Modeling individual electricity-generating units worldwide across a range of climate–energy policy scenarios, we show that air pollution deaths are not an automatic and fixed co-benefit of climate mitigation. Rather, pollution controls and strategic retirements of power plants may ultimately determine the extent to which health co-benefits are realized.

Analyzing 39 years of hourly weather data across 42 countries, we show that, to a first approximation, the variability of solar and wind resources in a country largely determine how much "overbuilding," long-duration storage, long-distance transmission, and/or firm generation back-up will be necessary.

Analyzing global surface temperature anomalies at 1 km resolution, we find that daytime summer temps in urban areas are 3.21 °C warmer than surrounding rural areas on average, but that changing vegetation and albedo could substantially mitigate the effect. Explore the new dataset.

An overview of the main decarbonization options for cement production, bounding their relative importance and value. Deployment of CCS is key but we show that cement could potentially produce significant quantities of “negative emissions” if municipal solid waste is used as a fuel--for which there will be significantly less demand than clean biomass.

We estimate country-, process-, GHG- and product-specific land-use emissions 1961-2017. Total emissions have increased to 14.6 GtCO_2-eq in 2017 (~25% of anthropogenic GHG emissions). Our results may help prioritize mitigation efforts, but suggest drastic reductions in emissions will require similarly drastic changes in agricultural production and/or practices.

PhD student Gonzales and coauthors estimate the value of irrigation water in California and compare the agricultural costs of water shortages under both the existing water rights framework and an alternate system that allows for trading of water and could reduce the costs of water shortages by $390 million per year (4.6% of California's net agricultural revenue).

Between 2005 and 2016, Co-PI Burney estimates that decommissioning of coal-fired units in the U.S. saved roughly 23,000 lives and 329  million bushels of corn and also altered regional atmospheric reflectivity, raising average top of atmosphere instantaneous radiative forcing by 0.50 W m^-2.

Although U.S. annual CO₂ emissions fell by 24% between 2000 and 2018, committed emissions of the U.S. power sector decreased only 12% over the period. This is due to large changes in the age and composition of the U.S. generating fleet: old coal plants were replaced by brand new gas ones that can be expected to operrate for 30-40 years.

Project scientist Tarroja analyzes the relationship between in-state freshwater consumption and levelized cost of electricity for four electricity mix scenarios designed to achieve zero-carbon electricity in California by 2045.

We show that ambitious climate mitigation scenarios entail drastic, and perhaps un-appreciated, changes in the operating and/or retirement schedules of power infrastructure. For example, in 1.5 or 2°C scenarios, the median age of global coal plants at retirement is <10 years.

Graduate student Saeedmanesh and Co-PI Brouwer evaluate the impacts and capabilities of dynamically dispatching Solid Oxide Steam Electrolysis (SOSE) systems to support high penetration of renewable photovoltaic sources in the UCI microgrid.

Graduate student Saeedmanesh and Co-PI Brouwer assess the impacts of increasing deployment of Renewable Energy Sources (RES) on existing energy infrastructure has been investigated in a microgrid, an energy system that, with its constraints, foreshadows the challenges of the evolving electricity network.

This study investigates the dynamic behavior of a solid oxide steam electrolyzer (SOSE) system without an external heat source that uses transient photovoltaic (PV) generated power as an input to produce compressed (to 3 MPa) renewable hydrogen to be injected directly into the natural gas network.

Former postdoc Sadegh and team present an interactive analysis toolbox, Nexus of Food, Energy, and Water (NeFEW), that synthesizes global data for modeling and analysis of resources and their interdependencies at country-level and for user-specified categories and quantities:
Download NeFEW toolbox

We show that direct radiative effects of short-lived aerosols may substantially offset the "climate penalty" that prior studies have shown (i.e. that future climate change is likely to worsen air quality and thereby human health in most regions by favoring weather conditions that increase concentrations of air pollution).

Former Postdoc Qin (now Prof. Qin!) finds that future changes in the fraction of precipitation falling as snow and the timing of snowmelt jeopardize food production in basins where irrigated agriculture relies heavily on snowmelt runoff. We point out the most at-risk basins and crops worldwide, where adaptation of water management and agricultural systems may be especially critical in a changing climate.

Postdoc Hong et al. analyze 35 years of temperature, ozone levels, and crop yield data, and estimate the impacts of warming and ozone pollution on perennial fruits and nuts in California. These crops, which represent ~38% of the state's agriculture by value, suffer damages of about $1 billion per year due to ozone in recent years. With 2°C of warming, almond yields will drop by ~10%.

Postdoc Sloat et al. show that shifts in crop areas worldwide 1973-2012 have substantially avoided increases in growing season temperatures that would have otherwise have been experienced by rainfed maize, wheat, rice and soybean. This suggests that crop "migration" has thus far been an important adaptive mechansim.

Postdoc Hong et al demonstrate that future climate change may exacerbate the impacts of Chinese air pollution by increasing the frequency and duration of weather conditions that enhance pollution exposure. Under a scenario that avoids 3°C of mean warming but holds emissions constant, we estimate 12,100 and 8,900 more Chinese will die each year from PM_2.5 and ozone exposure, respectively.

Co-PI Moore and collaborators show that the welfare consequences of global warming on agriculture are highly asymmetric, with much larger losses at the low end of the yield distribution. This implies that the magnitude and heterogeneity of climate impacts and their welfare effects need for represented in detail in climate projections.

Postdoc Tong and coauthors show that, if operated as historically, existing fossil energy infrastructure will emit >650 Gt of CO₂, well over the most recent 1.5°C carbon budgets and 2/3 of the remaining 2°C budget. There is thus little or no room for new fossil infrastructure under the targets; rather existing infrastructure must be retired early.

Postdoc Qin and team find that some water uses are more or less flexible than others due to larger curtailment costs or social impacts. We construct and present a new water stress index that integrates water scarcity, flexibility, and variability, and use it to evaluate the most-stressed basins worldwide.

Student Saeedmanesh and Co-PI Brouwer present detailed dynamic model results to show that a solid oxide electrolysis system can follow dynamic PV generation on sunny and cloudy days with reasonable efficiency while maintaining the stack temperature gradient below a maximum set point.

Postdoc Levy and a coauthor argue that synthesis across economics and hydrology can help address two pressing sociohydrologic challenges: actionable prediction and the generation of transferable knowledge from place‐based studies.

Postdoc Levy and co-authors evaluate the implications of spatiotemporal error in precipitation data on assessing exposures to waterborne disease, and suggest that investigators should pay greater attention to limitations in using spatially heterogeneous environmental data sets to assign exposures in epidemiologic research.

PI Davis and collaborators show that concurrent drought and heat extremes in the future may cause substantial decreases in barley yields, leading to dramatic regional decreases in beer consumption (e.g., -32%) and increases in beer prices (e.g., +193%) in some years.

PI Davis, Co-PI Brouwer, and collaborators review technological opportunities and barriers for eliminating and/or managing difficult-to-decarbonize services, and critical areas for further research, development, demonstration and deployment.

PI Davis, Co-Pi Brouwer, and collaborators evaluate the University Of California’s approach to deep decarbonization, highlighting lessons in efficiency, alternative fuels and electrification. Bending the emissions curve globally requires efforts that blend academic insights with practical solutions.

PI Davis and collaborators analyze hourly weather data to show that meeting >80% of U.S. electricity demand with only solar and wind would require days' or weeks' worth of energy storage--even assuming a continental-scale transmission grid.

Co-PI Moore and collaborators use new damage functions based on the current scientific literature to estimate a new Social Cost of Carbon (SCC). Because the latest research suggests far more adverse agricultural impacts, the SCC more than doubles.

Co-PI Moore and a collaborator review and synthesize the limitations of these damage functions and describe how incorporating impacts, adaptation and vulnerability research advances and empirical findings could substantially improve damage modelling and the robustness of social cost of carbon values produced.

Co-PI Moore compares process-based and statistical models of agricultural yields and finds little evidence for differences in yield responses to warming. Rather, there is a consistent and substantial probability of large declines in welfare under 2-3°C of warming even including CO₂ fertilization.

Student Madadgar, Co-PI AghaKouchak, and PI Davis used a multivaritate probabilistic model, we quantify the average annual yields of major rainfed crops in Australia as a function of precipitation and soil moisture indices during the growing season. In the period 1980-2012, yields were 25–45% lower in dry seasons.

Student Mazdiyasni, Co-PI AghaKouchak, and PI Davis show that small increases mean temperatures may lead to big increases in heatwave deaths in India. For example, if summer mean temperatures increase by 0.5 °C, the chances of a heatwave that kills >100 people goes from roughly 1 in every 8 years to 1 in 3 years.

Student Matios and Co-PI Burney estimate water yield and water consumption as functions of land use in Fresno County, California, quantifying the discrepancy between local annual surface water yields and crop needs met by surface water allocations from outside the county and, to a much greater extent, private groundwater irrigation.