then inter-sectoral and inter-regional links are captured via technological and trade input-output matrices. Impacts of policies and changes in one sector can then be tracked across other sectors and regions.In partnership with various government ministries and universities in Latin America, several case studies are designed to demonstrate the capabilities of the framework to analyze how various policies of interest and socio-economic changes influence the evolution of national and sub-national energy, water, and land systems in the context of a changing climate. The resulting sectoral synergies, conflicts and investment needs carry important implications for national resource management and infrastructure planning. [ABSTRACT FROM AUTHOR]