Principles for life cycle inventories of land use on a global scale

Purpose

To assess the diverse environmental impacts of land use, a standardization of quantifying land use elementary flows is needed in life cycle assessment (LCA). The purpose of this paper is to propose how to standardize the land use classification and how to regionalize land use elementary flows.

Materials and methods

In life cycle inventories, land occupation and transformation are elementary flows providing relevant information on the type and location of land use for land use impact assessment. To find a suitable land use classification system for LCA, existing global land cover classification systems and global approaches to define biogeographical regions are reviewed.

Results and discussion

A new multi-level classification of land use is presented. It consists of four levels of detail ranging from very general global land cover classes to more refined categories and very specific categories indicating land use intensities. Regionalization is built on five levels, first distinguishing between terrestrial, freshwater, and marine biomes and further specifying climatic regions, specific biomes, ecoregions and finally indicating the exact geo-referenced information of land use. Current land use inventories and impact assessment methods do not always match and hinder a comprehensive assessment of land use impact. A standardized definition of land use types and geographic location helps to overcome this gap and provides the opportunity to test the optimal resolution of land cover types and regionalization for each impact pathway.

Conclusions and recommendation

The presented approach provides the necessary flexibility to providers of inventories and developers of impact assessment methods. To simplify inventories and impact assessment methods of land use, we need to find archetypical situations across impact pathways, land use types and regions, and aggregate inventory entries and methods accordingly.

     

Production and energetic utilization of wood from short rotation coppice—a life cycle assessment

Purpose  

Ambitious targets for the use of renewable energy have recently been set in the European Union. To reach these targets, a large share of future energy generation will be based on the use of woody biomass. Therefore, there is an increasing interest in the cultivation of fast-growing tree species on agricultural land outside forests. Intensive crop production is always considered to harm the environment. The study explores the environmental burdens of the cultivation of fast-growing tree species on agricultural land and their subsequent energetic conversion in comparison to the fossil reference energy system.     

Life cycle inventory modelling of land use induced by crop consumption

Background, aims and scope  

Most life cycle inventory data for crops do not include the ultimate (marginal) land use induced by crop consumption. The aims of this study were to present, document and discuss a method which can solve this problem and, furthermore, to present concrete examples for wheat consumption in Brazil, China, Denmark and the USA. A global scope is applied and the simulated adaptation to increased wheat demand corresponds to a long-term temporal scope under present market conditions with present technology.     

Updated and harmonised greenhouse gas emissions for crop inventories

Purpose

The emission of greenhouse gases (GHG) is a key criterion in the environmental assessment of biofuels. Life cycle inventories taking into account the latest methodological developments are an essential prerequisite for this assessment. In the last years, substantial progresses in the modelling of nitrogen emissions relevant for the climate as well as in modelling the emissions from land use change (LUC) have been achieved. Therefore, the biomass production inventories in the ecoinvent database were revised to take into account these developments.

Methods

The IPCC method tier 1 has been used for the assessment of N₂O emissions. Induced emissions from NH₃ and NO₃ were included as well. Due to the importance of the latter emissions for N₂O formation, these emissions have also been updated and harmonised. The Agrammon model was used for the NH₃ emissions. The SALCA-NO₃ model has been applied in the European inventories to estimate nitrate leaching, whilst in non-European inventories the SQCB-NO₃ model has been used. The quantification of the land use change areas has been based on annualized, retrospective data of the last 20 years. All carbon pools (from aboveground biomass to soil organic carbon) were considered and differentiated on a regional level for all of the natural vegetation categories affected. Whenever possible, default values and methods from the IPCC 2006 were applied.

Results and discussion

The changes for ammonia emissions were generally very small (?5 % on average). The nitrate emissions increased on average by +13 %, but this slight trend is the result of important downward and upward changes, whilst the average N₂O emissions decreased by ?26 %. For the existing inventories of soybean, palm oil and sugarcane production, significant increases of GHG emissions resulted from LUC modelling. This was mainly due to the consistent inclusion of all carbon stocks according to the IPCC guidelines. The calculation method can also result in important C sequestration effects in certain cases like African Jatropha production.

Conclusions

The changes in greenhouse gas emissions due to the updated methodology were significant. This shows that life cycle assessment studies for biofuels using older methodological bases need to be revised and could lead to different conclusions. The implemented and cultivated superstructure for LUC modelling is modular and flexible and can be easily extended to other important crop activities. The new parameterisation functionality applied for the activities provides powerful means for the simple generation of site-specific activities.

     

Application of three independent consequential LCA approaches to the agricultural sector in Luxembourg

Purpose

Consequential Life Cycle Assessment (C-LCA) is a “system modelling approach in which activities in a product system are linked so that activities are included in the product system to the extent that they are expected to change as a consequence of a change in demand”. Hence, C-LCA focuses on micro-economic actions linked to macro-economic consequences, by identifying the (marginal) suppliers and technologies prone to be affected by variable scale changes in the demand of a product. Detecting the direct and indirect environmental effects due to changes in the production system is not an easy task. Hence, researchers have combined the consequential perspective with different econometric models. Therefore, the aim of this study is to assess an increase in biocrops cultivation in Luxembourg using three different consequential modelling approaches to understand the benefits, drawbacks and assumptions linked to each approach as applied to the case study selected.

Methods

Firstly, a partial equilibrium (PE) model is used to detect changes in land cultivation based on the farmers’ revenue maximisation. Secondly, another PE model is proposed, which considers a different perspective aiming at minimising a total adaptation cost (so-called opportunity cost) to satisfy a given new demand of domestically produced biofuel. Finally, the consequential system delimitation for agricultural LCA approach, as proposed by Schmidt (Int J Life Cycle Assess 13:350–364, 2008), is applied.

Results and discussion

The two PE models present complex shifts in crop rotation land use changes (LUCs), linked to the optimisation that is performed, while the remaining approach has limited consequential impact on changes in crop patterns since the expert opinion decision tree constitutes a simplification of the ongoing LUCs. However, environmental consequences in the latter were considerably higher due to intercontinental trade assumptions recommended by the experts that were not accounted for in the economic models. Environmental variations between the different scenarios due to LUCs vary based on the different expert- or computational-based assumptions. Finally, environmental consequences as compared with the current state-of-the-art are lame due to the limited impact of the shock within the global trade market.

Conclusions

The use of several consequential modelling approaches within the same study may help widen the interpretation of the advantages or risks of applying a specific change to a production system. In fact, different models may not only be good alternatives in terms of comparability of scenarios and assumptions, but there may also be room for complementing these within a unique framework to reduce uncertainties in an integrated way.     

Land use effects on erosion and carbon storage of the Río Chimbo watershed, Ecuador

Background and aims

Soil carbon storage is an important component of global carbon cycling. Andean Andisols have high carbon content and are vulnerable to erosion because of agricultural intensification and deforestation. This study examines the effects of land use on erosion and soil carbon storage in the Río Chimbo watershed of Ecuador.

Methods

Soil carbon content, age, and erosion estimated from ¹³⁷Cs inventories was measured along an elevational transect under annual cropping, natural forest, páramo, pasture, and tree plantations.

Results

Land use, particularly annual cropping, affected ¹³⁷Cs levels in the upper soil layers, but did not have an impact on total carbon storage to a depth of 1 m. Relative erosion rates estimated from ¹³⁷Cs inventories at sites under annual cropping averaged 27 t ha^?1?y^?1 over the erosion rate of non-cultivated sites. A linear relationship was observed between soil carbon age (determined by ¹⁴C levels) and ¹³⁷Cs levels, where pasture sites had lower ¹³⁷Cs and older carbon compared to natural forest sites.

Conclusions

The effects of land use on soil loss in the Río Chimbo watershed suggest a loss and/or removal of soil carbon, particularly under annual cropping.     

Coupling GIS and LCA for biodiversity assessments of land use

Purpose  

Geospatial details about land use are necessary to assess its potential impacts on biodiversity. Geographic information systems (GIS) are adept at modeling land use in a spatially explicit manner, while life cycle assessment (LCA) does not conventionally utilize geospatial information. This study presents a proof-of-concept approach for coupling GIS and LCA for biodiversity assessments of land use and applies it to a case study of ethanol production from agricultural crops in California.     

Coupling GIS and LCA for biodiversity assessments of land use

Purpose  

Geospatial details about land use are necessary to assess its potential impacts on biodiversity. Geographic information systems (GIS) are adept at modeling land use in a spatially explicit manner, while life cycle assessment (LCA) does not conventionally utilize geospatial information. This study presents a proof-of-concept approach for coupling GIS and LCA for biodiversity assessments of land use and applies it to a case study of ethanol production from agricultural crops in California.     

A spatially explicit data-driven approach to assess the effect of agricultural land occupation on species groups

Purpose

Change of vegetation cover and increased land use intensity, particularly for agricultural use, can affect species richness. Within life cycle impact assessment, methods to assess impacts of land use on a global scale are still in need of development. In this work, we present a spatially explicit data-driven approach to characterize the effect of agricultural land occupation on different species groups.

Methods

We derived characterization factors for the direct impact of agricultural land occupation on relative species richness. Our method identifies potential differences in impacts for cultivation of different crop types, on different species groups, and in different world regions. Using empirical species richness data gathered via an extensive literature search, characterization factors were calculated for four crop groups (oil palm, low crops, Pooideae, and Panicoideae), four species groups (arthropods, birds, mammals, and vascular plants), and six biomes.

Results and discussion

Analysis of the collected data showed that vascular plant richness is more sensitive than the species richness of arthropods to agricultural land occupation. Regarding the differences between world regions, the impact of agricultural land use was lower in boreal forests/taiga than in temperate and tropical regions. The impact of oil palm plantations was found to be larger than that of Pooideae croplands, although we cannot rule out that this difference is influenced by the spatial difference between the oil palm- and Pooideae-growing regions as well. Analysis of a subset of data showed that the impact of conventional farming was larger than the impact of low-input farming.

Conclusions

The impact of land occupation on relative species richness depends on the taxonomic groups considered, the climatic region, and farm management. The influence of crop type, however, was found to be of less importance.     

Saving land to feed a growing population: consequences for consumption of crop and livestock products

Purpose

The expected increase in demand for food raises concerns about the expansion of agricultural land worldwide. To avoid expansion, we need to focus on increasing land productivity, reducing waste, and shifting human diets. Studies exploring diet shifts so far have ignored competition for land between humans and animals. Our objective was to study the relation between land use, the share of animal protein in the human diet, population size, and land availability and quality.

Methods

We used linear programming to determine minimum land required to feed a population a diet with 0–80 % of the protein derived from terrestrial domestic animals. Populations ranged from 15 million to the maximum number of people that could be supported by the system. The agricultural system in the Netherlands was used as illustration, assuming no import and export of feed and food. Daily energy and protein requirements of humans were fulfilled by a diet potentially consisting of grain (wheat), root and tuber crops (potato, sugar beet), oil crops (rapeseed), legumes (brown bean), and animal protein from ruminants (milk and meat) and monogastrics (pork).

Results and discussion

Land is used most efficiently if people would derive 12 % of dietary protein from animals (% PA), especially milk. The role of animals in such a diet is to convert co-products from crop production and the human food industry into protein-rich milk and meat. Below 12 % PA, human-inedible products were wasted (i.e., not used for food production), whereas above 12 % PA, additional crops had to be cultivated to feed livestock. Large populations (40 million or more) could be sustained only if animal protein was consumed. This results from the fact that at high population sizes, land unsuitable for crop production was necessary to meet dietary requirements of the population, and contributed to food production by providing animal protein without competing for land with crops.

Conclusions

A land use optimization model including crop and animal production enables identification of the optimal % PA in the diet. Land use per capita was lowest at 12 % PA. At this level, animals optimally consume co-products from food production. Larger populations, furthermore, can be sustained only with diets relatively high in % PA, as land unsuitable for crop production is needed to fulfil their food demand. The optimal % PA in the human diet depended on population size and the relative share of land unsuitable for crop production.

     

Generation of Phaseolus vulgaris ESTs and investigation of their regulation upon Uromyces appendiculatus infection

Background  

Phaseolus vulgaris (common bean) is the second most important legume crop in the world after soybean. Consequently, yield losses due to fungal infection, like Uromyces appendiculatus (bean rust), have strong consequences. Several resistant genes were identified that confer resistance to bean rust infection. However, the downstream genes and mechanisms involved in bean resistance to infection are poorly characterized.     

Uncertainties in the application of the species area relationship for characterisation factors of land occupation in life cycle assessment

Purpose  

Uncertainties in land use damage modeling are recognized, but hardly quantified in life cycle assessment (LCA). The objective of this study is to analyze the influence of various key assumptions and uncertainties within the development of characterisation factors (CFs) for land use in LCA. We assessed the influence on land use CFs of (1) parameter uncertainty and (2) the choice for a constant or land use-specific species accumulation factor z and including or excluding regional effects.     

Environmental rRNA inventories miss over half of protistan diversity

Background  

The main tool to discover novel microbial eukaryotes is the rRNA approach. This approach has important biases, including PCR discrimination against certain rRNA gene species, which makes molecular inventories skewed relative to the source communities. The degree of this bias has not been quantified, and it remains unclear whether species missed from clone libraries could be recovered by increasing sequencing efforts, or whether they cannot be detected in principle. Here we attempt to discriminate between these possibilities by statistically analysing four protistan inventories obtained using different general eukaryotic PCR primers.     

Land use indicators in life cycle assessment

Purpose  

Inclusion of land use-related environmental aspects into LCA methodology has been under active development in recent years. Although many indicators have been developed and proposed for different aspects of land use (climate change, biodiversity, resource depletion and soil quality), many of indicators have, as yet, not been tested and compared in LCA applications. The aim of this study is to test the different LCIA indicators in practice in a case study of beer production.     

How much does agriculture depend on pollinators? Lessons from long-term trends in crop production

Background and Aims

Productivity of many crops benefits from the presence of pollinating insects, so a decline in pollinator abundance should compromise global agricultural production. Motivated by the lack of accurate estimates of the size of this threat, we quantified the effect of total loss of pollinators on global agricultural production and crop production diversity. The change in pollinator dependency over 46 years was also evaluated, considering the developed and developing world separately.

Methods

Using the extensive FAO dataset, yearly data were compiled for 1961–2006 on production and cultivated area of 87 important crops, which we classified into five categories of pollinator dependency. Based on measures of the aggregate effect of differential pollinator dependence, the consequences of a complete loss of pollinators in terms of reductions in total agricultural production and diversity were calculated. An estimate was also made of the increase in total cultivated area that would be required to compensate for the decrease in production of every single crop in the absence of pollinators.

Key Results

The expected direct reduction in total agricultural production in the absence of animal pollination ranged from 3 to 8 %, with smaller impacts on agricultural production diversity. The percentage increase in cultivated area needed to compensate for these deficits was several times higher, particularly in the developing world, which comprises two-thirds of the land devoted to crop cultivation globally. Crops with lower yield growth tended to have undergone greater expansion in cultivated area. Agriculture has become more pollinator-dependent over time, and this trend is more pronounced in the developing than developed world.

Conclusions

We propose that pollination shortage will intensify demand for agricultural land, a trend that will be more pronounced in the developing world. This increasing pressure on supply of agricultural land could significantly contribute to global environmental change.Key words: Agricultural production, biotic pollination, crop diversity, cultivated area, developed world, developing world, FAO, randomization     

Including CO2 implications of land occupation in LCAs—method and example for livestock products

Purpose

Until recently, life cycle assessments (LCAs) have only addressed the direct greenhouse gas emissions along a process chain, but ignored the CO₂ emissions of land-use. However, for agricultural products, these emissions can be substantial. Here, we present a new methodology for including the implications of land occupation for CO₂ emissions to realistically reflect the consequences of consumers?? decisions.

Method

In principle, one can distinguish five different approaches of addressing the CO₂ consequences of land occupation: (1) assuming constant land cover, (2) land-use change related to additional production of the product under consideration, (3) historic land-use change, assuming historical relations between existing area and area expansion (4) land-use change related to less production of the product under consideration (??missed potential carbon sink?? of land occupation), and (5) an approach of integrating land conversion emissions and delayed uptake due to land occupation. Approach (4) is presented in this paper, using LCA data on land occupation, and carbon dynamics from the IMAGE model. Typically, if less production occurs, agricultural land will be abandoned, leading to a carbon sink when vegetation is regrowing. This carbon sink, which does not occur if the product would still be consumed, is thus attributed to the product as ??missed potential carbon sink??, to reflect the CO₂ implications of land occupations.

Results

We analyze the missed potential carbon sink by relating land occupation data from LCA studies to the potential carbon sink as calculated by an Integrated Global Assessment Model and its process-based, spatially explicit carbon cycle model. Thereby, we account for regional differences, heterogeneity in land-use, and different time horizons. Example calculations for several livestock products show that the CO₂ consequences of land occupation can be in the same order of magnitude as the other process related greenhouse gas emissions of the LCA, and depend largely on the production system. The highest CO₂ implications of land occupation are calculated for beef and lamb, with beef production in Brazil having a missed potential carbon sink more than twice as high as the other GHG emissions.

Conclusions

Given the significant contribution of land occupation to the total GHG balance of agricultural products, they need to be included in life cycle assessments in a realistic way. The new methodology presented here reflects the consequences of producing or not producing a certain commodity, and thereby it is suited to inform consumers fully about the consequences of their choices.     

Normalization in EDIP97 and EDIP2003: updated European inventory for 2004 and guidance towards a consistent use in practice

Purpose  

When performing a life cycle assessment (LCA), the LCA practitioner faces the need to express the characterized results in a form suitable for the final interpretation. This can be done using normalization against some common reference impact—the normalization references—which require regular updates. The study presents updated sets of normalization inventories, normalization references for the EDIP97/EDIP2003 methodology and guidance on their consistent use in practice.     

Generation and analysis of 9792 EST sequences from cold acclimated oat, <Emphasis Type="Italic">Avena sativa</Emphasis>

Background  

Oat is an important crop in North America and northern Europe. In Scandinavia, yields are limited by the fact that oat cannot be used as a winter crop. In order to develop such a crop, more knowledge about mechanisms of cold tolerance in oat is required.     

Relation between psychosocial variables and the glycemic control of patients with type 2 diabetes: A cross-sectional and prospective study

Background  

This cross-sectional and prospective study used a variety of psychological inventories to evaluate the relationship between psychosocial factors and the glycemic control of patients with type 2 diabetes.     

A spatially explicit life cycle assessment midpoint indicator for soil quality in the European Union using soil organic carbon

Purpose

Improving land use assessment in life cycle assessment (LCA) is a priority. Recently, soil organic carbon (SOC) depletion has been proposed as a transformation and occupation midpoint indicator to estimate impacts on biotic production potential (BPP). SOC depletion is recommended by the European Union in the International Reference Life Cycle Data System (ILCD) Handbook as a land use indicator. There is a consensus method to calculate SOC depletion in LCA, and ILCD proposes a set of characterization factors (CFs), but these lack geographical discrimination.

Methods

Our method of calculation for midpoint CFs follows Brandão and Milà i Canals (Int J Life Cycle Assess 18:1243–1252, 2013). We operationalize the method using SOC stocks from the LUCASOIL database of field measurements in Europe. We use potential natural vegetation (PNV) as the reference situation. CFs were calculated on a cell basis for 23 countries in Europe and grouped in three spatial scales (an administrative classification, NUTS II, and two biophysical classifications, ecoregion and climate region) according to soil type and land cover following a consensus map of cover classes. To evaluate the method’s results, CFs were applied in a case study.

Results and discussion

SOC stocks of European soils were obtained according to land use and soil type classes (excluding non-European Union countries) for the three spatial scales. A database of European transformation and occupation CFs is also presented and analyzed. The aggregation of CFs at biophysical scales (ecoregion and climate region) is similar, but NUTS II aggregation of CFs is problematic. The application of the CFs in the case study revealed significant differences compared to the outcome of using CFs collected from other land use models.

Conclusions

This paper is the first operationalization using field measurements of an updated version of the ILCD-recommended model for land use impacts in LCA. We obtained CFs for SOC depletion in Europe that can be nested within CFs suggested by ILCD since our results possess better spatial resolution but are only for European Union countries. The case study application highlighted the need for inventories to improve the spatial resolution of the life cycle processes to match the detail of LCIA models.