Energy-related GHG emissions balances: IPCC versus LCA

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

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 body of life cycle assessment (LCA) literature is vast and has grown over the last decade at a dauntingly rapid rate. Many LCAs have been published on the same or very similar technologies or products, in some cases leading to hundreds of publications. One result is the impression among decision makers that LCAs are inconclusive, owing to perceived and real variability in published estimates of life cycle impacts. Despite the extensive available literature and policy need formore conclusive assessments, only modest attempts have been made to synthesize previous research. A significant challenge to doing so are differences in characteristics of the considered technologies and inconsistencies in methodological choices (e.g., system boundaries, coproduct allocation, and impact assessment methods) among the studies that hamper easy comparisons and related decision support. An emerging trend is meta-analysis of a set of results from LCAs, which has the potential to clarify the impacts of a particular technology, process, product, or material and produce more robust and policy-relevant results. Meta-analysis in this context is defined here as an analysis of a set of published LCA results to estimate a single or multiple impacts for a single technology or a technology category, either in a statisticalmore » sense (e.g., following the practice in the biomedical sciences) or by quantitative adjustment of the underlying studies to make them more methodologically consistent. One example of the latter approach was published in Science by Farrell and colleagues (2006) clarifying the net energy and greenhouse gas (GHG) emissions of ethanol, in which adjustments included the addition of coproduct credit, the addition and subtraction of processes within the system boundary, and a reconciliation of differences in the definition of net energy metrics. Such adjustments therefore provide an even playing field on which all studies can be considered and at the same time specify the conditions of the playing field itself. Understanding the conditions under which a meta-analysis was conducted is important for proper interpretation of both the magnitude and variability in results. This special supplemental issue of the Journal of Industrial Ecology includes 12 high-quality metaanalyses and critical reviews of LCAs that advance understanding of the life cycle environmental impacts of different technologies, processes, products, and materials. Also published are three contributions on methodology and related discussions of the role of meta-analysis in LCA. The goal of this special supplemental issue is to contribute to the state of the science in LCA beyond the core practice of producing independent studies on specific products or technologies by highlighting the ability of meta-analysis of LCAs to advance understanding in areas of extensive existing literature. The inspiration for the issue came from a series of meta-analyses of life cycle GHG emissions from electricity generation technologies based on research from the LCA Harmonization Project of the National Renewable Energy Laboratory (NREL), a laboratory of the U.S. Department of Energy, which also provided financial support for this special supplemental issue. (See the editorial from this special supplemental issue [Lifset 2012], which introduces this supplemental issue and discusses the origins, funding, peer review, and other aspects.) The first article on reporting considerations for meta-analyses/critical reviews for LCA is from Heath and Mann (2012), who describe the methods used and experience gained in NREL's LCA Harmonization Project, which produced six of the studies in this special supplemental issue. Their harmonization approach adapts key features of systematic review to identify and screen published LCAs followed by a meta-analytical procedure to adjust published estimates to ones based on a consistent set of methods and assumptions to allow interstudy comparisons and conclusions to be made. In a second study on methods, Zumsteg and colleagues (2012) propose a checklist for a standardized technique to assist in conducting and reporting systematic reviews of LCAs, including meta-analysis, that is based on a framework used in evidence-based medicine. Widespread use of such a checklist would facilitate planning successful reviews, improve the ability to identify systematic reviews in literature searches, ease the ability to update content in future reviews, and allow more transparency of methods to ease peer review and more appropriately generalize findings. Finally, Zamagni and colleagues (2012) propose an approach, inspired by a meta-analysis, for categorizing main methodological topics, reconciling diverging methodological developments, and identifying future research directions in LCA. Their procedure involves the carrying out of a literature review on articles selected according to predefined criteria.« less

Operationalizing marketable blue carbon

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

Making sense of methods to audit emissions – various audit methods to estimate dairy production carbon footprint

An approach is presented to include a wider range of factors involved in the nitrogen and carbon cycles in agro-ecosystems than is typical of many Life Cycle Assessments (LCAs) of agriculture-based products. This use results from the process-oriented Denitrification-Decomposition (DNDC, modified version) model. Here we evaluate the effects of using site-specific N(2)O emissions derived from the DNDC model rather than the values derived from the commonly used Intergovernmental Panel on Climate Change (IPCC) Tier 1 empirical model on the results of whole life cycle greenhouse gas (GHG) profiles for wheat-based biopolymer products. Statistical methods were also used to analyze the quality of the DNDC and IPCC outputs and to characterize the uncertainty in the GHG results. The results confirm that the GHG profiles of the wheat-derived biopolymer products are sensitive to how the agricultural system is modeled and uncertainty analyses indicate that DNDC is preferred over the IPCC Tier 1 approach for site-specific LCAs. The former allows inclusion of a wider range of important site-specific agricultural parameters in the LCA, provides for improved quality in the LCA data, and permits better calibration of uncertainty in the LCA inventory.

Bioenergy from perennial grasses mitigates climate change via displacing fossil fuels and storing atmospheric CO2 belowground as soil carbon. Here, we conduct a critical review to examine whether increasing plant diversity in bioenergy grassland systems can further increase their climate change mitigation potential. We find that compared with highly productive monocultures, diverse mixtures tend to produce as great or greater yields. In particular, there is strong evidence that legume addition improves yield, in some cases equivalent to mineral nitrogen fertilization at 33–150 kg per ha. Plant diversity can also promote soil carbon storage in the long term, reduce soil N2O emissions by 30%–40%, and suppress weed invasion, hence reducing herbicide use. These potential benefits of plant diversity translate to 50%–65% greater life-cycle greenhouse gas savings for biofuels from more diverse grassland biomass grown on degraded soils. In addition, there is growing evidence that plant diversity can accelerate land restoration. Bioenergy from perennial grasses mitigates climate change via displacing fossil fuels and storing atmospheric CO2 belowground as soil carbon. Here, we conduct a critical review to examine whether increasing plant diversity in bioenergy grassland systems can further increase their climate change mitigation potential. We find that compared with highly productive monocultures, diverse mixtures tend to produce as great or greater yields. In particular, there is strong evidence that legume addition improves yield, in some cases equivalent to mineral nitrogen fertilization at 33–150 kg per ha. Plant diversity can also promote soil carbon storage in the long term, reduce soil N2O emissions by 30%–40%, and suppress weed invasion, hence reducing herbicide use. These potential benefits of plant diversity translate to 50%–65% greater life-cycle greenhouse gas savings for biofuels from more diverse grassland biomass grown on degraded soils. In addition, there is growing evidence that plant diversity can accelerate land restoration.

Achieving the Paris Agreement 1.5 C target requires a reversal of the growing atmospheric concentrations of methane, which is about 80 times more potent than CO 2 on a 20-year timescale. The Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report stated that methane is underregulated, but little is known about the effectiveness of existing methane policies. In this review, we systematically examine existing methane policies across the energy, waste, and agriculture sectors. We find that currently only about 13% of methane emissions are covered by methane mitigation policies. Moreover, the effectiveness of these policies is far from clear, mainly because methane emissions are largely calculated using potentially unrepresentative estimates instead of direct measurements. Coverage and stringency are two major blind spots in global methane policies. These findings suggest that significant and underexplored mitigation opportunities exist, but unlocking them requires policymakers to identify a consistent approach for accurate quantification of methane emission sources alongside greater policy stringency. ll

Methane emissions along biomethane and biogas supply chains are underestimated

Biodiesel is an alternative to tackle global warming, especially for reducing greenhouse gases (GHG) emissions when replacing fossil fuels. However, it can compete for land with food production. Brazil is a global player on soybeans farming and most of the biodiesel produced in the country comes from it. This work proposes a new approach to evaluate its impact, associating land use change (LUC) analysis with life cycle assessment (LCA) in a representative Brazilian soybeans farming zone. LUC assessment used Landsat satellite imagery analysis from the years 1993 and 2013, and intergovernmental panel on climate change (IPCC) guidelines to estimate GHG emissions. LCA was based on field data collection processed with SimaPro®. Results show that the increment on annual GHG emissions per hectare, derived from the apportioning total emissions for the period studied, was 50.16 kg CO2 eq ha−1 y−1. From this increment, 97.1 % come from LUC, being the largest share from converting pastures to soybeans farming (81.2 % of the total emissions). However, in the area, a large share of converted pastures are degraded, acting as source of emissions, not as sink as considered by IPCC. At the same time, practices like no-tillage make soybeans a carbon sink. Therefore, results could change if alternative approaches were to be adopted, being a challenge for future work. Therefore, when considering biodiesel from soybeans, a close regard to local land use dynamics is essential to evaluate impacts. Besides, promoting more efficient use of land already cleared with the goal to avoid deforestation can turn biodiesel into a sustainable renewable energy source.

PurposeLow carbon repair epitomises sustainable maintenance management for heritage buildings. However, there is little recognition of this aspect, coupled with impractical assessment of repair impact strategies. This paper aims to present a decision-making process based on life cycle assessment (LCA) approach of lime plaster repair options for heritage buildings.Design/methodology/approachCalculation procedures of LCA were carried out to enable sustainable maintenance management appraisal for heritage buildings upon embodied carbon expenditure expended from lime plaster repair during the maintenance phase.FindingsCalculation procedures could be understood as a carbon LCA of lime plaster repair and recognised in reducing CO2 emissions. This underpins low carbon of lime plaster repair in achieving sustainable maintenance management of heritage buildings.Practical implicationsIt must be emphasised that the LCA approach is not limited to heritage buildings and can be applied to any repair types, materials used and building forms. This supports environmentally focused economies and promotes sustainable maintenance management solutions.Social implicationsThe LCA approach highlights the efficiency of repair impact strategies through evaluation of low carbon repairs options.Originality/valueThe LCA approach results show that low carbon repair, contextualised within maintenance management, relays the “true” embodied carbon expenditure and stimulates sustainable development of heritage buildings.

In recent years, China has been vigorously carrying out the construction and development of a sponge city. To prove that the material and energy consumption involved in the implementation of a sponge city is much less than that of the integrated urban drainage system (IUDS) in addition to saved energy and reduced carbon in the sponge city, it was important to calculate the corresponding carbon source and sink and analyze its key influence factors. The emission factor method was used to calculate carbon emissions. In view of this, based on the Intergovernmental Panel on Climate Change (IPCC) guidelines and life cycle assessment (LCA), this research established a systematic accounting method for carbon emissions from the IUDS and the sponge city, which focused on improving the calculation method of the carbon sink stage. A case study was conducted in Beijing, China, and the carbon emission reduction effect of the construction of the sponge city was discussed. The results showed that the carbon emission reduction potential (CRP) of sponge facilities in this project for 50 years was 612.45 tons of CO2 equivalent after the renovation. Compared with IUDS, sponge city construction had a positive effect on carbon emission reduction and reduced carbon emissions by 87.08% on average. For the IUDS and the sponge city, the stormwater pipe network had the largest contribution of carbon emission, and its material, transportation, pipeline laying, and maintenance of stormwater pipe networks had important influences. Morris global analysis method was used to analyze the sensitivity of LCA results and obtained that the influence degree of sensitivity factors on carbon emissions in the life cycle was in the order of annual rainfall > carbon sequestration rate of green space > high-density polyethylene (HDPE) > transport distance > fertilization and insecticide. This study can provide a positive contribution to the construction of a sponge city and planning the low-carbon development of the city in the future in China.

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 10:155-162 (1998) - doi:10.3354/cr010155 The IPCC future projections: are they plausible? Vincent Gray* Climate Consultant, 75 Silverstream Road, Crofton Downs, Wellington 6004, New Zealand *E-mail: vincegray@xtra.co.nz ABSTRACT: IPCC (Intergovernmental Panel on Climate Change) future projections are based on a set of emission scenarios, IS92a to f, which are used to calculate future atmospheric concentrations of greenhouse gases. These, in turn, are used to calculate projections of radiative forcing, and then projections of future temperature and sea level change to the year 2100, using computer climate models. The assumptions of these 6 IPCC emission scenarios for the years 1995 and 2000 are compared with currently available information on greenhouse gas emissions, world population trends, and trends in world coal production. All of the scenarios exaggerate one or more of these quantities. Calculations of confidence limits on the net human-induced contribution of carbon dioxide to the atmosphere show a very high level of inaccuracy. When added to the even greater uncertainties connected with assumptions on the main greenhouse gas, water vapour, and also on clouds, plus the uncertainties of the computer models themselves, the current IPCC future projections of global temperature and sea level must be regarded as extremely unreliable. Fossil fuel emissions assumed by the IPCC scenarios for the year 2000 are plausible for scenarios IS92a, b, c and d, but not for e and f. The calculated rate of increase of atmospheric carbon dioxide concentration since 1990 assumed by the IPCC is exaggerated by 13% for all scenarios. The calculated rates of increase in atmospheric methane from 1990 to 2000 are exaggerated by 3 to 7 times, world population increases by up to 5.5%, and world coal production increases by 60 to 510%. The rate of increase of carbon dioxide in the atmosphere has been almost constant, at 0.4% a year, between 1971 and 1996, despite a 54% increase in emissions from the combustion of fossil fuels over that period. Currently suggested reductions from present emission levels are therefore unlikely to influence carbon dioxide concentrations, or global temperatures. Since all of the IS92 scenarios exaggerate one or more current climate and economic trends, the calculated future projections of atmospheric greenhouse gas concentrations are thus correspondingly exaggerated. A more realistic set of scenarios, which would include a mechanism for continuous updating, needs to be developed, thus scaling down the current values. Even if this is done, however, the accumulated inaccuracies inherent in the final calculations of climatic effects are so great as to render them unreliable as a guide to public policy. KEY WORDS: Climate change · Intergovernmental Panel on Climate Change · Emission scenarios Full text in pdf format PreviousExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 10, No. 2. Online publication date: August 14, 1998 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 1998 Inter-Research.

Determining the carbon footprint of indigenous and introduced grape varieties through Life Cycle Assessment using the island of Cyprus as a case study