English

Better information on greenhouse gas (GHG) emissions and mitigation potential in the agricultural sector is necessary to manage these emissions and identify responses that are consistent with the food security and economic development priorities of countries. Critical activity data (what crops or livestock are managed in what way) are poor or lacking for many agricultural systems, especially in developing countries. In addition, the currently available methods for quantifying emissions and mitigation are often too expensive or complex or not sufficiently user friendly for widespread use.The purpose of this focus issue is to capture the state of the art in quantifying greenhouse gases from agricultural systems, with the goal of better understanding our current capabilities and near-term potential for improvement, with particular attention to quantification issues relevant to smallholders in developing countries. This work is timely in light of international discussions and negotiations around how agriculture should be included in efforts to reduce and adapt to climate change impacts, and considering that significant climate financing to developing countries in post-2012 agreements may be linked to their increased ability to identify and report GHG emissions (Murphy et al 2010, CCAFS 2011, FAO 2011).

The Ecology of Meat

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.

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Boykoff and Mansfield (2008), in a recent paper in this journal, provide a detailedanalysis of the representation of climate change in the UK tabloid newspapers.They conclude that the representation of this issue in these papers ‘diverged fromthe scientific consensus that humans contribute to climate change’. That is,portrayal of climate change in tabloid newspapers contradicts the conclusions ofthe fourth Intergovernmental Panel on Climate Change (IPCC) assessment (IPCC2007). Is it healthy to have the scientific consensus challenged so frequently? Butshould we worry about systematic misrepresentation of scientific consensus? Webelieve the answer to both of these questions is yes. To present regular updates onclimate change issues in the popular press is important because the changes inbehaviour needed to achieve substantial reductions in greenhouse gas emissionsrequire a broad understanding of the basic facts. However, if the majority ofreaders receive misleading information, it will be difficult to achieve the level ofpublic understanding necessary to make such reductions needed to avoiddangerous climate change (Schellnhuber

So far, the climate on the Earth, from beginning to end, has been changing, making in circle and not stopping. About this point, the specialists seemly have no disagreement. However, About causes of climate change, they indeed have divergence, and as for whether carbon dioxide is or not main cause of global climate warming, their divergence is much more large. Some specialists considered that natural factors are main causes led to climate change, and influence of anthropological factors on climate change is very very small. However, the other specialists considered that anthropological factors are important cause led to climate change, and also emission of greenhouse gases is main causes led to climate warming and at which, emission of carbon dioxide is the most main cause led to global climate warming. Still also some specialists consisted that carbon dioxide emitted by human activities is a chief culprit led to global warming. The Intergovernmental Panel on Climate Change (IPCC) stated that the climate on the Earth is warming. Emission of greenhouse gases led to climate warming, and carbon dioxide is main cause led to climate warming, and especially the carbon dioxide emitted by human activities is the most main cause led to global warming. Now, the climate on the earth is getting more and more warming. If the people did not control emission of carbon dioxide, the global climate warming would bring ecological cataclysm to the mankind. The climate change theory described by IPCC is called “Global warming” theory, or “Greenhouse effect” theory. The global warming theory, or greenhouse effect theory, has had very large influence on the all over the world. In China, also there are a lot of people who believe that “global warming” is true, is right and is scientific. Especially in Chinese academic circles, there are many specialists who especially believe “global warming”, and they forcefully trumpeted that the global climate is getting more and more warming. The carbon dioxide was considered as a chief culprit resulted led to global warming. Still also there are some people who placed “ global warming” theory on the god altar, and accepted some people to prostrate themselves in worship. The “Global warming” theory put forward by IPCC, at home and abroad, all has received a lot of serious criticism. According to basic theory of classical physics and basic fact of climate observation, we can prove that emission of greenhouse gases is not main cause led to climate change, and also carbon dioxide is not most main cause led to climate warming, and still also carbon dioxide emitted by human activities was not a chief culprit led to global warming. Thus, large decrease of emission of carbon dioxide cannot control the greenhouse effect, and also cannot prevent climate warming, and still also cannot stop happening of climate cataclysm.

Methane emissions along biomethane and biogas supply chains are underestimated

Debate over climate change is nothing new. Scientists have been arguing about whether greenhouse gases released by human activity might change the climate since the late nineteenth century, when Swedish chemist Svante Arrhenius first proposed that industrial emissions might cause global warming.1 Fueled by partisan bickering, this dispute now is more bellicose than ever.

The development of polymers from renewable raw materials while ensuring that the material is recyclable after the end of its life cycle is essential for Europe to achieve the goals set by the Green Deal and to approach climate neutrality in 2050. The goal of the TReResin project is to develop a new type of thermosetting resin with almost 100 % renewable raw material content, which can be recycled by changing the chemical conformation of the polymer due to the thermally reversible reactions of βamino polyesters. Within the project, Aza-Michael components, donor and acceptor, will be synthesized from used cooking oil (UCO). UCO is a waste without nutritional value generated in food processing industries, restaurants, and households. UCO is a combination of triglycerides and free fatty acids that have undergone physicochemical changes during food preparation (high temperature, moisture). Life cycle assessment (LCA) can be helpful early in the development phase, particularly for chemical processes, in identifying hotspots, comparing alternatives, assessing possible environmental implications, selecting production routes, and improving the processes themselves. The aim of the study was to evaluate the environmental impact of UCO-based AzaMichael donors and acceptors developed at the Latvian State Institute of Wood Chemistry suitable for the development of bio-based vitrimer resins. The synthesis technology currently is at TRL 2. The chosen system boundary was cradle-to-(laboratory) gate, and the functional unit was 10 g UCO-based Aza-Michael donor or acceptor. The production system for Aza-Michael components included feedstock production, required energy, and other chemicals needed for the synthesis process. The LCA model was built according to the ISO 14040/44:2006 series. LCA analysis was performed using SimaPro 9.6 software by Pré Consultants. Potential environmental impacts were assessed according to ReCiPe’s (2016) v1.1 midpoint method, and global warming potential (GWP) was assessed using the Intergovernmental Panel on Climate Change (IPCC), 2021 GWP 100a’ method. For the first time, the environmental impact of a lab-scale bio-based vitrimer component synthesis is investigated, hot spots are identified, and routes for improvement are explored. Primary data for the life cycle inventory were gathered from the experiments in the laboratory which is an advantage and best-case scenario. However, the LCA also highlighted the challenges of performing LCA on new types of chemical synthesis pathways, as background data availability and quality are limiting.

This addendum contains 2 important messages. (1) This document supersedes all previous versions of this work. Please do not use any older versions any more. (2) The atmospheric-science community now believes that it cannot estimate confidently the ''Global Warming Potentials'' (GWPs) of the indirect effects of greenhouse gases. A GWP is a number that converts a mass-unit emission of a greenhouse gas other than CO{sub 2} into the mass amount of CO{sub 2} that has an equivalent warming effect over a given period of time. This report refers to GWPs as ''CO{sub 2}-equivalency factors.'' For example, a forthcoming report by the Intergovernmental Panel on Climate Change disavows many of the GWPs estimated in an earlier IPCC report, and states that GWPs for the indirect effects of the non-CO{sub 2} greenhouse gases cannot be estimated accurately yet. However, this does not mean that in principle there are no GWPs for the non-CO{sub 2} greenhouse gases; rather, it means that some of the GWPs are uncertain, and that the earlier IPCC estimates of the GWPs may or may not turn out to be right (albeit, in at lease one case, discussed in this paper, the earlier estimates almost certainly will be wrong). In this report the author used the IPCC's 1990 estimates of the GWPs for 20-, 100-, and 500-year time horizons, and expressed the bottom-line results for each of these three time horizons. However, the recent uncertainty about the GWPs affects how you should interpret the results. Because the IPCC has disclaimed some of its GWPs, the GWPs as a group no longer are the best estimates of the warming effects over 20, 100, and 500 years. Instead, they are just a collection of possible values for the GWPs--in short, scenarios. Therefore, you should interpret the ''20-, 100-, and 500-year time horizons'' as three general GWP scenarios--say, scenarios, A, B, and C.--and not as time-period scenarios. For example, you should not think that the results shown here under the ''100-year time horizon'' actually embody the scientific community's best estimates of the relative warming potentials of the various greenhouse gases over a 100-year period. Instead, you should understand the results to be the outcome of making a particular set of assumptions about what the GWPs might be. The ''time horizons'' no longer necessarily represent time horizons, but rather general scenarios for, or assumptions about, the GWPs.

Greenhouse gas emissions from the Canadian pork industry

Evaluation of the effect of accounting method, IPCC v. LCA, on grass-based and confinement dairy systems’ greenhouse gas emissions

Greenhouse gas (GHG) emissions from post-consumer waste and wastewater are a small contributor (about 3%) to total global anthropogenic GHG emissions. Emissions for 2004-2005 totalled 1.4 Gt CO2-eq year(-1) relative to total emissions from all sectors of 49 Gt CO2-eq year(-1) [including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and F-gases normalized according to their 100-year global warming potentials (GWP)]. The CH4 from landfills and wastewater collectively accounted for about 90% of waste sector emissions, or about 18% of global anthropogenic methane emissions (which were about 14% of the global total in 2004). Wastewater N2O and CO2 from the incineration of waste containing fossil carbon (plastics; synthetic textiles) are minor sources. Due to the wide range of mature technologies that can mitigate GHG emissions from waste and provide public health, environmental protection, and sustainable development co-benefits, existing waste management practices can provide effective mitigation of GHG emissions from this sector. Current mitigation technologies include landfill gas recovery, improved landfill practices, and engineered wastewater management. In addition, significant GHG generation is avoided through controlled composting, state-of-the-art incineration, and expanded sanitation coverage. Reduced waste generation and the exploitation of energy from waste (landfill gas, incineration, anaerobic digester biogas) produce an indirect reduction of GHG emissions through the conservation of raw materials, improved energy and resource efficiency, and fossil fuel avoidance. Flexible strategies and financial incentives can expand waste management options to achieve GHG mitigation goals; local technology decisions are influenced by a variety of factors such as waste quantity and characteristics, cost and financing issues, infrastructure requirements including available land area, collection and transport considerations, and regulatory constraints. Existing studies on mitigation potentials and costs for the waste sector tend to focus on landfill CH4 as the baseline. The commercial recovery of landfill CH4 as a source of renewable energy has been practised at full scale since 1975 and currently exceeds 105 Mt CO2-eq year(-1). Although landfill CH4 emissions from developed countries have been largely stabilized, emissions from developing countries are increasing as more controlled (anaerobic) landfilling practices are implemented; these emissions could be reduced by accelerating the introduction of engineered gas recovery, increasing rates of waste minimization and recycling, and implementing alternative waste management strategies provided they are affordable, effective, and sustainable. Aided by Kyoto mechanisms such as the Clean Development Mechanism (CDM) and Joint Implementation (JI), the total global economic mitigation potential for reducing waste sector emissions in 2030 is estimated to be > 1000 Mt CO2-eq (or 70% of estimated emissions) at costs below 100 US$ t(-1) CO2-eq year(-1). An estimated 20-30% of projected emissions for 2030 can be reduced at negative cost and 30-50% at costs < 20 US$ t(-) CO2-eq year(-1). As landfills produce CH4 for several decades, incineration and composting are complementary mitigation measures to landfill gas recovery in the short- to medium-term--at the present time, there are > 130 Mt waste year(-1) incinerated at more than 600 plants. Current uncertainties with respect to emissions and mitigation potentials could be reduced by more consistent national definitions, coordinated international data collection, standardized data analysis, field validation of models, and consistent application of life-cycle assessment tools inclusive of fossil fuel offsets.

Carbon intensive but decarbonising quickly? Retrospective and prospective Life Cycle Assessments of South African pome fruit

Life cycle assessment (LCA) is a method for assessing the environmental impact of a product, activity, or system across all the stages of its life cycle. LCA can identify the activities with a major impact on the environment throughout the life cycle of a product. To analyze the environmental implications of footwear, the LCA was applied to a pair of shoes designed for professional use. In this paper, the impact of a single pair of shoes was studied. Every year, footwear production worldwide is over 22 billion pairs, which has a significant impact on the environment. In this case study, the “cradle-to-grave” approach was used, which refers to all the activities involved in the life cycle of a footwear product, starting from raw material extraction, manufacturing, use, maintenance, and, in the end, disposal. The LCA was conducted using the SimaPro software. The environmental impact assessment of the analyzed shoe needed the acquisition of two crucial datasets. Background inventory data were sourced from the Ecoinvent database (version 3.3). The impact was quantified using the Global Warming Potential (GWP) metric, which calculates the contribution of emissions to global warming over a 100-year time limit according to the established values provided by the Intergovernmental Panel on Climate Change (IPCC). The impact of greenhouse gas (GHG) emissions was measured in relative carbon dioxide equivalents (kg CO2eq) to facilitate a standardized comparison. The results show that the total carbon footprint for a pair of safety boots is 18.65 kg of CO2eq with the “component manufacture” stage as a major contributor accumulating almost 80%.