Time-dependent climate impact of beef production - can carbon sequestration in soil offset enteric methane emissions?

The time-dependent climate impact of beef production, including changes in soil organic carbon, was examined in this study. A hypothetical suckler cow system located in south-east Sweden was analysed using a time dependent life cycle assessment method in which yearly fluxes of greenhouse gases were considered and the climate impact in terms of temperature response over time was calculated. The climate impact expressed as carbon dioxide equivalents, i.e. global warming potential in a 100-year time perspective, was also calculated. The Introductory Carbon Balance Model was used for modelling yearly soil organic carbon changes from land use. The results showed an average carbon sequestration rate of 0.2 Mg C ha(-1) and yr(-1), so carbon sequestration could potentially counteract 15-22% of emissions arising from beef production (enteric fermentation, feed production and manure management), depending on system boundaries and production intensity. The temperature response, which showed a high initial increase due to methane emissions from enteric fermentation, started to level off after around 50 years due to the short atmospheric lifetime of methane. However, sustained production and associated methane emissions would maintain the temperature response and contribute to climate damage. A forage-grain beef system resulted in a lower climate impact than a forage-only beef system (due to higher slaughter age), even though more carbon was sequestered in the forage-only system

Climate impact of willow grown for bioenergy in Sweden

Short-rotation coppice willow (SRCW) is a fast-growing and potentially high-yielding energy crop. Transition to bioenergy has been identified in Sweden as one strategy to mitigate climate change and decrease the current dependency on fossil fuel. In this study, life cycle assessment was used to evaluate and compare the climate impacts of SRCW systems, for the purpose of evaluating key factors influencing the climate change mitigation potential of SRCW grown on agricultural land in Sweden. Seven different scenarios were defined and analysed to identify the factors with the most influence on the climate. A carbon balance model was used to model carbon fluxes between soil, biomass and atmosphere under Swedish growing conditions. The results indicated that SRCW can act as a temporary carbon sink and therefore has a mitigating effect on climate change. The most important factor in obtaining a high climate change-mitigating effect was shown to be high yield. Low yield gave the worst mitigating effect of the seven scenarios, but it was still better than the effect of the reference systems, district heating produced from coal or natural gas

Climate effects of a forestry company : including biogenic carbon fluxes and substitution effects

Forestry will play an important role in a future bioeconomy, by providing wood fibres for biomaterial and bioenergy. However, there are contradictory opinions on the climate change mitigation potential of forestry. Stora Enso, an international forestry company, has the ambition to improve its climate impact assessment at corporate level. In this work, a system perspective was applied, where greenhouse gas emissions from value chains, biogenic carbon fluxes from forest land owned or leased by Stora Enso and temporarily stored in harvested wood products, and the substitution effect, i.e. avoided emissions from substituted products and energy were considered. Furthermore, new substitution factors for pulp and paper products were developed. The estimated climate effect at corporate level was a net removal of -11.5 million Mg CO2-eq yr-1 (i.e. a climate benefit) when considering value chain emissions, biogenic carbon fluxes from forest land and harvested wood products, and avoided emissions from substitution. Uptake of biogenic carbon counteracted around 40% of the value chain emissions, while the largest climate benefit (removal of 17.9 million Mg CO2-eq) was due to substitution of more greenhouse gas-intensive products. The new substitution factors developed for pulp and paper products were applied in the climate impact calculation at company level. Important assumptions and possible improvements for future studies were identified, e.g. how to assess the impact of cascading wood use in substitution calculations

Albedo impacts of current agricultural land use: Crop-specific albedo from MODIS data and inclusion in LCA of crop production

Agricultural land use and management practices affect the global climate due to greenhouse gas (GHG) fluxes and changes in land surface properties. Increased albedo has the potential to counteract the radiative forcing and warming effect of emitted GHGs. Thus considering albedo could be important to evaluate and improve agricultural systems in light of climate change, but the albedo of individual practices is usually not known. This study quantified the albedo of individual crops under regional conditions, and evaluated the importance of albedo change for the climate impact of current crop production using life cycle assessment (LCA). Seven major crops in southern Sweden were assessed relative to a land reference without cultivation, represented by semi-natural grassland. Crop-specific albedo data were obtained from a MODIS product (MCD43A1 v6), by combining its spatial response pattern with geodata on agricultural land use 2011–2020. Fluxes of GHGs were estimated using regional data and models, including production of inputs, field operations, and soil nitrogen and carbon balances. Ten-year mean albedo was 6–11% higher under the different crops than under the reference. Crop-specific albedo varied between years due to weather fluctuations, but differences between crops were largely consistent. Increased albedo countered the GHG impact from production of inputs and field operations by 17–47% measured in GWP100, and the total climate impact was warming. Using a time-dependent metric, all crops had a net cooling impact on global mean surface temperature on shorter timescales due to albedo (3–12 years under different crops), but a net warming impact on longer timescales due to GHG emissions. The methods and data presented in this study could support increasingly comprehensive assessments of agricultural systems. Further research is needed to integrate climatic effects of land use on different spatial and temporal scales, and direct and indirect consequences from a systems perspective

Does environmental leadership pay off for Swed-ish industry? - Analyzing the effects of environ-mental investments on efficiency

Swedish environmental policy often emphasizes the importance of “taking the lead”. For example, Sweden has chosen a more ambitious climate policy target than required by the European Union (EU), namely a reduction of Swedish emissions of greenhouse gases by 40 percent by 2020 compared to the 1990 level. Government Bill 2008/09:162 emphasizes Sweden’s role as a good example in making an effort to re-duce climate change by showing that an offensive climate policy can indeed be com-bined with high economic growth. This view of environmental policy is, however, the subject of constant debate. A common argument is that environmental requirements induce private costs by forc-ing firms to make investments that crowd out other more productive investments, which hampers productivity growth and therefore competitiveness. Professor Mi-chael E. Porter of Harvard questioned this argument, and his view has become known as the Porter hypothesis (Porter, 1991). This hypothesis implies that levying stringent environmental regulations on firms enhances their productivity compared to competi-tors not subject to, or subject to lax, environmental regulations. A central message is that the connection between environmental regulation and competitiveness should be scrutinized within a dynamic framework (Porter and van der Linde, 1995). The main objective of this paper is to test the Porter hypothesis by assessing static and dynamic effects of environmental policy on productivity within the Swedish manufac-turing industry, specifically on the component total efficiency. The paper adds mainly to previous literature by using unique data on environmental protection investments, divided into investments in pollution control and pollution prevention, as a proxy for envi-ronmental regulation. The distinction between these types of investments is crucial to the understanding of the outcomes anticipated by the Porter hypothesis. The international literature studying the Porter hypothesis is extensive. A comprehen-sive review reveals that neither theoretical nor empirical literature gives general sup-port for the hypothesis (Brännlund and Lundgren, 2009). We argue that, to some ex-tent, the Porter hypothesis has not yet been given a fair chance in the empirical litera-ture, as dynamic effects are often neglected in empirical tests. Two exceptions are Managi et al. (2005) and Lanoie et al. (2008), who first estimate Total Factor Produc-tivity (TFP) scores that then are used as dependent variables in regression analyses where explanatory lagged environmental stringency measures model dynamic effects. A disadvantage with these studies is, however, that environmental stringency is ap-proximated by the cost of complying with environmental command- and-control regulations, such regulations are not emphasized by the Porter hypothesis. The empirical test of the Porter hypothesis is performed as a two-step procedure, where total efficiency scores are first estimated by adopting a stochastic production frontier function approach. In the second step, the efficiency scores are used as the dependent variable in random effects regression analyses, where the independent vari-ables are, e.g., investment in pollution control and pollution prevention. In order to assess whether these investments have dynamic effects on total efficiency these vari-ables are also lagged. If positive effects are established we cannot reject the claim that environmental leadership will benefit the Swedish industry. The estimations are based on firm level data from five Swedish industries for the period 1999-2004, and carried out for the pooled data as well as for the industries separately.

Nordic forest management towards climate change mitigation: time dynamic temperature change impacts of wood product systems including substitution effects

Climate change mitigation trade-offs between increasing harvests to exploit substitution effects versus accumulating forest carbon sequestration complicate recommendations for climate beneficial forest management. Here, a time dynamic assessment ascertains climate change mitigation potential from different rotation forest management alternatives across three Swedish regions integrating the forest decision support system Heureka RegWise with a wood product model using life cycle assessment data. The objective is to increase understanding on the climate effects of varying the forest management. Across all regions, prolonging rotations by 20% leads on average to the largest additional net climate benefit until 2050 in both, saved emissions and temperature cooling, while decreasing harvests by 20% leads to the cumulatively largest net climate benefits past 2050. In contrast, increasing harvests or decreasing the rotation period accordingly provokes temporally alternating net emissions, or slight net emission, respectively, regardless of a changing market displacement factor. However, future forest calamities might compromise potential additional temperature cooling from forests, while substitution effects, despite probable prospective decreases, require additional thorough and time explicit assessments, to provide more robust policy consultation

Nordic forest management towards climate change mitigation: time dynamic temperature change impacts of wood product systems including substitution effects

Climate change mitigation trade-offs between increasing harvests to exploit substitution effects versus accumulating forest carbon sequestration complicate recommendations for climate beneficial forest management. Here, a time dynamic assessment ascertains climate change mitigation potential from different rotation forest management alternatives across three Swedish regions integrating the forest decision support system Heureka RegWise with a wood product model using life cycle assessment data. The objective is to increase understanding on the climate effects of varying the forest management. Across all regions, prolonging rotations by 20% leads on average to the largest additional net climate benefit until 2050 in both, saved emissions and temperature cooling, while decreasing harvests by 20% leads to the cumulatively largest net climate benefits past 2050. In contrast, increasing harvests or decreasing the rotation period accordingly provokes temporally alternating net emissions, or slight net emission, respectively, regardless of a changing market displacement factor. However, future forest calamities might compromise potential additional temperature cooling from forests, while substitution effects, despite probable prospective decreases, require additional thorough and time explicit assessments, to provide more robust policy consultation

Climate effects of a forestry company – including biogenic carbon fluxes and substitution effects (2021 update)

Forestry play an important role in the bioeconomy, and will continues to do so in the future, by providing wood fibres for biomaterial and bioenergy that substitute for fossil-based alternatives, while at the same time storing carbon in forests and harvested wood products. However, there are contradictory opinions on the climate change mitigation potential of forestry. Stora Enso, an international forestry company, has the ambition to improve its climate impact assessment at corporate level. In this work, a system perspective was applied, where greenhouse gas emissions from value chains, biogenic carbon fluxes from forest land owned or leased by Stora Enso and temporarily stored in harvested wood products, and the substitution effect, i.e. avoided emissions from substituted products and energy were considered. Furthermore, new substitution factors for pulp and paper products were developed. The current report is an update of the original report, published in 2020 (Hammar et. al. 2020), based on production and value chain emissions data for the year 2021, as well as Eucalyptus plantation area as of December 2020. Overall changes in greenhouse gas fluxes relative the ones published in Hammar et al. (2020) are minor. The estimated climate effect at corporate level for 2021 is a net removal of -11.0 million Mg CO2-eq yr-1 (i.e. a climate benefit) for the year 2021 (compared to -11.5 million Mg CO2-eq yr-1 for the year 2019) when considering value chain emissions, biogenic carbon fluxes from forest land and harvested wood products, and avoided emissions from substitution. Uptake of biogenic carbon counteracted around 40% of the value chain emissions (10.2 million Mg CO2-eq yr-1), while the largest climate benefit (removal of 17.2 million Mg CO2-eq) was due to substitution of more greenhouse gas-intensive products. The same substitution factors developed in Hammar et al. (2020) for pulp and paper products were applied in the climate impact calculation at company level. Possible improvements for future studies inclued, e.g., the assessment of the impact of cascading wood use in substitution calculations

Time-Dependent Climate Impact and Energy Efficiency of Internationally Traded Non-torrefied and Torrefied Wood Pellets from Logging Residues

Demand for wood pellets as a renewable alternative to fossil fuels has increased in the past decade. However, production and use of wood pellets involves several operations (biomass extraction, chipping, transport, drying, milling, pelleting, combustion) with negative impacts on e.g. the climate. In this study, the energy efficiency and climate impact of production and use of non-torrefied and torrefied wood pellets were analysed and compared. The wood pellets, produced from logging residues extracted from a boreal coniferous forest stand (Norway spruce (Picea abies (L.) H. Karst)) in northern Sweden, were assumed to be exported and finally used in a power plant. Time-dependent life cycle assessment, expressing the climate impact as global temperature change over time, was used to include annual greenhouse gas fluxes of both fossil and biogenic origin. The results showed that carbon stock changes due to extraction of logging residues contributed most of the warming effect on global temperature. Due to greater demand for raw material, a higher warming impact per gigajoule fuel was obtained for torrefied wood pellets than for nontorrefied wood pellets. However, torrefied wood pellets demonstrated a lower climate impact (per GJ electricity) when advantages such as higher electrical energy efficiency and higher co-firing rate were ncluded. A general conclusion from this study is that replacing coal with non-torrefied or torrefied wood pellets made from logging residues can mitigate climate change. The energy output of these systems was about sevenfold the primary energy input

A Dynamic Aspartate-to-Alanine Aminotransferase Ratio Provides Valid Predictions of Incident Severe Liver Disease

The aspartate-to-alanine aminotransferase ratio (AAR) is associated with liver fibrosis, but its predictive performance is suboptimal. We hypothesized that the association between AAR and liver disease depends on absolute transaminase levels and developed and validated a model to predict liver-related outcomes in the general population. A Cox regression model based on age, AAR, and alanine aminotransferase (ALT) level (dynamic AAR [dAAR]) using restricted cubic splines was developed in Finnish population-based health-examination surveys (FINRISK, 2002-2012; n = 18,067) with linked registry data for incident liver-related hospitalizations, hepatocellular carcinoma, or liver death. The model was externally validated for liver-related outcomes in a Swedish population cohort (Swedish Apolipoprotein Mortality Risk [AMORIS] subcohort; n = 126,941) and for predicting outcomes and/or prevalent fibrosis/cirrhosis in biopsied patients with nonalcoholic fatty liver disease (NAFLD), chronic hepatitis C, or alcohol-related liver disease (ALD). The dynamic AAR model predicted liver-related outcomes both overall (optimism-corrected C-statistic, 0.81) and in subgroup analyses of the FINRISK cohort and identified persons with >10% risk for liver-related outcomes within 10 years. In independent cohorts, the C-statistic for predicting liver-related outcomes up to a 10-year follow-up was 0.72 in the AMORIS cohort, 0.81 in NAFLD, and 0.75 in ALD. Area-under-the-curve (AUC) for detecting prevalent cirrhosis was 0.80-0.83 in NAFLD, 0.80 in hepatitis C, but only 0.71 in ALD. In ALD, model performance improved when using aspartate aminotransferase instead of ALT in the model (C-statistic, 0.84 for outcome; AUC, 0.82 for prevalent cirrhosis). Conclusion: A dAAR score provides prospective predictions for the risk of incident severe liver outcomes in the general population and helps detect advanced liver fibrosis/cirrhosis. The dAAR score could potentially be used for screening the unselected general population and as a trigger for further liver evaluations.Peer reviewe