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The United Nations's Sustainable Development Goals (SDGs) is international cooperation that aims to climate change mitigation, and encourage the use of clean energy. Investing in green technology to reduce carbon dioxide (CO 2 ) emissions is among the most important objective of the SDGs. As the USA is part of this collaboration, the present study tries to examine the progress of one State to meet the Global Goals. This paper uses the autoregressive distributed lags (ARDLs) approach and Granger causality test to evaluate the dynamic relationships uniting gross domestic product (GDP), CO 2 emissions, renewable energy consumption (REC), and research and development (R&D) for the California State over the period 1987-2017. The outcome of the econometric analysis proved that REC affects CO 2 emissions in the short run, and vice versa. In addition, a bidirectional relationship is detected between GDP and R&D and CO 2 emissions and REC Granger causes GDP. In the long run, REC, R&D, and GDP Granger cause CO 2 emissions, while REC, R&D, and CO 2 emissions Granger cause GDP. We also found a bidirectional causality linking CO 2 emissions and GDP. The long-run elasticities show that R&D and GDP impact positively CO 2 emissions whereas REC affects it. Thus, R&D increases pollution but REC reduces it. Environmental degradation is perhaps related to the excessive consumption of fossil energy in most activities. California is advised to enhance the effort to meet the SDGs. Encouraging R&D of low carbon technologies and applying several taxations for non-renewable fuel adoption may also constitute a useful strategy to protect the environment., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Food waste is a dominant organic constituent of landfills, and a large global source of greenhouse gases. Composting food waste presents a potential opportunity for emissions reduction, but data on whole pile, commercial-scale emissions and the associated biogeochemical drivers are lacking. We used a non-invasive micrometeorological mass balance approach optimized for three-dimensional commercial-scale windrow compost piles to measure methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) emissions continuously during food waste composting. Greenhouse gas flux measurements were complemented with continuous oxygen (O2) and temperature sensors and intensive sampling for biogeochemical processes. Emission factors (EF) ranged from 6.6 to 8.8 kg CH4–C/Mg wet food waste and were driven primarily by low redox and watering events. Composting resulted in low N2O emissions (0.01 kg N2O–N/Mg wet food waste). The overall EF value (CH4 + N2O) for food waste composting was 926 kgCO2e/Mg of dry food waste. Composting emissions were 38–84% lower than equivalent landfilling fluxes with a potential net minimum savings of 1.4 MMT CO2e for California by year 2025. Our results suggest that food waste composting can help mitigate emissions. Increased turning during the thermophilic phase and less watering overall could potentially further lower emissions. [ABSTRACT FROM AUTHOR]

Alfalfa is the most widely grown forage crop worldwide and is thought to be a significant carbon sink due to high productivity, extensive root systems, and nitrogen-fixation. However, these conditions may increase nitrous oxide (N2O) emissions thus lowering the climate change mitigation potential. We used a suite of long-term automated instrumentation and satellite imagery to quantify patterns and drivers of greenhouse gas fluxes in a continuous alfalfa agroecosystem in California. We show that this continuous alfalfa system was a large N2O source (624 ± 28 mg N2O m2 y−1), offsetting the ecosystem carbon (carbon dioxide (CO2) and methane (CH4)) sink by up to 14% annually. Short-term N2O emissions events (i.e., hot moments) accounted for ≤1% of measurements but up to 57% of annual emissions. Seasonal and daily trends in rainfall and irrigation were the primary drivers of hot moments of N2O emissions. Significant coherence between satellite-derived photosynthetic activity and N2O fluxes suggested plant activity was an important driver of background emissions. Combined data show annual N2O emissions can significantly lower the carbon-sink potential of continuous alfalfa agriculture. Long-term continuous greenhouse gas measurements in alfalfa cropland showed that the magnitude of the carbon sink was significantly offset by large nitrous oxide (N2O) emission events following irrigation and rainfall. [ABSTRACT FROM AUTHOR]

This paper estimates the potential emission savings that could be achieved if the jacket of a large California oil and gas platform is partially removed and converted to an artificial reef rather than fully removed. The platform selected for study is Platform Harvest which is located on the federal Outer Continental Shelf (OCS) offshore Point Conception in Santa Barbara County, California. Platform Harvest, a large steel jacketed structure located in 675 feet of water, ceased production in 2015 and plans are now being developed for removing the structure. Under the partial removal option, the upper sections of the jacket would be removed to a depth of 85 feet below the ocean surface with the remainder left in-situ to serve as an artificial reef. The full removal option involves removing the entire jacket by cutting the jacket legs and piles off 15 feet below the seabed, cutting the jacket into sections for lifting by a heavy lift vessel, and transporting the jacket components on cargo barges to shore for recycling or disposal. The results of the study show the partial removal jacket option would result in a 10-fold reduction in emissions of nitrogen oxide, sulfur dioxide, green-house gases, and other criteria pollutants as compared to the full removal option. • Considers air emissions savings from partially removing a large platform and reefing the remaining jacket material in-situ. • Fully removing the Platform Harvest jacket is estimated to produce 1147 tons of NOx and 56,187 tons of GHG emissions. • NOx emissions produced by complete removal exceeds by a factor of three the current permitted facility emission levels. • Determines that the air emissions savings due to reefing is approximately a factor of 10 compared to complete removal. • Fully removing a platform jacket will produce a large quantity of emissions of criteria pollutants and greenhouse gases. • Poses a major challenge to operators seeking to obtain permits for projects from air quality regulatory agencies [ABSTRACT FROM AUTHOR]