Fridolin Krausmann

Quantifying and mapping the human appropriation of net primary production in earth's terrestrial ecosystems

Human appropriation of net primary production (HANPP), the aggregate impact of land use on biomass available each year in ecosystems, is a prominent measure of the human domination of the biosphere. We present a comprehensive assessment of global HANPP based on vegetation modeling, agricultural and forestry statistics, and geographical information systems data on land use, land cover, and soil degradation that localizes human impact on ecosystems. We found an aggregate global HANPP value of 15.6 Pg C/yr or 23.8% of potential net primary productivity, of which 53% was contributed by harvest, 40% by land-use-induced productivity changes, and 7% by human-induced fires. This is a remarkable impact on the biosphere caused by just one species. We present maps quantifying human-induced changes in trophic energy flows in ecosystems that illustrate spatial patterns in the human domination of ecosystems, thus emphasizing land use as a pervasive factor of global importance. Land use transforms earths terrestrial surface, resulting in changes in biogeochemical cycles and in the ability of ecosystems to deliver services critical to human well being. The results suggest that large-scale schemes to substitute biomass for fossil fuels should be viewed cautiously because massive additional pressures on ecosystems might result from increased biomass harvest.

Socioeconomic legacy yields an invasion debt

Globalization and economic growth are widely recognized as important drivers of biological invasions. Consequently, there is an increasing need for governments to address the role of international trade in their strategies to prevent species introductions. However, many of the most problematic alien species are not recent arrivals but were introduced several decades ago. Hence, current patterns of alien-species richness may better reflect historical rather than contemporary human activities, a phenomenon which might be called “invasion debt.” Here, we show that across 10 taxonomic groups (vascular plants, bryophytes, fungi, birds, mammals, reptiles, amphibians, fish, terrestrial insects, and aquatic invertebrates) in 28 European countries, current numbers of alien species established in the wild are indeed more closely related to indicators of socioeconomic activity from the year 1900 than to those from 2000, although the majority of species introductions occurred during the second half of the 20th century. The strength of the historical signal varies among taxonomic groups, with those possessing good capabilities for dispersal (birds, insects) more strongly associated with recent socioeconomic drivers. Nevertheless, our results suggest a considerable historical legacy for the majority of the taxa analyzed. The consequences of the current high levels of socioeconomic activity on the extent of biological invasions will thus probably not be completely realized until several decades into the future.

Global human appropriation of net primary production doubled in the 20th century

Global increases in population, consumption, and gross domestic product raise concerns about the sustainability of the current and future use of natural resources. The human appropriation of net primary production (HANPP) provides a useful measure of human intervention into the biosphere. The productive capacity of land is appropriated by harvesting or burning biomass and by converting natural ecosystems to managed lands with lower productivity. This work analyzes trends in HANPP from 1910 to 2005 and finds that although human population has grown fourfold and economic output 17-fold, global HANPP has only doubled. Despite this increase in efficiency, HANPP has still risen from 6.9 Gt of carbon per y in 1910 to 14.8 GtC/y in 2005, i.e., from 13% to 25% of the net primary production of potential vegetation. Biomass harvested per capita and year has slightly declined despite growth in consumption because of a decline in reliance on bioenergy and higher conversion efficiencies of primary biomass to products. The rise in efficiency is overwhelmingly due to increased crop yields, albeit frequently associated with substantial ecological costs, such as fossil energy inputs, soil degradation, and biodiversity loss. If humans can maintain the past trend lines in efficiency gains, we estimate that HANPP might only grow to 27–29% by 2050, but providing large amounts of bioenergy could increase global HANPP to 44%. This result calls for caution in refocusing the energy economy on land-based resources and for strategies that foster the continuation of increases in land-use efficiency without excessively increasing ecological costs of intensification.

Methodology and Indicators of Economy-wide Material Flow Accounting

Summary This contribution presents the state of the art of economywide material flow accounting. Starting from a brief recollection of the intellectual and policy history of this approach, we outline system definition, key methodological assumptions, and derived indicators. The next section makes an effort to establish data reliability and uncertainty for a number of existing multinational (European and global) material flow accounting (MFA) data compilations and discusses sources of inconsistencies and variations for some indicators and trends. The results show that the methodology has reached a certain maturity: Coefficients of variation between databases lie in the range of 10% to 20%, and correlations between databases across countries amount to an average R 2 of 0.95. After discussing some of the research frontiers for further methodological development, we conclude that the material flow accounting framework and the data generated have reached a maturity that warrants material flow indicators to complement traditional economic and demographic information in providing a sound basis for discussing national and international policies for sustainable resource use.

How to calculate and interpret ecological footprints for long periods of time: the case of Austria 1926-1995

Abstract In this paper we present calculations of the ecological footprint (EF) for Austria 1926–1995, based upon three different methodological approaches. Basically, EF calculations convert the use of selected materials in a country into the area needed to sustain this material flow. Therefore, biological productivity essentially determines the outcome of EF calculations, given a certain pattern of socioeconomic metabolism. In most EF calculations published thus far, material and energy flows are converted to area (hectares) using global yields of the respective year. In contrast, we analyze the effect different assumptions on yields have on the results of EF calculations by assuming: (1) constant global yields as of 1995; (2) variable global yields; and (3) variable local yields for domestic extraction and variable global yields for imported biomass. Fossil-energy footprint is evaluated on the basis of constant carbon sequestration rates published by Wackernagel. According to our results different assumptions on yields can influence the result of EF calculations by a factor of 2, at least. We conclude that further research is necessary with respect to biomass yields assumed in EF calculations. The purpose for which EF calculations are made, and the interpretation of their results, will determine future development of the EF methodology.

A comprehensive global 5 min resolution land-use data set for the year 2000 consistent with national census data

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 Earths 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 set can be downloaded at http://www.iff.ac.at/socec/.

Land-use change and socio-economic metabolism in Austria—Part I: driving forces of land-use change: 1950–1995

Abstract This is an analysis of the relationships between changes in land use, land cover and socio-economic metabolism in Austria between 1950 and 1995, covering the period during which Austrias agriculture was industrialized. From 1950 to about 1980, Austria mainly strove to achieve self-sufficiency as an agricultural producer. This goal was met in the 1970s, largely through agricultural intensification. Since then, the primary focus of Austrian agricultural policy has been to reduce agricultural overproduction, to preserve the existing farm structure, as well as to keep as large an agricultural area under cultivation as is possible. As a consequence, since the 1980s yields rose slowly and subsidized fallow covered substantial parts of cropland area. Austria joined the European Union in 1995, after which agricultural policy was, to a large extent, determined by the EU Common Agricultural Policy. From 1950 to 1995 we observe a continuous trend of declining cropland and grassland areas, increases in the areas of built-up and infrastructure land, and a slow increase in forested areas. The segregation of cropland cultivation and livestock husbandry leads to a concentration of cropland in fertile lowlands and of grasslands in the lower alpine regions from which crops are retreating. As a result of livestock being fed increasing amounts of cropland produce and imported protein feedstuffs, there was a disintegration of local nutrient cycles and a rising input of mineral fertilizer. We interpret these changes as a consequence of the massive input of fossil energy into Austrias agricultural system, which allowed a surge in the intensification of transport. We analyze these trends using GIS maps based upon statistic data.

Global bioenergy potentials from agricultural land in 2050: Sensitivity to climate change, diets and yields

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.

How Circular is the Global Economy?: An Assessment of Material Flows, Waste Production, and Recycling in the European Union and the World in 2005

It is increasingly recognized that the growing metabolism of society is approaching limitations both with respect to sources for resource inputs and sinks for waste and emission outflows. The circular economy (CE) is a simple, but convincing, strategy, which aims at reducing both input of virgin materials and output of wastes by closing economic and ecological loops of resource flows. This article applies a sociometabolic approach to assess the circularity of global material flows. All societal material flows globally and in the European Union (EU‐27) are traced from extraction to disposal and presented for main material groups for 2005. Our estimate shows that while globally roughly 4 gigatonnes per year (Gt/yr) of waste materials are recycled, this flow is of moderate size compared to 62 Gt/yr of processed materials and outputs of 41 Gt/yr. The low degree of circularity has two main reasons: First, 44% of processed materials are used to provide energy and are thus not available for recycling. Second, socioeconomic stocks are still growing at a high rate with net additions to stocks of 17 Gt/yr. Despite having considerably higher end‐of‐life recycling rates in the EU, the overall degree of circularity is low for similar reasons. Our results indicate that strategies targeting the output side (end of pipe) are limited given present proportions of flows, whereas a shift to renewable energy, a significant reduction of societal stock growth, and decisive eco‐design are required to advance toward a CE.

Land use and industrial modernization: an empirical analysis of human influence on the functioning of ecosystems in Austria 1830–1995

Abstract This paper discusses changes in the functioning of terrestrial ecosystems caused by land use. It presents an empirical analysis of changes in land use, agricultural productivity, and socio-economic biomass metabolism in Austria during the 19th and 20th centuries, related to the process of “industrial modernization”, i.e. the transition from a society relying entirely on solar energy to the industrial society of today based on fossil fuel use. The development of “human appropriation of net primary production” in connection with the changes in the socio-economic energy system are discussed for the period 1830–1995.