Alexander F Bouwman

• Professor at Utrecht University

Freshwater pollution is, together with climate change, one of today’s most severe and pervasive threats to the global environment. Comprehensive and spatially explicit scenarios covering a wide range of constituents for freshwater quality are currently scarce. In this Global Perspective paper, we propose a novel model-based approach for five water...

The Green Revolution rapidly increased India’s food production since the 1960s, but excessive synthetic fertilizer use caused severe environmental problems. Our spatially explicit analysis for 1970–2020 indicates an uneven distribution of the dramatic increase of surpluses of India’s soil N (4.3 to 21.6 Tg N/year) and P budget (0.4 to 3.3 Tg P/year...

A spatially explicit (0.5 degree resolution) analysis is presented of the impact of human lifestyle, diet and nutrient use efficiency in food production and wastewater treatment on exceedance of threshold concentrations for nitrate in groundwater, and total N and total P concentrations in surface water, as well as criteria for their ratio. This ana...

Transforming the global food system is necessary to avoid exceeding planetary boundaries. A robust evidence base is crucial to assess the scale and combination of interventions required for a sustainable transformation. We developed a risk assessment framework, underpinned by a meta-regression of 60 global food system modeling studies, to quantify...

Cropland is a main source of global nitrogen pollution1,2. Mitigating nitrogen pollution from global croplands is a grand challenge because of the nature of non-point-source pollution from millions of farms and the constraints to implementing pollution-reduction measures, such as lack of financial resources and limited nitrogen-management knowledge...

Excessive agricultural nitrogen use causes environmental problems globally¹, to an extent that it has been suggested that a safe planetary boundary has been exceeded². Earlier estimates for the planetary nitrogen boundary3,4, however, did not account for the spatial variability in both ecosystems’ sensitivity to nitrogen pollution and agricultural...

Phosphorus (P) is an essential nutrient for life. In many tropical countries, P-fixing soils and very low historical P input limit uptake of P in crops and thus yields. This presents a serious obstacle for achieving the Sustainable Development Goal (SDG) target 2.3 of doubling productivity in smallholder farms. We calculated the geographic distribu...

This global spatially explicit (0.5 by 0.5 degree) analysis presents the nitrogen (N) and phosphorus (P) inputs, processing and biogeochemical retention and delivery to surface waters and river export to coastal seas according to the five shared socioeconomic pathways (SSP). Four systems are considered: (i) human system; (ii) agriculture; (iii) aqu...

The SSP (Shared Socio-economic Pathways) scenarios are intensively used in climate and environmental research to explore uncertain future developments and possible response strategies. This paper briefly describes an update of the SSP scenarios generated by the IMAGE 3.2 model. The paper presents the changes in method and key scenario updates. As s...

Input–output estimates of nitrogen on cropland are essential for improving nitrogen management and better understanding the global nitrogen cycle. Here, we compare 13 nitrogen budget datasets covering 115 countries and regions over 1961–2015. Although most datasets showed similar spatiotemporal patterns, some annual estimates varied widely among th...

Aquaculture policy often promotes production of low‐trophic level species for sustainable industry growth. Yet, the application of the trophic level concept to aquaculture is complex, and its value for assessing sustainability is further complicated by continual reformulation of feeds. The majority of fed farmed fish and invertebrate species are pr...

The three large marine ecosystems (LMEs) bordering China (Yellow Sea/Bohai Sea, East China Sea, and South China Sea) have received excess nitrogen (N) and phosphorus (P) in the past decades with detrimental consequences for ecosystem functioning, such as increased productivity, loss of biodiversity, and proliferation of harmful algal blooms (HABs)....

Large-scale commercialization of the Haber-Bosch (HB) process is resulting in intensification of nitrogen (N) fertilizer use worldwide. Globally N fertilizer use is far outpacing that of phosphorus (P) fertilizer. Much of the increase in N fertilizers is also now in the form of urea, a reduced form of N. Incorporation of these fertilizers into agri...

Abstract Over the last centuries, human activities have exerted increasing pressures on the environment, leading to drastic alterations in the functioning of freshwater bodies (e.g., eutrophication). Global biogeochemical models have proven crucial to investigate interactions between humans, hydrology, and water quality of surface fresh waters. How...

Abstract Symptoms of eutrophication (including biodiversity loss, harmful algal blooms, and hypoxia) are an increasing problem in Chinese seas. Nutrient enrichment is primarily caused by accelerated human activities that cause nutrient pollution of the aquatic environment. In this study, the Integrated Model to Assess the Global Environment–Global...

Nitrous oxide (N2O), like carbon dioxide, is a long-lived greenhouse gas that accumulates in the atmosphere. Over the past 150 years, increasing atmospheric N2O concentrations have contributed to stratospheric ozone depletion¹ and climate change², with the current rate of increase estimated at 2 per cent per decade. Existing national inventories do...

This paper presents an incubation experiment with sediment cores from the Changjiang Estuary Mud Area (CEMA) to quantify the release of nutrients due to simulated resuspension. The results show that except for nitrate (NO3--N), phosphate (PO43--P), ammonium (NH4+-N), nitrite (NO2--N) and silicate (SiO32--Si) were released from the sediment to the o...

Hypoxia is a mounting problem affecting the world’s coastal waters, with severe consequences for marine ecosystems. Coastal oxygen consumption has been increasing, mainly owing to the continued spread nutrient discharges. Using field observations, incubation experiments and numerical modeling, we studied the spatial and temporal variability of diss...

Dissolved carbon (C) leaching in and from soils plays an important role in C transport along the terrestrial-aquatic continuum. However, a global overview and analysis of dissolved carbon in soil solutions, covering a wide range of vegetation types and climates, is lacking. We compiled a global database on annual average dissolved organic carbon (D...

This paper presents the spatially explicit (0.5 degree spatial resolution) DISC-SILICON module, which is part of the IMAGE-DGNM global nutrient cycling framework. This new model for the first time enables to integrate the combined impact of long-term changes in land use, climate and hydrology on Si sources (weathering, sewage and soil loss) and sin...

Feeding a growing, increasingly affluent population while limiting environmental pressures of food production is a central challenge for society. Understanding the location and magnitude of food production is key to addressing this challenge because pressures vary substantially across food production types. Applying data and models from life cycle...

Humanity's transformation of the nitrogen cycle has major consequences for ecosystems, climate and human health, making it one of the key environmental issues of our time. Understanding how trends could evolve over the course of the 21st century is crucial for scientists and decision-makers from local to global scales. Scenario analysis is the prim...

The composition and accumulation of BSi and its role in C sequestration in the YRDW were quantified based on field investigation combined with remote sensing observation in the Yellow River Delta Wetland (YRDW). Results show that the soil BSi pool in the YRDW mainly consists of phytoliths. The pools of BSi, TOC, and BSi-occluded C (OCBSi) for above...

Dissolved carbon leaching in and from soils plays an important role in C transport along the terrestrial-aquatic continuum. However, a global overview and analysis of dissolved carbon in soil solutions, covering a wide range of vegetation types and climates, is lacking. We compiled a global database on annual average dissolved organic carbon (DOC)...

The transport of dissolved carbon in water leaching from soils to groundwater, and further to surface waters, may play an important role in connecting the terrestrial and aquatic carbon budgets. However, it has not been previously quantified on a global scale. Therefore large uncertainties remain regarding the size, drivers and global distribution...

Food production hinges largely upon access to phosphorus (P) fertilizer. Most fertilizer P used in the global agricultural system comes from mining of nonrenewable phosphate rock deposits located within few countries. However, P contained in livestock manure or urban wastes represents a recyclable source of P. To inform development of P recycling t...

This paper presents global estimates of nutrient discharge from households to surface water based on the relationships between income and human emissions represented by protein consumption, degree of connection to sewerage systems, presence of wastewater treatment plants and their level of nutrient removal efficiency. These relationships were used...

Salinisation can have different adverse impacts on water resources that are used for drinking, irrigation, or industrial purposes. In addition, salinisation in its turn is also strongly influenced by anthropogenic activities such as irrigation. This paper maps trade-offs between water quality (SDG 6.3) and other Sustainable Development Goals (SDGs)...

Global pork production has increased fourfold over the last 50 years and is expected to continue growing during the next three decades. This may have considerable implications for feed use, land requirements, and nitrogen emissions. To analyze the development of the pig production sector at the scale of world regions, we developed the IMAGE-Pig mod...

Plain Language Summary Improving food security in Sub‐Saharan Africa over the coming decades requires a dramatic increase in agricultural yields. Global yield increase has been driven by, among other factors, the widespread use of fertilizers including phosphorus. The use of fertilizers in Sub‐Saharan Africa is often prohibitively expensive, and th...

Although the Three Gorges Reservoir (TGR) is the largest man-made lake in the Changjiang River, it traps only a small fraction of the nitrogen (N) and dissolved silicate (DSi) inflows. Internal dissolution processes of exogenous biogenic silica (BSi) to DSi within TGR may control the overall silica (Si) retention, while the primary diatom productio...

This data article provides the data of Phosphorus emissions from laundry and dishwasher detergents as part of the Phosphorus emissions from households. The household emissions are presented in the research article “Global nitrogen and phosphorus in urban waste water based on the Shared Socio-economic pathway” (van Puijenbroek et al., 2019) [1]. Lau...

Understanding and mitigating the effects of phosphorus (P) overenrichment of waters globally, including the evaluation of the global Sustainability Development Goals, requires the use of global models. Such models quantitatively link land use, global population growth and climate to aquatic nutrient loading and biogeochemical cycling. Here we descr...

Nitrogen (N) and phosphorus (P) flows from land to sea in the Yangtze River basin were simulated for the period 1900–2010, by combining models for hydrology, nutrient input to surface water, and an in-stream retention. This study reveals that the basin-wide nutrient budget, delivery to surface water, and in-stream retention increased during this pe...

Understanding how cities can transform organic waste into a valuable resource is critical to urban sustainability. The capture and recycling of phosphorus (P), and other essential nutrients, from human excreta is particularly important as an alternative organic fertilizer source for agriculture. However, the complex set of socio-environmental facto...

The spatial distribution of reactive silica (RSi) and organic carbon (OC) in the Bohai Sea was determined on the basis of field measurements, and budgets were calculated with support from literature data. The riverine input, primary production and water exchange between the Bohai Sea and Yellow Sea have a strong effect on the distributions of RSi a...

A spatially explicit, two-pool soil phosphorus (P) model was used to analyze cropland P dynamics and fertilizer demand based on future crop production as projected in the shared socioeconomic pathways (SSPs). The model was initialized with historical data on P inputs and uptake, which governed the soil P accumulation up to present day. In contrast...

The Core Research Project on HABs in Eutrophic Systems was one of the projects implemented under the Global Ecology and Oceanography of Harmful Algal Blooms (GEOHAB) program. Building on several Open Science Meetings and associated international efforts, this project focused on a number of key questions that related to the types of harmful algal sp...

Globally, nutrient loading to surface waters is large and increasing, with sources from land-based pollution to aquaculture and atmospheric deposition. Spatial differences in amounts and forms of nutrients released to receiving waters are large, with Asia, Western Europe, and North America exporting the highest loads of nutrients, especially of ino...

The transport of dissolved carbon in water leaching from soils to groundwater may play an important role in connecting the terrestrial and aquatic carbon budgets. However, it has not been previously quantified on a global scale. Therefore large uncertainties remain regarding the size and drivers of the dissolved carbon flux from soil solution to gr...

Reactive nitrogen (N) inputs in agriculture strongly outpace the outputs at the global scale due to inefficiencies in cropland N use. While improvement in agricultural practices and environmental legislation in developed regions such as Western Europe have led to a remarkable increase in the N use efficiency since 1985, this lower requirement for...

Grassland management affects the carbon fluxes of one-third of the global land area and is thus an important factor for the global carbon budget. Nonetheless, this aspect has been largely neglected or underrepresented in global carbon cycle models. We investigate four harvesting schemes for the managed grassland implementation of the dynamic global...

Nitrogen (N) and phosphorus (P) play a major role in the biogeochemical functioning of aquatic systems. N and P transfer to surface freshwaters has amplified during the 20th century, which has led to widespread eutrophication problems. The contribution of different sources, natural and anthropogenic, to total N and P loading to river networks has r...

Early results and analysis of a database (yet in development) on yearly average values of dissolved carbon in soil porewater. First early results are shown for a range of climate zones and soil classes.

This study analyzes the influence of various fertilizer management practices on crop yield and soil organic carbon (SOC) based on the long-term field observations and modelling. Data covering 11 years from 8 long-term field trials were included, representing a range of typical soil, climate, and agro-ecosystems in China. The process-based model EPI...

By 2050 the global population will be 9.7 billion, placing an unprecedented burden on the world’s soils to produce extremely high food yields. Phosphorus (P) is crucial to plant growth and mineral fertilizer is added to soil to maintain P concentrations, however this is a finite resource, thus efficient use is critical. Plants primarily uptake P fr...

Phosphorus (P) plays a vital role in global crop production and food security. In this study, we investigate the changes in soil P pool inventories calibrated from historical countrywide crop P uptake, using a 0.5-by-0.5∘ spatially explicit model for the period 1900–2010. Globally, the total P pool per hectare increased rapidly between 1900 and 201...

Dam construction in river systems affects the biogeochemistry of nitrogen (N), yet most studies on N cycling in reservoirs do not consider the transformations and retention of the different N species. This study addresses the N inputs, transport, transformations, and retention in the Three Gorges Reservoir (TGR) in the Changjiang River, the world l...

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Grassland management directly affects the carbon fluxes of large areas and is thus an important factor for the global carbon budget. Nonetheless, this aspect has been largely ignored or underrepresented in global carbon cycle models. We introduce three different management schemes for the managed grassland implementation of the DGVM LPJmL that faci...

In recent decades farmers in high-income countries and China and India have built up a large reserve of residual soil P in cropland. This reserve can now be used by crops, and in high-income countries the use of mineral P fertilizer has recently been decreasing with even negative soil P budgets in Europe. In contrast to P, much of N surpluses are e...

Phosphorus (P) availability in soils limits crop yields in many regions of the world, while excess of soil P triggers aquatic eutrophication in other regions. Numerous processes drive the global spatial distribution of P in agricultural soils, but their relative roles remain unclear. Here, we combined several global datasets describing these driver...

Phosphorus (P) plays a vital role in global crop production and food security. In this study, we investigate the changes in soil P pools and crop P uptake, using a 0.5 by 0.5 degree spatially explicit model for the period 1900–2010. The simulated country-scale crop P uptake agrees well with historical P uptake. Simulated crop P uptake is influenced...

p>Many recent reviews and meta-analyses of N₂O emissions do not include data from Mediterranean studies. In this paper we present a meta-analysis of the N₂O emissions from Mediterranean cropping systems, and propose a more robust and reliable regional emission factor (EF) for N₂O, distinguishing the effects of water...

Many recent reviews and meta-analyses of N2O emissions do not include data from Mediterranean studies. In this paper we present a meta-analysis of the N2O emissions from Mediterranean cropping systems, and propose a more robust and reliable regional emission factor (EF) for N2O, distinguishing the effects of water management, crop type, and fertili...

Silicon (Si) is essential for growth of diatoms and other siliceous organisms, and plays a key role in marine ecosystems. We established a Si budget for the Bohai Sea and Yellow Sea (BSYS) on the basis of dissolved silicate (DSi) and biogenic silica (BSi) concentration measurements in two major rivers and in the water column and sediment of BSYS, a...

Nitrogen (N) limits crop and grass production, and it is an essential component of dietary proteins. However,N is mobile in the soil-plant system and can be lost to the environment. Estimates of N flows provide a critical tool for understanding and improving the sustainability and equity of the global food system. This letter describes an integrate...

Emissions of air pollutants such as sulfur and nitrogen oxides and particulates have significant health impacts as well as effects on natural and anthropogenic ecosystems. These same emissions also can change atmospheric chemistry and the planetary energy balance, thereby impacting global and regional climate. Long-term scenarios for air pollutant...

This paper describes the possible developments in global energy use and production, land use, emissions and climate changes following the SSP1 storyline, a development consistent with the green growth (or sustainable development) paradigm (a more inclusive development respecting environmental boundaries). The results are based on the implementation...

Various human activities – including agriculture, water consumption, river damming, and aquaculture – have intensified over the last century. This has had a major impact on nitrogen (N) and phosphorus (P) cycling in global continental waters. In this study, we use a coupled nutrient-input–hydrology–in-stream nutrient retention model to quantitative...

Grasslands provide grass and fodder to sustain the growing need for ruminant meat and milk. Soil nutrients in grasslands are removed through withdrawal in these livestock products and through animal manure that originates from grasslands and is spread in croplands. This leads to loss of soil fertility, because globally most grasslands receive no mi...

Silicon (Si) and carbon (C) play key roles in the river and marine biogeochemistry. The Si and C budgets for the Bohai Sea were established on the basis of measurements at a range of stations and additional data from the literature. The results show that the spatial distributions of reactive Si and organic C (OC) in the water column are largely aff...