Applying the Human Appropriation of Net Primary Production framework to map provisioning ecosystem services and their relation to ecosystem functioning across the European Union.

Human intervention on land enhances the supply of provisioning ecosystem services, but also exerts pressures on ecosystem functioning. We utilize the Human Appropriation of Net Primary Production (HANPP) framework to assess these relations in European agriculture, for 220 NUTS2 regions. We put a particular focus on individual land system components, i.e. croplands, grasslands, and livestock husbandry and relate associated biomass flows to the potential net primary productivity NPP. For the reference year 2012, we find that 469 g dm/m2/yr (38% of NPPpot) of used biomass were harvested on total agricultural land, and that one tonne of annually harvested biomass is associated with 1.67 tonnes dry matter (dm) of HANPP, ranging from 0.8 to 8.1 tonnes dry matter (dm) across all regions. EU livestock systems are a large consumer of these provisioning ecosystem services, and invoking higher HANPP flows than current HANPP on cropland and grassland within the EU, even exceeding the potential NPP in one fifth of all NUTS2 regions. NPP remaining in ecosystems after provisioning society with biomass is essential for the functioning of ecosystems and is 563 g dm/m2/yr or 46% of NPPpot on all agricultural land. We conclude from our analysis that the HANPP framework provides useful indicators that should be integrated in future ecosystem service assessments.

Global process-based characterization factors of soil carbon depletion for life cycle impact assessment.

Regionalization of land use (LU) impact in life cycle assessment (LCA) has gained relevance in recent years. Most regionalized models are statistical, using highly aggregated spatial units and LU classes (e.g. one unique LU class for cropland). Process-based modelling is a powerful characterization tool but so far has never been applied globally for all LU classes. Here, we propose a new set of spatially detailed characterization factors (CFs) for soil organic carbon (SOC) depletion. We used SOC dynamic curves and attainable SOC stocks from a process-based model for more than 17,000 world regions and 81 LU classes. Those classes include 63 agricultural (depending on 4 types of management/production), and 16 forest sub-classes, and 1 grassland and 1 urban class. We matched the CFs to LU elementary flows used by LCA databases at country-level. Results show that CFs are highly dependent on the LU sub-class and management practices. For example, transformation into cropland in general leads to the highest SOC depletion but SOC gains are possible with specific crops.

Food systems in a zero-deforestation world: Dietary change is more important than intensification for climate targets in 2050.

Global food systems contribute to climate change, the transgression of planetary boundaries and deforestation. An improved understanding of the environmental impacts of different food system futures is crucial for forging strategies to sustainably nourish a growing world population. We here quantify the greenhouse gas (GHG) emissions of global food system scenarios within a biophysically feasible "option space" in 2050 comprising all scenarios in which biomass supply - calculated as function of agricultural area and yields - is sufficient to cover biomass demand - derived from human diets and the feed demand of livestock. We assessed the biophysical feasibility of 520 scenarios in a hypothetical no-deforestation world. For all feasible scenarios, we calculate (in) direct GHG emissions related to agriculture. We also include (possibly negative) GHG emissions from land-use change, including changes in soil organic carbon (SOC) and carbon sinks from vegetation regrowth on land spared from food production. We identify 313 of 520 scenarios as feasible. Agricultural GHG emissions (excluding land use change) of feasible scenarios range from 1.7 to 12.5 Gt CO2e yr-1. When including changes in SOC and vegetation regrowth on spare land, the range is between -10.7 and 12.5 Gt CO2e yr-1. Our results show that diets are the main determinant of GHG emissions, with highest GHG emissions found for scenarios including high meat demand, especially if focused on ruminant meat and milk, and lowest emissions for scenarios with vegan diets. Contrary to frequent claims, our results indicate that diets and the composition and quantity of livestock feed, not crop yields, are the strongest determinants of GHG emissions from food-systems when existing forests are to be protected.

Detailed global modelling of soil organic carbon in cropland, grassland and forest soils.

Assessments of the global carbon (C) cycle typically rely on simplified models which consider large areas as homogeneous in terms of the response of soils to land use or consider very broad land classes. For example, "cropland" is typically modelled as an aggregation of distinct practices and individual crops over large regions. Here, we use the process-based Rothamsted soil Carbon Model (RothC model), which has a history of being successfully applied at a global scale, to calculate attainable SOC stocks and C mineralization rates for each of c. 17,000 regions (combination of soil type and texture, climate type, initial land use and country) in the World, under near-past climate conditions. We considered 28 individual crops and, for each, multiple production practices, plus 16 forest types and 1 grassland class (total of 80 classes). We find that conversion to cropland can result in SOC increases, particularly when the soil remains covered with crop residues (an average gain of 12 t C/ha) or using irrigation (4 t C/ha), which are mutually reinforcing effects. Attainable SOC stocks vary significantly depending on the land use class, particularly for cropland. Common aggregations in global modelling of a single agricultural class would be inaccurate representations of these results. Attainable SOC stocks obtained here were compared to long-term experiment data and are well aligned with the literature. Our results provide a regional and detailed understanding of C sequestration that will also enable better greenhouse gas reporting at national level as alternatives to IPCC tier 2 defaults.

Consolidating Regionalized Global Characterization Factors for Soil Organic Carbon Depletion Due to Land Occupation and Transformation.

Land occupation and transformation change soil organic carbon (SOC) stocks, which are a priority indicator for biotic production potential (BPP) in life cycle impact assessment (LCIA). SOC is a potential umbrella indicator for land use-related impacts, but global LCIA characterization models have never been sufficiently regionalized. Regeneration times required for the calculation of transformation impacts are unknown and can only be estimated through expert judgment or using additional assumptions. In this paper, we calculate global midpoint characterization factors (CF) for SOC depletion following land use and land use change using data from the European Soil Data Center with a resolution of 30 arc second. We used three possible calculation procedures to determine regeneration times: (1) estimations based on literature; (2) equal regeneration duration for all land uses; (3) equal regeneration rates for all land uses. We then propose an innovative approach for LCIA that combines all CFs in this paper as well as prior models using a spatial consolidation approach to arrive at a single set of CFs. We show that this procedure combines the strengths of each individual model and dilutes their shortcomings, and recommend the use of these consolidated CFs rather than individual sets of factors. For endpoints, we applied a nutrient replacement method using fertilizer input to compensate for organic matter depletion and obtained monetary CFs for SOC-related damages caused by land use on BPP.

A step toward regionalized scale-consistent agricultural life cycle assessment inventories.

Life cycle inventory (LCI) regionalization (i.e., the determination of input and output flows from production processes at a subcountry scale) is a priority in life cycle assessment (LCA) studies, particularly in the agri-food sector. Many regionalized LCAs fail to ensure that microlevel inventories are consistent with country-level aggregated data-or "scale consistent." They also fail to construct LCIs using international reference guidelines and trustworthy standardized data sources. This failure generates inaccuracies and biases in inventories and can compromise comparability among international LCA studies. Our study introduces scale consistency as a principle for regionalized agri-food LCIs. We present a generic procedure that defines how scale-dependent LCI flows should be regionalized, depending on data availability. We then present a list of inventory flows that require regionalization and their suggested calculation procedures (methods and models) from 2 methodological guides developed by projects Agribalyse and World Food LCA Database. As proof of concept, we apply the procedure to Portugal and assess whether the methods and models proposed for each type of inventory flow in both guides can potentially be applied consistently with the data available. For 17 inventory flows, we apply calculated scale-consistent inventory flows for Portuguese agriculture, covering 260 products that can be used in future LCA studies. Comparing results with international databases, we show that this procedure can improve country-level estimates significantly. Our study is the first step in introducing scale consistency as a guiding principle for regionalized LCIs for agri-food LCA studies. Integr Environ Assess Manag 2017;13:939-951. © 2017 SETAC.