Additive effects of simulated climate changes, elevated CO2, and nitrogen deposition on grassland diversity.. Zavaleta, Erika S.; Shaw, M. Rebecca; Chiariello, Nona R.; Mooney, Harold A. & Field, Christopher B..
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC164642/ DOI: 10.1073/pnas.0932734100
Biodiversity responses to ongoing climate and atmospheric changes will affect both ecosystem processes and the delivery of ecosystem goods and services. Combined effects of co-occurring global changes on diversity, however, are poorly understood. We examined plant diversity responses in a California annual grassland to manipulations of four global environmental changes, singly and in combination: elevated CO2, warming, precipitation, and nitrogen deposition. After 3 years, elevated CO2 and nitrogen deposition each reduced plant diversity, whereas elevated precipitation increased it and warming had no significant effect. Diversity responses to both single and combined global change treatments were driven overwhelmingly by gains and losses of forb species, which make up most of the native plant diversity in California grasslands. Diversity responses across treatments also showed no consistent relationship to net primary production responses, illustrating that the diversity effects of these environmental changes could not be explained simply by changes in productivity. In two- to four-way combinations, simulated global changes did not interact in any of their effects on diversity. Our results show that climate and atmospheric changes can rapidly alter biological diversity, with combined effects that, at least in some settings, are simple, additive combinations of single-factor effects.
California is home to some of the worst air quality in the nation, notably in the San Joaquin Valley and South Coast air basins. Ninety percent of the state’s population lives in areas that are out of attainment with at least one of the federal air quality standards, which are designed to be protective of human health.
Climate change will likely make it more difficult to meet air quality standards in the future. Emission reduction measures that appear sufficient to bring a region into attainment under current conditions could be insufficient in the future, necessitating additional emission reductions. These additional reductions and the associated cost are known as the “climate penalty.” Through a process known as air quality planning, state and regional agencies are responsible for demonstrating to the US Environmental Protection Agency how California will come into compliance with federal air quality standards. Air quality planning involves the quantification of the emission reductions necessary to bring a region into compliance, the identification and design of programs to achieve those reductions, and the demonstration of compliance through modeling.
Appendix B: Base Case Forecast of California Transportation Energy Demand (Task 2). Kavalec, Chris; Stamets, Leigh; Perez, Pat; Matthews, Scott W & Therkelsen, Robert L.
California Energy Commission and California Air Resources Board :
This staff report was prepared as part of the AB 2076 (Chapter 936, Statutes of 2000) analysis. Assembly Bill 2076 (Chapter 936, Statutes of 2000) requires the California Energy Commission and the California Air Resources Board to develop and submit a strategy to the Legislature to reduce petroleum dependence in California. The statute requires the strategy to include goals for reducing the rate of growth in the demand for petroleum fuels. Options to be considered include increasing transportation energy efficiency and using non-petroleum fuels and advanced transportation technologies including alternative fueled vehicles and hybrid vehicles. The Energy Commission and the Air Resources Board have developed a program and methodologies to evaluate and analyze these possible options. The goal of this effort is to provide policy makers with a robust analysis of the possible measures that could be implemented to meet the fuel demands of consumers and industry. This analysis needs to account for the cost of these measures as well as the benefits. The overall effort is guided by consultant services provided by Acurex Environmental, an Arthur D. Little Company.
Climate change has the potential to affect many aspects of California'the survival of its unique ecosystems, its ability to produce electricity, the natural resources that support its economy, its supply of water and agricultural products, and the health of its citizens. This effort evaluated the PIER-funded studies that examined the potential impacts from climate change on these sectors, to create a knowledge base for research on climate change impacts in California and to identify paths and priorities for future research. The researchers found that those studies provided an invaluable benchmark for future research on regional climate change impacts, both in California and elsewhere. Simultaneously, they emphasize that the studies' findings be viewed not as specific predictions of future climate and impacts, but as a sensitivity analysis that considers a range of potential outcomes. The reviewers provide a series of recommendations for future studies on climate change impacts in California, involving extensions and improvements in data, methods, and modeling techniques.
ARkStorm@Tahoe. Christine M. Albano, Dale A. Cox, Michael D. Dettinger, Kevin D. Schaller, Toby L. Welborn, Maureen I. McCarthy.
This study evaluated the hydrologic sensitivity of vernal pool ecosystems in the Central Valley of California to climatic changes projected for 2100. A vernal pool water- balance model was used to evaluate rain-fed vernal pools at four locations under future conditions projected by two contrasting global climate models. The potential for change in the duration of continuous inundation, frequency of reproductively suitable inundation events, and the seasonal distribution of inundation was quantified. The potential impact of hydrologic changes varied by species and by location. Three scales of response were identified: (a) At the regional scale, pools in the middle of the Central Valley near Merced were the most responsive to climatic changes. (b) At the local scale, smaller, shallower pools had the greatest potential to change the distribution of reproductively suitable habitat available to branchiopods. (c) At the individual pool scale, changes in precipitation will dominate changes in temperature, resulting in relatively linear responses in the duration of inundation. The ecological impact of these changes will be determined by a balance between the increasing suitability of vernal pools for branchiopod predators and the hydrologic improvement of currently marginal habitats.
One of the direct consequences of climatic changes will be a rise in sea level due to the melting of land ice and the expansion of the upper layers of the ocean as they warm. This study looks at the potential costs to society of protecting against an increase in sea level, and applies this method to the San Francisco Bay area -- a region of great ecological diversity, economic importance, and vulnerability. Effects of rising sea levels around the margin of San Francisco Bay are evaluated, structural options for protecting property are identified and chosen for threatened areas, and estimates of costs of protection are determined.
Assessment of Climate Change in the Southwest United States . Gregg Garfin, Angela Jardine, Robert Merideth, Mary Black, and Sarah LeRoy.
National Climate Assessment Regional Technical Input Report Series :
Baseline and Projected Future Carbon Storage and Greenhouse-Gas Fluxes in Ecosystems of the Western United States. Zhiliang Zhu and Bradley C. Reed, Editors.
U.S. Department of the Interior, U.S. Geological Survey :
California Climate ExtremesWorkshop Report . .
Scripps Institution of Oceanography :