Sarah Sim

Spatial patterns of agricultural expansion determine impacts on biodiversity and carbon storage

Significance Deforestation is a major threat to biodiversity and many ecosystem services and is closely linked to agricultural expansion. Sustainability assessment of different agricultural products and policies requires an understanding of the impacts of land conversion resulting from shifts in demand or incentives for production. The prevailing approaches to estimating such impacts do not account for the spatial context of the transformation. This study shows how different patterns of agricultural expansion into forested landscapes can vastly reduce or exacerbate the total impact, suggesting that methods to measure sustainability should consider not only the total area but also where and how the landscape is converted. The agricultural expansion and intensification required to meet growing food and agri-based product demand present important challenges to future levels and management of biodiversity and ecosystem services. Influential actors such as corporations, governments, and multilateral organizations have made commitments to meeting future agricultural demand sustainably and preserving critical ecosystems. Current approaches to predicting the impacts of agricultural expansion involve calculation of total land conversion and assessment of the impacts on biodiversity or ecosystem services on a per-area basis, generally assuming a linear relationship between impact and land area. However, the impacts of continuing land development are often not linear and can vary considerably with spatial configuration. We demonstrate what could be gained by spatially explicit analysis of agricultural expansion at a large scale compared with the simple measure of total area converted, with a focus on the impacts on biodiversity and carbon storage. Using simple modeling approaches for two regions of Brazil, we find that for the same amount of land conversion, the declines in biodiversity and carbon storage can vary two- to fourfold depending on the spatial pattern of conversion. Impacts increase most rapidly in the earliest stages of agricultural expansion and are more pronounced in scenarios where conversion occurs in forest interiors compared with expansion into forests from their edges. This study reveals the importance of spatially explicit information in the assessment of land-use change impacts and for future land management and conservation.

Land use impact assessment of margarine

PurposeThis paper presents a case study of margarine, demonstrating the application of new characterisation factors (CF) for land use and a number of land use change impacts relating to biodiversity and ecosystem services. The objectives of this study were to generate insights as to the ease of applying these new factors and to assess their value in describing a number of environmental impacts from land use and land use change relating to the margarine product system.MethodsThis case study is a partial descriptive life cycle assessment (LCA) of margarine. The functional unit of the study is 500xa0g of packaged margarine used as a spread in the UK and Germany. The life cycle stages included were: agricultural production, oil processing, margarine manufacture and transportation to regional European distribution centres. Essential for the application of the new CF was the identification and quantification of the inventory flows for land occupation (land use) and land transformation (land use change) flows. A variety of methods have been applied to determine the inventory flows for the agricultural and industrial stages in the life cycle. These flows were then assessed using the new CF and land use-related environmental impact categories recommended in this special issue.Results and discussionLand occupation was the major determinant for all the new impact categories with the exception of the water purification potential. Many of the impact categories followed a similar pattern and therefore, the inventory result for land occupation in this case study explains a large share of most of the impacts. Where land occupation alone is not a suitable proxy for environmental impacts (i.e. for freshwater regulation potential), differentiation at the level of biomes has proven relevant. In addition, the land use types distinguished so far were found to be useful in highlighting likely hotspots in the life cycle, although further differentiation of ‘agricultural land’ is suggested to account for the differences between annual and permanent crops.ConclusionsThe new land use impact assessment methods applied help to identify hotspots in the life cycle of margarines, with different proportions and sources of vegetable oils. The specific impacts of each vegetable oil are determined mainly by the yield (and thus land occupation), but also by the type of agriculture (annual vs. permanent crops) and the sourcing location (and thus the sensitivity of biomes and occurrence of land use change). More research is needed to understand the usefulness of the various impact categories. For land use types, further refinement is required to describe different agricultural systems consistently across impact categories (e.g. annual vs. permanent cropping). In addition, the conceptual basis for the CFs applied in this case study (i.e. use of a potential reference for occupation and transformation) has limitations for some types of decisions normally supported by LCA.

A new approach to modeling the sediment retention service (InVEST 3.0): Case study of the Cape Fear catchment, North Carolina, USA

There is a growing call for ecosystem services models that are both simple and scientifically credible, in order to serve public and private sector decision-making processes. Sediment retention receives particular interest given the impact of this service on water quality. We developed a new version of the sediment retention model for the InVEST (Integrated Valuation of Environmental Services and Tradeoffs) tool to address previous limitations and facilitate model uncertainty assessment. We tested the model in the Cape Fear basin, North Carolina (NC), performing sensitivity analyses and assessing its ability to detect the spatial variability in sediment retention service for eight subcatchments. The main advantages of the revised model include the use of spatially-explicit, globally available input data, and the explicit consideration of hydrological connectivity in the landscape. The sensitivity analyses in the study catchment identified the erosivity and erodibility factors, together with the cover factor for agricultural land as the most influential parameter for sediment export. Relative predictions, representing the spatial variability in sediment exports, were correctly represented by the model. Absolute sediment exports were also highly correlated with observations, although their interpretation for socio-economic assessments is more uncertain without local knowledge of the dominant erosion processes. This work confirms that the sediment connectivity approach used in the revised InVEST model has great potential to quantify the sediment retention service. Although resources to conduct model calibration and testing are typically scarce, these practices should be encouraged to improve model interpretation and for confident application in different decision-making contexts. Without calibration, the InVEST sediment model still provides relevant information for ecosystem services assessments, especially in decision contexts that involve ranking of sediment export areas, such as spatial prioritization of conservation, development or restoration activities, taking into account non-linear sediment responses to changes in land use.

Degradation in carbon stocks near tropical forest edges.

Carbon stock estimates based on land cover type are critical for informing climate change assessment and landscape management, but field and theoretical evidence indicates that forest fragmentation reduces the amount of carbon stored at forest edges. Here, using remotely sensed pantropical biomass and land cover data sets, we estimate that biomass within the first 500u2009m of the forest edge is on average 25% lower than in forest interiors and that reductions of 10% extend to 1.5u2009km from the forest edge. These findings suggest that IPCC Tier 1 methods overestimate carbon stocks in tropical forests by nearly 10%. Proper accounting for degradation at forest edges will inform better landscape and forest management and policies, as well as the assessment of carbon stocks at landscape and national levels.

Sustainable Consumption and Production: Quality, Luxury and Supply Chain Equity

Sustainable development is presented as a response to the recognition of long-term limits on the human economy, expressed as three sets of constraints: techno-economic efficiency, environmental compatibility and social equity. Assessing and improving the sustainability of products and services necessarily requires a life-cycle approach, considering the complete supply chain, and examining the role of consumption as the driver for production. The economic and environmental dimensions can be explored by integrating value chain analysis (VCA) and life-cycle assessment (LCA) to show the distribution of economic benefits and environmental impacts along the supply chain. Environmental intensities (i.e. impact per unit of added value) are frequently high for material extraction and refining, and reduce progressively along the supply chain through manufacturing and distribution. Amongst other conclusions, this finding reveals inequity and unsustainability in many supply chains. Incorporating consideration of social equity in analysis of supply chains will require further methodological development, not only to record the social benefits of activities in the supply chain but also to analyse the relationship between the agents in the supply chain. This will require “soft system” analysis to complement the “hard system” approaches of VCA and LCA. From the consumption perspective, sustainable development requires not only reduction in the environmental intensity of products and services but also more equitable distribution of economic and social benefits along the supply chain. For consumers in affluent societies, income is the main determinant of consumption. A popular and acceptable message for such consumers could be that sustainable consumption is consistent with purchasing expensive items with low environmental impacts and equitable supply chains, rather than cheap and frugal items; i.e. quality and luxury rather than quantity.

Landscape configuration is the primary driver of impacts on water quality associated with agricultural expansion

Corporations and other multinational institutions are increasingly looking to evaluate their innovation and procurement decisions over a range of environmental criteria, including impacts on ecosystem services according to the spatial configuration of activities on the landscape. We have developed a spatially explicit approach and modeled a hypothetical corporate supply chain decision representing contrasting patterns of land-use change in four regions of the globe. This illustrates the effect of introducing spatial considerations in the analysis of ecosystem services, specifically sediment retention. We explored a wide variety of contexts (Iowa, USA; Mato Grosso, Brazil; and Jiangxi and Heilongjiang in China) and these show that per-area representation of impacts based on the physical characterization of a region can be misleading. We found two- to five-fold differences in sediment export for the same amount of habitat conversion within regions characterized by similar physical traits. These differences were mainly determined by the distance between land use changes and streams. The influence of landscape configuration is so dramatic that it can override wide variation in erosion potential driven by physical factors like soil type, slope, and climate. To minimize damage to spatially-dependent ecosystem services like water purification, sustainable sourcing strategies should not assume a direct correlation between impact and area but rather allow for possible nonlinearity in impacts, especially in regions with little remaining habitat and highly variable hydrological connectivity.

Life cycle assessment needs predictive spatial modelling for biodiversity and ecosystem services

International corporations in an increasingly globalized economy exert a major influence on the planets land use and resources through their product design and material sourcing decisions. Many companies use life cycle assessment (LCA) to evaluate their sustainability, yet commonly-used LCA methodologies lack the spatial resolution and predictive ecological information to reveal key impacts on climate, water and biodiversity. We present advances for LCA that integrate spatially explicit modelling of land change and ecosystem services in a Land-Use Change Improved (LUCI)-LCA. Comparing increased demand for bioplastics derived from two alternative feedstock-location scenarios for maize and sugarcane, we find that the LUCI-LCA approach yields results opposite to those of standard LCA for greenhouse gas emissions and water consumption, and of different magnitudes for soil erosion and biodiversity. This approach highlights the importance of including information about where and how land-use change and related impacts will occur in supply chain and innovation decisions.

The Role of Science in Shaping Sustainable Business: Unilever Case Study

Unilever is a leading example of a multinational company in the Fast-Moving Consumer Goods (FMCG) sector. Unilever has long been an advocate of sustainable business, using scientific assessment as the basis for its strategy and initiatives. Given its business, Life Cycle Assessment (LCA) is established within the company and there is a current focus on improving the methodology and scope of LCA. Recent developments include new approaches to fill data gaps for agricultural ingredients and new impact assessment methods for assessing land use change. We have also adapted LCA approaches to inform corporate strategy and to engage a broad range of stakeholders both within the company and outside. The most recent and significant example of this has been the use of product footprinting as an integral element of Unilever’s Sustainable Living Plan (USLP); currently over 2000 products are footprinted annually across 14 countries.

How to bring absolute sustainability into decision-making: An industry case study using a Planetary Boundary-based methodology

The Planetary Boundaries concept has emerged as a framework for articulating environmental limits, gaining traction as a basis for considering sustainability in business settings, government policy and international guidelines. There is emerging interest in using the Planetary Boundaries concept as part of life cycle assessment (LCA) for gauging absolute environmental sustainability. We tested the applicability of a novel Planetary Boundaries-based life cycle impact assessment methodology on a hypothetical laundry washing case study at the EU level. We express the impacts corresponding to the control variables of the individual Planetary Boundaries together with a measure of their respective uncertainties. We tested four sharing principles for assigning a share of the safe operating space (SoSOS) to laundry washing and assessed if the impacts were within the assigned SoSOS. The choice of sharing principle had the greatest influence on the outcome. We therefore highlight the need for more research on the development and choice of sharing principles. Although further work is required to operationalize Planetary Boundaries in LCA, this study shows the potential to relate impacts of human activities to environmental boundaries using LCA, offering company and policy decision-makers information needed to promote environmental sustainability.

Tracking current and forecasting future land-use impacts of agricultural value chains. 67th Discussion Forum on Life Cycle Assessment, 3rd of November 2017, Zurich, Switzerland

The 67th Discussion Forum on Life Cycle Assessment (LCA), organised by partners of the European project RELIEF (RELIability of product Environmental Footprints), focused on methods for better understanding the impacts of land use linked to agricultural value chains. The first session of the forum was dedicated to methods that help in retrospective tracking of land use within complex supply chains. Novel approaches were presented for the integration of increasingly available spatially located land use data into LCA. The second session focused on forward-looking projections of land use change and included emerging, predictive methods for the modelling of land change. The third session considered impact assessment methods related to the use of land and their application together with land change modelling approaches. Discussions throughout the day centred on opportunities and challenges arising from integrating spatially located land use information into Life Cycle Assessment. Increasing amounts of spatially located land use data are becoming available and this could potentially increase the robustness and specificity of Life Cycle Assessment. However, the use of such data can be computationally expensive and requires the development of skills (i.e. use of geographical information systems (GIS) and model coding) within the LCA community. Land change modelling and ecosystem service modelling are associated with considerable uncertainty which must be communicated appropriately to stakeholders and decision-makers when interpreting results from an LCA. The new approaches were found to challenge aspects of the traditional LCA approach—particularly the division between the life cycle inventory and impact assessment and the assumption of linearity between scale and impacts when deriving characterisation factors. The presentations from the DF-67 are available for download (www.lcaforum.ch), and video recordings can be accessed online (http://www.video.ethz.ch/events/lca/2017/autumn/67th.html).