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The potential effects of climate change on the operation of California's electric power system, on both the supply and demand sides, is an important impact category for research and for policy planning and management. It is also one of the most challenging to analyze, inasmuch as it involves the future interactions among the climate system, a highly complex, engineered technical system, and socioeconomic trends that are difficult to project in their own right. This paper uses new projections of regional climate change affecting California to generate simple illustrative estimates of possible impacts on state electricity consumption, demand, and expenditures.

This paper examines California's opportunities and constraints for managing the impacts of climate change. It reviews the extant literature on adaptation and provides examples from selected sectors in California to illuminate the constraints and, in some cases, the limits to the ability to adapt to climate change. Based on these insights, recommendations are made for how government, research, and civil society can help California most effectively prepare for climate change impacts.

This paper examines economic water management adaptations, effects, and other implications of a GFDL [i.e. Geophysical Fluid Dynamics Laboratory]-A2 year 2085 dry climate warming scenario for California's water supply system with estimated year 2050 water demands and land use.

A new approach for detecting foehn [Föhn] weather conditions, such as the Santa Ana occurrence (SAO), was performed using two Atmosphere-Ocean General Circulation Models, the GFDL and the PCM, forced with the relatively high (A2) and low (B1) greenhouse gas emissions detailed in the IPCC Special Report on Emission Scenarios. Southern California Santa Ana winds were analyzed using large-scale pressure gradients and humidity fields. Results indicate a good correlation between large-scale detected Santa Ana occurrences and observed offshore winds during periods of low humidity. The sensitivity of the number of climate change-projected SAOs was analyzed for three future time periods -- 2005-2035, 2035-2064, 2070-2099 -- and ranged from 26% to 138% of historical. GFDL A2 and B1 outcomes indicate that the warmest fall month, September, has an increase in SAO days in the early part of this century, followed by a decrease, while the PCM A2 and B1 outcomes suggest fewer SAOs during September. Meanwhile, the strongest historical SAO month, December, experiences SAO decreases for all cases during 2005-2034 and increases for 2070-2099. This initial analysis suggests that Santa Ana conditions may significantly increase during California's fire season, but in general are unlikely to be radically more or less frequent than at present.

Possible future climate changes in California are investigated from a varied set of climate change model simulations. These simulations, conducted by three state-of-the-art global climate models, provide trajectories from three greenhouse gas (GHG) emission scenarios. These scenarios and the resulting climate simulations are not "predictions," but rather are a limited sample from among the many plausible pathways that may affect California's climate. Future GHG concentrations are uncertain because they depend on future social, political, and technological pathways. In all of the simulations, most precipitation continues to occur in winter, with virtually all derived from North Pacific winter storms. Relatively little change in overall precipitation is projected. Climate warming has a profound influence in diminishing snow accumulations, because there is more rain and less snow, and earlier snowmelt. These snow losses increase as the warming increases, so that they are most severe under climate changes projected by the more sensitive model with the higher GHG emissions

This study considers a range of projected future global sea level rises in examining possible impacts at California coastal and estuarine stations. Two climate models and three scenarios are considered, providing a set of possible future weather and short-period climate fluctuations, and a range of potential long-term sea level rise values. The potential for impacts of future sea level rise is assessed from the occurrence of hourly sea level extremes. The occurrence of extreme events follows a sharply escalating pattern as the magnitude of future sea level rise increases. The confluence of low barometric pressures from storms and the presence large waves at the same time substantially increases the likelihood of high, damaging sea levels along the California coast. Similarly, astronomical tides and disturbances in sea level that are caused by weather and climate fluctuations are transmitted into the San Francisco Bay and Delta, and on into the lower reaches of the Sacramento River. In addition to elevating Bay and Delta sea levels directly through inverse barometer and wind effects, storms may generate heavy precipitation and high fresh water runoff and cause floods in the Sacramento/San Joaquin Delta, increasing the potential for inundation of levees and other structures. There may also be increased risk of levee failure due to the hydraulics and geometry of these structures. Rising sea levels from climate change will increase the frequency and duration of extreme high water levels, causing historical coastal and San Francisco Bay/Delta structure design criteria to be exceeded.

This technical note describes the methodology used to assess the impacts of different climate change scenarios on California water resources. A water resources systems model was necessary to analyze the performance of California's water system under predicted hydrologic scenarios associated with climate change. The project used CALSIM II, a model cooperatively developed by the California Department of Water Resources (DWR) and U.S. Bureau of Reclamation (USBR). Seven different climate change scenarios were considered; results showed great negative impacts on California hydrology and water resources associated with most of the scenarios analyzed.

This report focuses on public health impacts associated with climate change. Summer temperatures in California under scenarios of future climate change are projected to increase by 2°C to 7°C (3.6°F to 12.6°F) by the year 2100. Increases will be accompanied by longer, more frequent, and more severe extreme heat conditions. These increases are expected to affect human health directly through heat-related mortality, and indirectly through air pollution, potential effects on various infectious diseases, and wildfires. By the end-of-century, the likelihood of extreme heat is projected to be 2-4 times greater under the climate change scenarios examined. For an increasingly urbanized population, extreme heat waves create a significant risk of adverse health effects and heat-related mortality.

This report evaluates how global warming and the associated rise in atmospheric CO2 will affect several facets of agriculture in California: crop production, water us, and crop phenology. Analysis is based on a survey of peer-reviewed literature, an analysis of trends in crop-related climate variables, and simulations with a biophysical model, CANVEG.