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The discussion on global change has led to increased interest in glacier mass balance since glaciers can be used as climatic indicators. To meet the need for high-quality mass-balance data requires critical examination of traditional mass-balance methods and their possible errors. One issue regarding mass-balance measurements that has received little attention is internal accumulation. Our study shows that internal accumulation in the firn layer of Storglaciären, Sweden, significantly affects the mass balance of the glacier. This occurs because the winter cold wave penetrates below the previous year’s summer surface and into underlying firn. We estimated internal accumulation from measurements of temperature and water content in firn. The depth of the 0°C isotherm correlated with snow depth and air temperature, so that low snow depth and low air temperature separately cause a deeper 0°C isotherm. We determined irreducible gravimetric water content in firn to 2–3%, which corresponds to an irreducible water saturation of 6–8%. Our value for firn is relatively high compared with that for snow, probably due to trapped water in isolated firn pores. Refreezing of percolating meltwater in spring accounted for ~30% of annual internal accumulation. The remaining 70% was due to re-freezing of retained capillary water in firn pores during winter. Disregarding internal accumulation would lead to underestimation of annual net mass balance by 0.04–0.06 m w.e., corresponding to 3–5% of annual accumulation of the entire glacier in an average year. Hence, internal accumulation potentially becomes a source for systematic error if not accounted in mass-balance measurements.

Purpose The purpose of this paper is to encourage accounting regulators to address diversity in practice in the reporting of environmental liabilities. When Canada changed to International Financial Reporting Standards (IFRS) in 2011, Canadian regulators asked the IFRS Interpretations Committee to interpret whether the discount rate to value environmental liabilities should be a risk-free discount rate. Old Canadian GAAP, and current US GAAP, allow for a higher discount rate, resulting in commensurately lower liabilities. International regulators refused to address this issue expecting no diversity in practice in Canada. Design/methodology/approach The focus is on a sample of Canadian oil and gas and mining firms. These domestic industries play a major role internationally and have significant environmental liabilities. The method is empirical archival, tracking firm characteristics and discount rate choice on transition to IFRS. Findings There is significant diversity in practice. About one-third of the sample firms choose a higher discount rate, avoiding a major increase in environmental liabilities on transition to IFRS. The evidence suggests that these firms have relatively larger environmental liabilities and that the discount rate decision is a strategic choice. Research limitations/implications The sample is based on one country and may only be reflecting local anomalies that have no broader implications. Practical implications Diversity in practice in accounting for environmental liabilities is not acceptable. Accounting regulators should act to create consistent and comparable reporting practice. Social implications Firms and managers facing larger environmental liabilities can choose to minimize environmental liabilities under IFRS, while it is the general public and society at large that bear the ultimate risk. Originality/value The paper pushes forward the debate on whether recognized environmental liabilities should reflect the interests of equity investors, or if other investors and stakeholders should be taken into account.

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Renewable Electricity Futures Study: Executive SummaryMai, T.; Sandor, D.; Wiser, R.; Schneider, T (2012). Renewable Electricity Futures Study: Executive Summary. NREL/TP-6A20-52409-ES. Golden, CO: National Renewable Energy Laboratory. Renewable Electricity Futures Study Executive Summary Renewable Electricity Futures Study -Executive Summary iii PerspectiveThe Renewable Electricity Futures Study (RE Futures) provides an analysis of the grid integration opportunities, challenges, and implications of high levels of renewable electricity generation for the U.S. electric system. The study is not a market or policy assessment. Rather, RE Futures examines renewable energy resources and many technical issues related to the operability of the U.S. electricity grid, and provides initial answers to important questions about the integration of high penetrations of renewable electricity technologies from a national perspective. RE Futures results indicate that a future U.S. electricity system that is largely powered by renewable sources is possible and that further work is warranted to investigate this clean generation pathway. The central conclusion of the analysis is that renewable electricity generation from technologies that are commercially available today, in combination with a more flexible electric system, is more than adequate to supply 80% of total U.S. electricity generation in 2050 while meeting electricity demand on an hourly basis in every region of the United States.The renewable technologies explored in this study are components of a diverse set of clean energy solutions that also includes nuclear, efficient natural gas, clean coal, and energy efficiency. Understanding all of these technology pathways and their potential contributions to the future U.S. electric power system can inform the development of integrated portfolio scenarios. RE Futures focuses on the extent to which U.S. electricity needs can be supplied by renewable energy sources, including biomass, geothermal, hydropower, solar, and wind.The study explores grid integration issues using models with unprecedented geographic and time resolution for the contiguous United States. The analysis (1) assesses a variety of scenarios with prescribed levels of renewable electricity generation in 2050, from 30% to 90%, with a focus on 80% (with nearly 50% from variable wind and solar photovoltaic generation); (2) identifies the characteristics of a U.S. electricity system that would be needed to accommodate such levels; and (3) describes some of the associated challenges and implications of realizing such a future. In addition to the central conclusion noted above, RE Futures finds that increased electric system flexibility, needed to enable electricity supply-demand balance with high levels of renewable generation, can come from a portfolio of supply-and demand-side options, including flexible conventional generation, grid storage, new transmission, more responsive loads, and changes in power system operations. The analysis also finds that the abundance ...

Jansson, P., Rosqvist, G. and Schneider, T., 2005: Glacier fluctuations, suspended sediment flux and glacio-lacustrine sediments.ABSTRACT. In order to perform inverse modelling of climate variability based on palaeoclimate proxy records, the complexity of intermediate steps in the chain of processes from the climate forcing to the responding proxy has to be considered. In reconstructing climate-forced glacier fluctuations from proglacial lacustrine sediments it is important to understand how climate affects glacier dynamics. A glacier system is complex with many factors influencing sediment production, transport and deposition. Fluvial and mass movement processes in the proglacial environment may affect lake sedimentation substantially. We argue that it is easy to over-interpret glaciolacustrine sediment variability by ignoring these complications. The sediment records may contain individual layers resulting from single precipitation or melt events, as well as persistent changes in climate-forced glacier dynamics. We conclude that it is necessary to consider all possible influencing factors in order to derive reliable palaeoclimate data from lacustrine sediment sequences.