Evaluation of metrics and baselines for tracking greenhouse gas emissions trends: Recommendations for the California climate action registry

Trends in greenhouse gas emissions from consumption and production of animal food products – implications for long-term climate targets

Mitigating Curtailment and Carbon Emissions through Load Migration between Data Centers

The objective of the present work was to estimate and assess trends in greenhouse gas (GHG) emissions, particularly methane (CH4) and nitrous oxide (N2O), from dairy cows in Mexico from the base year of 1970 to 2010. Empirical and mechanistic models were used to estimate enteric methane emissions based on chemical composition of diets. Methane from manure was calculated using Intergovernmental Panel for Climate Change (IPCC) and US Environmental Protection Agency recommended equations. N2O emission was calculated according to IPCC recommendations. Compared with the 1970s, current management practices using modern dairy cows increased feed conversion efficiency 32% and milk yield 62%. GHG emission intensity (i.e. emissions per unit of product) was reduced 30%, 25% and 30% for CH4, N2O and total emissions, respectively. The study showed that although GHG emissions in absolute terms increased in the past 40 years, emission intensity decreased due to higher level of production. This trend is likely to continue in the future, assuming milk production follows the same increasing trend as in other countries in North America.

Greenhouse gas (GHG) emissions from New Zealand dairy farms are significant, representing nearly 35% of New Zealand’s total agricultural emissions. Although there is an urgent need for New Zealand to reduce agricultural GHG emissions in order to meet its Kyoto Protocol obligations, there are, as yet, few viable options for reducing farming related emissions while maintaining productivity. In addition to GHG emissions, dairy farms are also the source of other emissions, most importantly effluent from milking sheds and feed pads. It has been suggested that anaerobic digestion for biogas and energy production could be used to deal more effectively with dairy effluent while at the same time addressing concerns about farm energy supply. Dairy farms have a high demand for electricity, with a 300-cow farm consuming nearly 40 000 kWh per year. However, because only ~10% of the manure produced by the cows can be collected (e.g. primarily at milking times), a maximum of only ~16 000 kWh of electricity per year can be produced from the effluent alone. This means that anaerobic digestion/electricity generation schemes are currently economic only for farms with more than 1000 cows. A solution for smaller farms is to co-digest the effluent with unutilised pasture sourced on the farm, thereby increasing biogas production and making the system economically viable. A possible source of unutilised grass is the residual pasture left by the cows immediately after grazing. This residual can be substantial in the spring–early summer, when cow numbers (demand) can be less than the pasture growth rates (supply). The cutting of ungrazed grass (topping) is also a useful management tool that has been shown to increase pasture quality and milk production, especially over the late spring–summer. In this paper, we compare the energy and GHG balances of a conventional farm using a lagoon effluent system to one using anaerobic digestion supplemented by unutilised pasture collected by topping to treat effluent and generate electricity. For a hypothetical 300-cow, 100-ha farm, topping all paddocks from 1800 to 1600 kg DM/ha four times per year over the spring–summer would result in 80 tonnes of DM being collected, which when digested to biogas would yield 50 000 kWh (180 GJ) of electricity. This is in addition to the 16 000 kWh from the effluent digestion. About 90 GJ of diesel would be used to carry out the topping, emitting ~0.06 t CO2e/ha. In contrast, the anaerobic/topping system would offset/avoid 0.74 t CO2e/ha of GHG emissions: 0.6 t CO2e/ha of avoided CH4 emissions from the lagoon and 0.14 t CO2e/ha from biogas electricity offsetting grid electricity GHGs. For the average dairy farm, the net reduction in emissions of 0.68 CO2e/ha would equate to nearly 14% of the direct and indirect emissions from farming activities and if implemented on a national scale, could decrease GHG emissions nearly 1.4 million t CO2e or ~10% of New Zealand’s Kyoto Protocol obligations while at the same time better manage dairy farm effluent, enhance on-farm and national energy security and increase milk production through better quality pastures.

The contribution of rice production to the three major greenhouse gases CO2, CH4 and N2O in 1990, the base year of the Kyoto protocol is investigated for Japan. For the CO2 assessment, we use a top-down life cycle approach, CH4 is assessed using the Japanese GHG emission inventory and N2O is assessed according to the ratio of rice area divided by the total area of agricultural soils. In total, 1.6% of greenhouse gas (GHG) emissions in 1990 originated from rice production. Next, we assess regional variations in nine rice-producing regions, based on the CO2 data of 1990. General trends in rice production from 1960 to 2000 and data from the Japanese GHG emission inventory since 1990 are used to assess variations in time. The rice-related GHG emissions decreased to 1.05% of the total GHG emissions in 2001 and will be less than half the 1990 level in 2012, mainly due to the decrease in rice production. Contrary to the trend in GHG emissions of rice, overall GHG emissions increased as rice production fulfils important roles, in mitigating global warming and in adapting to changing climates. The protection of rice production is required to counter the increase of GHG emissions in transportation, waste and domestic sectors and to minimize problems related to landscape, water and natural hazard management.

Abstract. To track progress towards keeping global warming well below 2 ∘C or even 1.5 ∘C, as agreed in the Paris Agreement, comprehensive up-to-date and reliable information on anthropogenic emissions and removals of greenhouse gas (GHG) emissions is required. Here we compile a new synthetic dataset on anthropogenic GHG emissions for 1970–2018 with a fast-track extension to 2019. Our dataset is global in coverage and includes CO2 emissions, CH4 emissions, N2O emissions, as well as those from fluorinated gases (F-gases: HFCs, PFCs, SF6, NF3) and provides country and sector details. We build this dataset from the version 6 release of the Emissions Database for Global Atmospheric Research (EDGAR v6) and three bookkeeping models for CO2 emissions from land use, land-use change, and forestry (LULUCF). We assess the uncertainties of global greenhouse gases at the 90 % confidence interval (5th–95th percentile range) by combining statistical analysis and comparisons of global emissions inventories and top-down atmospheric measurements with an expert judgement informed by the relevant scientific literature. We identify important data gaps for F-gas emissions. The agreement between our bottom-up inventory estimates and top-down atmospheric-based emissions estimates is relatively close for some F-gas species (∼ 10 % or less), but estimates can differ by an order of magnitude or more for others. Our aggregated F-gas estimate is about 10 % lower than top-down estimates in recent years. However, emissions from excluded F-gas species such as chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs) are cumulatively larger than the sum of the reported species. Using global warming potential values with a 100-year time horizon from the Sixth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), global GHG emissions in 2018 amounted to 58 ± 6.1 GtCO2 eq. consisting of CO2 from fossil fuel combustion and industry (FFI) 38 ± 3.0 GtCO2, CO2-LULUCF 5.7 ± 4.0 GtCO2, CH4 10 ± 3.1 GtCO2 eq., N2O 2.6 ± 1.6 GtCO2 eq., and F-gases 1.3 ± 0.40 GtCO2 eq. Initial estimates suggest further growth of 1.3 GtCO2 eq. in GHG emissions to reach 59 ± 6.6 GtCO2 eq. by 2019. Our analysis of global trends in anthropogenic GHG emissions over the past 5 decades (1970–2018) highlights a pattern of varied but sustained emissions growth. There is high confidence that global anthropogenic GHG emissions have increased every decade, and emissions growth has been persistent across the different (groups of) gases. There is also high confidence that global anthropogenic GHG emissions levels were higher in 2009–2018 than in any previous decade and that GHG emissions levels grew throughout the most recent decade. While the average annual GHG emissions growth rate slowed between 2009 and 2018 (1.2 % yr−1) compared to 2000–2009 (2.4 % yr−1), the absolute increase in average annual GHG emissions by decade was never larger than between 2000–2009 and 2009–2018. Our analysis further reveals that there are no global sectors that show sustained reductions in GHG emissions. There are a number of countries that have reduced GHG emissions over the past decade, but these reductions are comparatively modest and outgrown by much larger emissions growth in some developing countries such as China, India, and Indonesia. There is a need to further develop independent, robust, and timely emissions estimates across all gases. As such, tracking progress in climate policy requires substantial investments in independent GHG emissions accounting and monitoring as well as in national and international statistical infrastructures. The data associated with this article (Minx et al., 2021) can be found at https://doi.org/10.5281/zenodo.5566761.

Embodied GHG emissions of buildings – The hidden challenge for effective climate change mitigation

Tremendous global pressures like resource depletion and climate change urge us to deploy alternate energy sources and to integrate carbon capture and sequestration processes. Biomass can be considered as one of the alternate renewable carbon-based fuels that can decrease environmental footprints in different applications. There is currently a lack of systematic review of greenhouse gas (GHG) emissions and water-energy nexus (WEN) in the biomass supply chains’ system (BSCs) system. Therefore, the present study aims to conduct a comprehensive review of the studies carried out into WEN and GHG emissions regarding the BSCs. The published papers investigated in this study were categorized and evaluated based on their objectives, methodologies, geographic scales, and environmental sustainability factors. The review revealed that not only literatures lack enough research into WEN and GHG, but also the capacity for effectively assessing the relationships between water, energy, and the trend of GHG emissions at a higher resolution. In addition, it was found that most of the previous studies have mainly focused on the economic influences of BSCs and mathematical methods for the optimization of BSCs. There is a need for the development of a mathematical dynamic model considering uncertainties and the multi-objective approaches to evaluate the trend of WEN and GHG in the BSCs. To achieve a sustainable development of the BSCs, WEN and GHG emissions need to be effectively managed. The findings of the present paper will assist researchers who work on renewable energy issues and potential users of the bioenergy industry to obtain a deeper understanding of the current state of knowledge in terms of WEN and GHG emission.

The vast majority of the scientific community believe that anthropogenic greenhouse gas (GHG) emissions are the predominant cause of climate change. One of the GHG emission sources is agriculture. Following the International Panel on Climate Change (IPCC) guidelines regarding GHG emission calculation, agriculture is responsible for around 10% of the overall global emissions. Agricultural GHG emissions consist of several emission source categories and several GHGs. In this article were described the results of multivariate statistical analyses performed on data gathered during the period 1990–2017 from the inventories of 43 Annex I countries (parties to the United Nations Framework Convention on Climate Change, UNFCCC, listed in Annex I of the Convention). Trends in the agricultural GHG emissions were analyzed. Generally, the global agricultural GHG emissions are increasing, while the emissions from Annex I countries are decreasing. Apart from the application of urea, emissions from all other sources, such as enteric fermentation, manure management, rice cultivation, agricultural soils, field burning of agricultural residues, and liming are decreasing. Based on multivariate analysis, the most different countries, in terms of GHG emission sources composition in agriculture and emission trends, are Australia, Japan, New Zealand and USA. The rest of the Annex I countries are mostly from Europe and their shares and trends are similar, with slight differences between countries depending, among others, on the date of joining the European Union.

Climate change poses significant challenges that necessitate the development of policies to manage aggregate input and social costs. To formulate such policies, an analysis of the factors and their current trends must be conducted. This study explores the factors influencing climate change and provides insights into their impacts through changes in arable land and greenhouse gas (GHG) emissions in India from 1990 to 2020. Utilizing time series analysis, this study examined trends in GHG emissions from agriculture and developed a simulation model to estimate overall GHG emissions through methane and nitrous oxide emissions. The results indicate that enteric fermentation and agricultural soil are major contributors to methane and nitrous oxide emissions, respectively, with enteric fermentation contributing approximately 69.33% and agricultural soil contributing approximately 97.66% to methane and nitrous oxide emissions, respectively. Additionally, a higher growth rate was observed for nitrous oxide emissions than for methane emissions, with nitrous oxide emissions showing a 161% increase from 1960 to 2010. Furthermore, a positive correlation (r=0.587) between GHG emissions and changes in the annual mean temperature underscores the direct impact of agricultural emissions on climate dynamics in India, with a regression coefficient factor of 0.176. It is estimated that the overall GHG emissions from agriculture through methane and nitrous oxide emissions will be approximately 695.87 to 818.73 MMTCDE in the year 2030, while the change in annual mean temperature is estimated to be approximately 1.65 ± 0.58o C from 1990 to 2030 in India. This study faces challenges such as uncertainties in long-term climate projections and emission estimates, variability in regional agricultural practices, and the need for more granular data. These findings highlight the urgent need for effective mitigation strategies within the agricultural sector to address the growing threat of climate change.

Zero carbon-emission technology route construction and multifactor analysis of aluminum production in China

Livestock production is under growing public and scientific scrutiny for its greenhouse gas (GHG) emissions. This article contains a preliminary assessment of the inclusion of upstream life-cycle GHG emissions in concentrated feeds design, using the most common nonlinear programming optimization algorithms to determine feed composition. First, GHG emissions are included as costs in a single criteria optimization problem. The unit price of GHG emissions was obtained using a genetic algorithm. Second, GHG emissions are included as a target function to minimize in a multi criteria optimization problem using goal attainment programming. Results obtained after both optimization methods were applied to two case studies, namely fattening pigs and rabbit feeds. Changing ingredients in concentrated feed blends has a marginal effect on GHG emissions due to mandatory nutritional constraints. If the optimization is unconstrained, the maximum possible decrease in GHG emissions is 27.5% for the pigs feed, accompanied by increasing costs and a decrease in feed nutritional quality. To maintain nutritional integrity, the maximum possible reduction in GHG emissions is 7.5%. Considering cost as an optimization variable in the problem, the maximum decreases are even lower. It is possible to decrease emissions by 71% for the rabbits feed, but the cost of the reduction is higher than the opportunity cost for farmers to reduce GHG emissions using other strategies. These results are qualitatively robust but critically depend on feed ingredients GHG emissions and cost data.

High yields and low carbon emissions are new challenges for modern crop production. Balancing the crop yield and reducing greenhouse gas (GHG) emissions has become a new field of agronomic technology innovation. Cereal–legume intercropping is a typical diversification planting system, which has been expected to achieve the dual goals of high production and low GHG emissions. However, the synergistic effect of integrating various technologies in an intercropping system on GHG emissions and whether it will achieve the high yield and low emissions goal remains to be determined. Therefore, bibliometric analysis has investigated the worldwide development trend of cereal–legume intercropping designs. The literature on the GHG emissions of the cereal–legume intercropping system was summarized. Additionally, the effects and mechanisms of different agricultural management methods regarding soil nitrous oxide and carbon dioxide emissions in the cereal–legume intercropping system were summarized. The research on GHG emissions of cereal–legume intercropping systems in non-growing seasons must be revised. In situ observations of GHG emissions from intercropping systems in different regions should be strengthened. This work is valuable in supporting and evaluating the potential of GHG reduction in a cereal–legume intercropping system in various farming areas.

Long-term trends in greenhouse gas emissions from the Canadian poultry industry

Greenhouse gas emissions from energy sector in the United Arab Emirates – An overview