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The future bioenergy crop potential depends on (1) changes in the food system (food demand, agricultural technology), (2) political stability and investment security, (3) biodiversity conservation, (4) avoidance of long carbon payback times from deforestation, and (5) energy crop yields. Using a biophysical biomass-balance model, we analyze how these factors affect global primary bioenergy potentials in 2050. The model calculates biomass supply and demand balances for eleven world regions, eleven food categories, seven food crop types and two livestock categories, integrating agricultural forecasts and scenarios with a consistent global land use and NPP database. The TREND scenario results in a global primary bioenergy potential of 77 EJ/yr, alternative assumptions on food-system changes result in a range of 26–141 EJ/yr. Exclusion of areas for biodiversity conservation and inaccessible land in failed states reduces the bioenergy potential by up to 45%. Optimistic assumptions on future energy crop yields increase the potential by up to 48%, while pessimistic assumptions lower the potential by 26%. We conclude that the design of sustainable bioenergy crop production policies needs to resolve difficult trade-offs such as food vs. energy supply, renewable energy vs. biodiversity conservation or yield growth vs. reduction of environmental problems of intensive agriculture., Highlights ► Global energy crop potentials in 2050 are calculated with a biophysical biomass-balance model. ► The study is focused on dedicated energy crops, forestry and residues are excluded. ► Depending on food-system change, global energy crop potentials range from 26–141 EJ/yr. ► Exclusion of protected areas and failed states may reduce the potential up to 45%. ► The bioenergy potential may be 26% lower or 45% higher, depending on energy crop yields.

Research highlights ▶ Food demand, agricultural technology and conservation constrain bio-energy supply. ▶ Global bio-energy crop potentials in 2050 may be 44–133 EJ/yr. ▶ Total global primary bio-energy potentials in 2050 may be 160–270 EJ/yr., Bio-energy, that is, energy produced from organic non-fossil material of biological origin, is promoted as a substitute for non-renewable (e.g., fossil) energy to reduce greenhouse gas (GHG) emissions and dependency on energy imports. At present, global bio-energy use amounts to approximately 50 EJ/yr, about 10% of humanity's primary energy supply. We here review recent literature on the amount of bio-energy that could be supplied globally in 2050, given current expectations on technology, food demand and environmental targets (‘technical potential’). Recent studies span a large range of global bio-energy potentials from ≈30 to over 1000 EJ/yr. In our opinion, the high end of the range is implausible because of (1) overestimation of the area available for bio-energy crops due to insufficient consideration of constraints (e.g., area for food, feed or nature conservation) and (2) too high yield expectations resulting from extrapolation of plot-based studies to large, less productive areas. According to this review, the global technical primary bio-energy potential in 2050 is in the range of 160–270 EJ/yr if sustainability criteria are considered. The potential of bio-energy crops is at the lower end of previously published ranges, while residues from food production and forestry could provide significant amounts of energy based on an integrated optimization (‘cascade utilization’) of biomass flows.

Humanity's role in shaping patterns and processes in the terrestrial biosphere is large and growing. Most of the earth's fertile land is used more or less intensively by humans for resource extraction, production, transport, consumption and waste deposition or as living space. Biomass production on cropland, grazing areas and in managed forests dominates area requirements, but other processes such as soil degradation, human-induced fires and expansion of settlements and infrastructure play an increasingly important role as well. The growing human domination of terrestrial ecosystems contributes to biodiversity loss as well as to a reduced capability of ecosystems to deliver vital services such as buffering capacity, soil conservation or self-regulation. This special section is devoted to the presentation of recent research into the patterns, determinants and implications of the human appropriation of net primary production (HANPP), an integrated socio-ecological indicator of land use intensity. By measuring the combined effect of land conversion and biomass harvest on the availability of trophic energy (biomass) in ecosystems, HANPP explicitly links natural with socioeconomic processes and allows for integrated analyses of land systems. This introductory article explains the rationale that links current HANPP research to Ecological Economics and discusses issues of definition and methods shared by all articles included in the special section. Finally, it gives an overview of the individual papers, provides some general conclusions and presents an outlook for future research: a better understanding of long-term trajectories of HANPP, of the significance of trade patterns as well as of the future role of bioenergy are highlighted as important issues to be addressed in the coming years.

Nation-level Ecological Footprint accounts are currently produced for more than 150 nations, with multiple calculations available for some nations. The data sets that result from these national assessments typically serve as the basis for Footprint calculations at smaller scales, including those for regions, cities, businesses, and individuals. Global Footprint Network's National Footprint Accounts, supported and used by more than 70 major organizations worldwide, contain the most widely used national accounting methodology today. The National Footprint Accounts calculations are undergoing continuous improvement as better data becomes available and new methodologies are developed. In this paper, a community of active Ecological Footprint practitioners and users propose key research priorities for improving national Ecological Footprint accounting. For each of the proposed improvements, we briefly review relevant literature, summarize the current state of debate, and suggest approaches for further development. The research agenda will serve as a reference for a large scale, international research program devoted to furthering the development of national Ecological Footprint accounting methodology. (C) 2008 Elsevier B.V. All rights reserved.

This article presents a medium resolution land use data set (5 arc min, c. 10 × 10 km) for the year 2000 that reproduces national land use statistics for cropland and forestry at the country level. We distinguish five land use classes displayed as percent-per-gridcell layers: cropland, grazing, forestry, urban and infrastructure areas, and areas without land use. For each gridcell, the sum of these five layers is 100%; that is, the Earth's total land area is allocated to these five classes. Spatial patterns are derived from available thematic maps and reconciled with national extents from census data. Statistical comparisons of the resulting maps with MODIS and CORINE data demonstrate the reliability of our data set; remaining discrepancies can be largely explained by the conceptual difference between land use and land cover. The data set presented here is aimed to support the systematic integration of socio-economic and ecological data in integrated analyses of the coupled global land system. The data se...

Land-use changes considerably alter the patterns and processes of terrestrial ecosystems. In an attempt to assess the impact of the human domination of ecosystems, this study quantifies the effect of human activities on aboveground carbon stocks in vegetation, based on a comparison of potential and actual vegetation in Austria. Following an accounting approach, statistical and GIS data on vegetation, elevation, land use, biomass harvest, as well as forest inventories and real estate statistics, were entered into the assessment, which was performed at the level of municipalities (n = 2,350). The results show that aboveground carbon storage in Austria has been considerably reduced by human activities. Actual vegetation contains 64% less carbon than would be expected in potential vegetation. The conversion of forests to cropland, grasslands, and urban areas has contributed 77% to this reduction in carbon stocks, the remaining 23% is due to forest management. In Austria, aboveground carbon stocks in forests have been reduced by 30% due to reductions in stand age and changes in forest species composition. Placing the data in a historical context, this analysis suggests that the current terrestrial carbon sink is a reversal of past carbon losses.

The fraction of total plant growth or net primary production (NPP) appropriated by humans, often referred to as human appropriation of net primary production (HANPP), is among the most widely used measures to assess the “human domination of Earth's ecosystems” ([1][1]). S. Rojstaczer et al. (“

Land use has greatly transformed Earth's surface. While spatial reconstructions of how the extent of land cover and land-use types have changed during the last century are available, much less information exists about changes in land-use intensity. In particular, global reconstructions that consistently cover land-use intensity across land-use types and ecosystems are missing. We, therefore, lack understanding of how changes in land-use intensity interfere with the natural processes in land systems. To address this research gap, we map land-cover and land-use intensity changes between 1910 and 2010 for 9 points in time. We rely on the indicator framework of human appropriation of net primary production (HANPP) to quantify and map land-use-induced alterations of the carbon flows in ecosystems. We find that, while at the global aggregate level HANPP growth slowed down during the century, the spatial dynamics of changes in HANPP were increasing, with the highest change rates observed in the most recent past. Across all biomes, the importance of changes in land-use areas has declined, with the exception of the tropical biomes. In contrast, increases in land-use intensity became the most important driver of HANPP across all biomes and settings. We conducted uncertainty analyses by modulating input data and assumptions, which indicate that the spatial patterns of land use and potential net primary production are the most critical factors, while spatial allocation rules and uncertainties in overall harvest values play a smaller role. Highlighting the increasing role of land-use intensity compared to changes in the areal extent of land uses, our study supports calls for better integration of the intensity dimension into global analyses and models. On top of that, we provide important empirical input for further analyses of the sustainability of the global land system.

There is a growing recognition that the interrelations between agriculture, food, bioenergy, and climate change have to be better understood in order to derive more realistic estimates of future bioenergy potentials. This article estimates global bioenergy potentials in the year 2050, following a “food first” approach. It presents integrated food, livestock, agriculture, and bioenergy scenarios for the year 2050 based on a consistent representation of FAO projections of future agricultural development in a global biomass balance model. The model discerns 11 regions, 10 crop aggregates, 2 livestock aggregates, and 10 food aggregates. It incorporates detailed accounts of land use, global net primary production (NPP) and its human appropriation as well as socioeconomic biomass flow balances for the year 2000 that are modified according to a set of scenario assumptions to derive the biomass potential for 2050. We calculate the amount of biomass required to feed humans and livestock, considering losses between biomass supply and provision of final products. Based on this biomass balance as well as on global land-use data, we evaluate the potential to grow bioenergy crops and estimate the residue potentials from cropland (forestry is outside the scope of this study). We assess the sensitivity of the biomass potential to assumptions on diets, agricultural yields, cropland expansion and climate change. We use the dynamic global vegetation model LPJmL to evaluate possible impacts of changes in temperature, precipitation, and elevated CO2 on agricultural yields. We find that the gross (primary) bioenergy potential ranges from 64 to 161 EJ y−1, depending on climate impact, yields and diet, while the dependency on cropland expansion is weak. We conclude that food requirements for a growing world population, in particular feed required for livestock, strongly influence bioenergy potentials, and that integrated approaches are needed to optimize food and bioenergy supply., Highlights ► We analyze the sensitivity of bioenergy potentials to diets, yields and climate change. ► Global bioenergy potentials in 2050 excluding forestry are 64-161 EJ y-1. ► Food and livestock feed requirements strongly influence bioenergy potentials. ► Food crop yields affect the area available for energy crops. ► Climate-change impacts on bioenergy potentials may be substantial but are highly uncertain.

Highlights • Land use intensification led to declining HANPP levels, while harvest increased. • Land system change was strikingly similar in the Italian North and South. • Levels of land use efficiency differed but trends were similar., Over the past centuries, land systems in Italy experienced fundamental shifts, owing to the availability of new energy forms, population surges, and technological progress. The 20th century was characterized by massive productivity increases, accompanied by gradual land abandonment and the return of forest land. We here analyze 120 years of land system change in Italy, applying the human appropriation of net primary production (HANPP) framework, a metric for socio-economic pressures on terrestrial ecosystems. HANPP allows integrating ecological with societal perspectives, by systematically quantifying (a) biomass harvest and (b) the difference between potential productivity of ecosystems and current productivity induced by land use processes, such as land conversion, or land degradation. Besides assessing national trends we calculated HANPP separately for the Italian North and South between 1934 and 2007, in order to scrutinize if high regional discrepancies in terms of natural and socio-economic preconditions translate into diverging land system trajectories. Our results show that national HANPP has been declining from 78% of natural productivity before WWII to 56% in 2007, indicating a declining land -use induced pressure on biomass flows over time. Simultaneously, biomass harvest increased by around 26% due to agricultural intensification, despite shrinking croplands. Although we found a significant difference between the Northern and Southern region in the absolute levels of several land use indicators related to biomass appropriation, the overarching trends of land system change were remarkably similar in both regions. This suggests that underlying drivers of land system change, such as policies aimed at land-use intensification and structural change were equally dominating land system trajectories in the North and South of Italy, not withstanding their socio-ecological divergences.

Additional file 1. Supplementary material.

Biomass carbon stocks (BCS) play a vital role in the climate system, but benchmarked estimates prior to the late 20th century remain scarce. Here, by making use of an early global forest resource assessment and harmonizing information on land use and carbon densities, we establish a global BCS account for the year 1950. Our best-guess BCS estimate is 450.7 PgC (median of all modulations: 518.3 PgC, range: 443.9-584.6 PgC), with ecosystems in Southern America and Western Africa storing c. 27 and 16% of the total respectively. Our estimates are in line with land change emissions estimates and suggest a reduction in BCS of 8-29% compared to the median, with losses in tropical subcontinents partially offset by gains in northern subcontinents. Our study demonstrates an approach to reconstruct global BCS over the 20th century to complement carbon flux-based modelling efforts and identify emerging global land transitions.

The role of ecosystems as carbon (C) sinks or sources is intrinsically related to land-use intensity, which determines the land required for biomass production. Here, we systematically investigate the role of different land-use types including their land-use intensities on vegetation C-stocks (SCact) in the Stubai valley, located in the Austrian central Alps. After a period of high land-use impacts until 1954, indicated by massive C-depletion, land-use shifted to completely new courses. Polarization into high-intensity low-land areas and extensification at higher altitudes allowed for a tripling of SCact until 2003. The most important land-use change was the intensification of the livestock sector accompanied by abandonment of extensive grasslands and reduced harvest pressure on forests after WWII. Market integration, abundance of fossil energy carriers, as well as structural change of the economy were important underlying socio-economic drivers of these trends. However, despite this remarkable SCact increase, SCact amounted to only 62% of the potential carbon stocks (SCpot) in 2003. Although conversion of forests to agriculture clearly contributed the lion’s share to this SC-gap, forest management explains roughly one quarter of the SC-difference. We found that time-lags between land-use shifts and the establishment of a new C-climax had fundamental repercussions on recent C-dynamics in the study region. Apparently, the land system is still net-accumulating C, although land-use changes have peaked decades earlier. Our findings are crucial for the understanding of C-dynamics, including the role of land management and time-lags in mountainous regions, which are regarded key areas for terrestrial C-sequestration. Electronic supplementary material The online version of this article (doi:10.1007/s10021-017-0120-5) contains supplementary material, which is available to authorized users.

Geografisk Tidsskrift—Danish Journal of Geography 109(2):119–130, 2009 In our rapidly globalizing world economy activities in one region have increasingly important effects on ecological, economic or social processes elsewhere, an effect which we here denote as ‘teleconnections’ between different regions. Biomass trade, one of the causes behind such teleconnections, is currently growing exponentially. Integrated analyses of changes in the global land system are high on the agenda of sustainability science, but a methodological framework for a consistent allocation of environmental burdens related to the consumption and production of biomass between regions has not been put forth to date. The concept of the ‘embodied human appropriation of net primary production’ (abbreviated ‘embodied HANPP’ or ‘eHANPP’) allows for the assessment of the ‘upstream’ effects on ecosystem energetics associated with a particular level of biomass consumption or with a given biomass-based product. This concept is based ...

Recent plans to alter the Loliondo Game Controlled Area (GCA), a nature conservation area located in Northern Tanzania, would result in substantial reduction of rangelands in the region. We quantify the current and hypothetical levels of the aboveground Human Appropriation of Net Primary Production (aHANPP) in one of the affected villages, and estimate the maximum exploitability rate of rangelands by livestock in the region. We find that the current aHANPP of the village amounts to 34–38% of the potential productivity, which could increase to 59–67% due to the altered GCA. On rangelands, livestock-induced aHANPP would increase from the current level of 30–34% to 54–61%, which is far above a maximum exploitability rate of 40–41%. Our results reveal that the intended changes to the Loliondo GCA will severely affect the current livelihood strategy of the Maasai, which is based on pastoralism.

Recent plans to alter the Loliondo Game Controlled Area (GCA), a nature conservation area located in Northern Tanzania, would result in substantial reduction of rangelands in the region. We quantify the current and hypothetical levels of the aboveground Human Appropriation of Net Primary Production (aHANPP) in one of the affected villages, and estimate the maximum exploitability rate of rangelands by livestock in the region. We find that the current aHANPP of the village amounts to 34–38% of the potential productivity, which could increase to 59–67% due to the altered GCA. On rangelands, livestock-induced aHANPP would increase from the current level of 30–34% to 54–61%, which is far above a maximum exploitability rate of 40–41%. Our results reveal that the intended changes to the Loliondo GCA will severely affect the current livelihood strategy of the Maasai, which is based on pastoralism.

Additional file 1. Supplementary material.

Agroecology has been proposed as a strategy to improve food system sustainability, but has also been criticised for using land inefficiently. We compared five explorative storylines, developed in a stakeholder process, for future food systems in the EU to 2050. We modelled a range of biophysical (e.g., land use and food production), environmental (e.g., greenhouse gas emissions) and social indicators, and potential for regional food self-sufficiency, and investigated the economic policy needed to reach these futures by 2050. Two contrasting storylines for upscaling agroecological practices emerged. In one, agroecology was implemented to produce high-value products serving high-income consumers through trade but, despite 40% of agricultural area being under organic management, only two out of eight EU environmental policy targets were met. As diets followed current trends in this storyline, there were few improvements in environmental indicators compared with the current situation, despite large-scale implementation of agroecological farming practices. This suggests that large-scale implementation of agroecological practices without concurrent changes on the demand side could aggravate existing environmental pressures. However, our second agroecological storyline showed that if large-scale diffusion of agroecological farming practices were implemented alongside drastic dietary change and waste reductions, major improvements on environmental indicators could be achieved and all relevant EU policy targets met. An alternative storyline comprising sustainable intensification in combination with dietary change and waste reductions was efficient in meeting targets related to climate, biodiversity, ammonia emissions, and use of antibiotics, but did not meet targets for reductions in pesticide and fertiliser use. These results confirm the importance of dietary change for food system climate change mitigation. Economic modelling showed a need for drastic changes in consumer preferences towards more plant-based, agroecological and local foods, and for improvements in technology, for these storylines to be realised, as very high taxes and tariffs would otherwise be needed.

Agriculture contributes to deforestation and the conversion of other terrestrial ecosystems, affecting important ecosystem functions. A growing share of the produced agricultural commodities is traded between countries. It is widely assumed that international trade reduces humanity’s pressure on land ecosystems by optimizing the mix of origin, i.e. by sourcing products from countries where land is used more efficiently. We examined if recent changes in the origin of agricultural products reduced humanity’s impact on a fundamental ecosystem function, the net primary production (NPP) of vegetation. We performed an index decomposition analysis on a dataset of human appropriation of net primary production embodied in bilateral trade flows of 392 agricultural products between 167 countries (eHANPP) from 1986 to 2011. We found that while changes in the origin of agricultural products globally reduced HANPP in the 1990s, this trend reversed since 1999. This turn is explained by the increased sourcing of agricultural products from tropical regions, for exports and domestic consumption. After 2008, countries – on average – increasingly sourced their agricultural products from less efficient regions than in 1986. Our results suggest that the potential of trade to reduce humanity’s impact on land ecosystems has not been exploited in the recent past.

Close to 40% of Earth’s land area is used for agriculture to provide humankind with plant- and animal-based food, fibers or bioenergy. Future trends in agricultural land use, livestock husbandry and associated environmental pressures are determined by developments in the food sector, agricultural productivity, technology, and many other influencing factors. Scenario analysis helps to understand their complex interaction and obtain quantitative insight. We here present an in-depth description of the agricultural land use model BioBaM-GHG 2.0 (“BioBaM”), designed for evaluating large numbers of agricultural and livestock production scenarios assembled on the basis of exogenous assumptions on food systems, crop yields and other factors. BioBaM determines the feasibility of specific parameter combinations and the corresponding greenhouse gas (GHG) emissions from agricultural activities, livestock husbandry, land-use change and other activities. We provide a description of the software environment, the model’s data structures, input and output variables and model algorithms. To illustrate the model’s capabilities and the scope of model applications, we describe two exemplary studies performed with BioBaM: We assess implications of agro-ecological innovations and the feasibility of their widespread application in order to illustrate their implications in terms of agricultural self-sufficiency and GHG emissions. This first case study aligns a small number of individual scenarios with qualitative storylines. We also showcase a ”biophysical option space approach”, which represents a comprehensive sensitivity analysis regarding the multidimensional uncertainties inherent to main influencing parameters, i.e. projections for diets and yields; assumptions on cropland use for bioenergy, and regarding grassland intensification. The global potential of forest regeneration for climate change mitigation serves as an example for this second approach. The option space comprises 90 scenarios and encompasses the full range of literature estimates on GHG mitigation from afforestation in 2050 (0.5 – 7 Gt CO2/yr). It further shows that the potential is zero under certain diet-yieldcombinations. Assuming zero energy crop cultivation and global convergence to a healthy reference diet, the sequestration potential of afforestation rises to 10 Gt CO2/yr in 2050. These exemplary applications illustrate how option spaces developed with BioBaM can complement scenario-based assessments that usually focus on small numbers of individual scenarios: Option spaces shift attention to a wider scope of conceivable futures and thus support a comprehensive view on systemic relations and dependencies, whereas analyses with few scenarios allow apprehension of much more detailed scenario narratives and qualifications.