Mitigation of nitrous oxide emissions from food production in China
Ma, L. ; Velthof, G.L. ; Kroeze, C. ; Ju, X. ; Hu, C. ; Oenema, O. ; Zhang, F. - \ 2014
Current Opinion in Environmental Sustainability 9-10 (2014). - ISSN 1877-3435 - p. 82 - 89.
greenhouse-gas emissions - reactive nitrogen - environmental-quality - nutrient management - climate-change - n2o emissions - croplands - chain - phosphorus - security
We evaluate nitrogen (N) management options to mitigate nitrous oxide (N2O) emissions from food production in China. First, we review approaches to quantify N2O emissions. We argue that long-term monitoring of N2O measurements at different sites is needed to improve emission estimates. Next, past trends in N2O emissions from food production are evaluated showing that N2O emissions more than doubled in China between 1980 and 2005. In the future, N2O emissions may continue to increase. However, combinations of diet changes, balanced fertilization and integrated nutrient management options can reduce N2O emission by almost two-thirds, relative to a business-as-usual scenario. We argue that further research and policy instruments for N2O reductions are needed on managing N in the food chain in order to ensure N2O emission reduction.
Nitrous Oxide (N2O) emissions from human waste in 1970-2050
Strokal, M. ; Kroeze, C. - \ 2014
Current Opinion in Environmental Sustainability 9-10 (2014). - ISSN 1877-3435 - p. 108 - 121.
water treatment-plant - coastal waters - climate-change - future-trends - sewage-sludge - anthropogenic nitrogen - reactive nitrogen - nutrient export - surface-water - united-states
Nitrous oxide (N2O) is an important contributor to climate change. Human waste is an important source of N2O emissions in several world regions, and its share in global emissions may increase in the future. In this paper we, therefore, address N2O emission from human waste: collected (from treatment and from sewage discharges) and uncollected waste. We review existing literature on emissions and emission factors, and present region-specific estimates of N2O emissions and their past and future trends. We show that human waste may became an important source of N2O emissions in the coming years as a result of increasing urbanization. About two-thirds of the global emissions are from uncollected waste, and about half from South Asia. We argue that more research is needed to improve emission factors.
Changes in wet nitrogen deposition in the United States between 1985 and 2012
Du, E. ; Vries, W. de; Galloway, J.N. ; Hu, X. ; Fang, J. - \ 2014
Environmental Research Letters 9 (2014). - ISSN 1748-9326 - 8 p.
precipitation chemistry - ammonia emissions - reactive nitrogen - reduced nitrogen - critical loads - trends - environment - future - usa
The United States (US) is among the global hotspots of nitrogen (N) deposition and assessing the temporal trends of wet N deposition is relevant to quantify the effectiveness of existing N regulation policies and its consequent environmental effects. This study analyzed changes in observed wet deposition of dissolved inorganic N (DIN = ammonium + nitrate) in the US between 1985 and 2012 by applying a Mann–Kendall test and Regional Kendall test. Current wet DIN deposition (2011–2012) data were used to gain insight in the current pattern of N deposition. Wet DIN deposition generally decreased going from Midwest > Northeast > South > West region with a national mean rate of 3.5 kg N ha-1 yr-1. Ammonium dominated wet DIN deposition in the Midwest, South and West regions, whereas nitrate and ammonium both contributed a half in the Northeast region. Wet DIN deposition showed no significant change at the national scale between 1985 and 2012, but profound changes occurred in its components. Wet ammonium deposition showed a significant increasing trend at national scale (0.013 kg N ha-1 yr-2), with the highest increase in the Midwest and eastern part of the South region. Inversely, wet nitrate deposition decreased significantly at national scale (-0.014 kg N ha-1 yr-2), with the largest reduction in the Northeast region. Overall, ratios of ammonium versus nitrate in wet deposition showed a significant increase in all the four regions, resulting in a transition of the dominant N species from nitrate to ammonium. Distinct magnitudes, trends and patterns of wet ammonium and nitrate deposition suggest the needs to control N emissions by species and regions to avoid negative effects of N deposition on ecosystem health and function in the US.
Nitrogen Footprint in China: Food, Energy, and Nonfood Goods
Gu, B.J. ; Leach, A.M. ; Ma, L. ; Galloway, J.N. ; Chang, S.X. ; Ge, Y. ; Chang, J. - \ 2013
Environmental Science and Technology 47 (2013)16. - ISSN 0013-936X - p. 9217 - 9224.
ecological footprint - livestock production - reactive nitrogen - recent trends - systems - tracking - cycle
The nitrogen (N) footprint is a novel approach to quantify losses to the environment of reactive N (Nr; all species of N except N-2) derived from human activities. However, current N footprint models are difficult to apply to new countries due to the large data requirement, and sources of Nr included in calculating the N footprint are often incomplete. In this study, we comprehensively quantified the N footprint in China with an N mass balance approach. Results show that the per capita N footprint in China increased 68% between 1980 and 2008, from 19 to 32 kg N yr(-1). The Nr loss from the production and consumption of food was the largest component of the N footprint (70%) while energy and nonfood products made up the remainder in approximately equal portion in 2008. In contrast, in 1980, the food-related N footprint accounted for 86% of the overall N footprint, followed by nonfood products (8%) and energy (6%). The findings and methods of this study are generally comparable to that of the consumer-based analysis of the N-Calculator. This work provides policy makers quantitative information about the sources of China's N footprint and demonstrates the significant challenges in reducing Nr loss to the environment.
Environmental Assessment of Management Options for Nutrient Flows in the Food Chain in China
Ma, L. ; Wang, F. ; Zhang, W. ; Ma, W. ; Velthof, G.L. ; Qin, W. ; Oenema, O. ; Zhang, F. - \ 2013
Environmental Science and Technology 47 (2013)13. - ISSN 0013-936X - p. 7260 - 7268.
global phosphorus flows - crop system management - integrated assessment - reactive nitrogen - future-trends - agriculture - consumption - losses - perspective - security
The nitrogen (N) and phosphorus (P) costs of food production have increased greatly in China during the last 30 years, leading to eutrophication of surface waters, nitrate leaching to groundwater, and greenhouse gas emissions. Here, we present the results of scenario analyses in which possible changes in food production–consumption in China for the year 2030 were explored. Changes in food chain structure, improvements in technology and management, and combinations of these on food supply and environmental quality were analyzed with the NUFER model. In the business as usual scenario, N and P fertilizer consumption in 2030 will be driven by population growth and diet changes and will both increase by 25%. N and P losses will increase by 44 and 73%, respectively, relative to the reference year 2005. Scenarios with increased imports of animal products and feed instead of domestic production, and with changes in the human diet, indicate reductions in fertilizer consumption and N and P losses relative to the business as usual scenario. Implementation of a package of integrated nutrient management measures may roughly nullify the increases in losses in the business as usual scenario and may greatly increase the efficiency of N and P throughout the whole food chain.
Consequences of human modification of the global nitrogen cycle
Erisman, J.W. ; Galloway, J. ; Seitzinger, S. ; Bleeker, A. ; Dise, N.B. ; Roxana Petrescu, A.M. ; Leach, A.M. ; Vries, W. de - \ 2013
Philosophical Transactions of the Royal Society B. Biological sciences 368 (2013)1621. - ISSN 0962-8436 - 9 p.
aquatic ecosystems - reactive nitrogen - climate-change - ozone - pollution - impact - policy - growth - oxide
The demand for more food is increasing fertilizer and land use, and the demand for more energy is increasing fossil fuel combustion, leading to enhanced losses of reactive nitrogen (Nr) to the environment. Many thresholds for human and ecosystem health have been exceeded owing to Nr pollution, including those for drinking water (nitrates), air quality (smog, particulate matter, ground-level ozone), freshwater eutrophication, biodiversity loss, stratospheric ozone depletion, climate change and coastal ecosystems (dead zones). Each of these environmental effects can be magnified by the ‘nitrogen cascade’: a single atom of Nr can trigger a cascade of negative environmental impacts in sequence. Here, we provide an overview of the impact of Nr on the environment and human health, including an assessment of the magnitude of different environmental problems, and the relative importance of Nr as a contributor to each problem. In some cases, Nr loss to the environment is the key driver of effects (e.g. terrestrial and coastal eutrophication, nitrous oxide emissions), whereas in some other situations nitrogen represents a key contributor exacerbating a wider problem (e.g. freshwater pollution, biodiversity loss). In this way, the central role of nitrogen can remain hidden, even though it actually underpins many trans-boundary pollution problems.
Assessing planetary and regional nitrogen boundaries related to food security and adverse environmental impacts
Vries, W. de; Kros, J. ; Kroeze, C. ; Seitzinger, S.P. - \ 2013
Current Opinion in Environmental Sustainability 5 (2013)3-4. - ISSN 1877-3435 - p. 392 - 402.
critical loads - climate-change - forest ecosystems - reactive nitrogen - global assessment - european forests - deposition - nutrient - world - consequences
This paper first describes the concept of, governance interest in, and criticism on planetary boundaries, specifically with respect to the nitrogen (N) cycle. These criticisms are then systematically evaluated. We argue that planetary N boundaries should include both the benefits and adverse impacts of reactive N (Nr) and the spatial variability of Nr impacts. We revise the planetary N boundary by considering the need to: first, avoid adverse impacts of elevated Nr emissions to water, air and soils, and second, feed the world population in an adequate way. The derivation of a planetary N boundary, in terms of anthropogenic fixation of di-nitrogen (N2) is illustrated by first, identification of multiple threat N indicators and setting limits for them; second, back calculating N losses from critical limits for N indicators, while accounting for the spatial variability of these indicators and their exceedance; and third, back calculating N fixation rates from critical N losses. The derivation of the needed planetary N fixation is assessed from the global population, the recommended dietary N consumption per capita and the N use efficiency in the complete chain from N fixation to N consumption. The example applications show that the previously suggested planetary N boundary of 35 Tg N yr-1 is too low in view of needed N fixation and also unnecessary low in view of most environmental impacts.
The links between global carbon, water and nutrient cycles in an urbanizing world — the case of coastal eutrophication
Kroeze, C. ; Hofstra, N. ; Ivens, W. ; Löhr, A. ; Strokal, M. ; Wijnen, J. van - \ 2013
Current Opinion in Environmental Sustainability 5 (2013)6. - ISSN 1877-3435 - p. 566 - 572.
climate-change - surface-water - reactive nitrogen - rivers - boundaries - planetary - impacts - system - land - consequences
The natural cycles of carbon (C), nitrogen (N), phosphorus (P) and water have been disturbed substantially by human activities. Urbanizing coastal drainage basins and large river deltas are located at the interface of freshwater and coastal components of the larger earth system and the process of urbanization is increasingly affecting these cycles. We take coastal water pollution as an example to illustrate this. To ensure sustainable development of urban-dominated water systems, future research challenges must include studies of the effects of the urbanization process on biogeochemical cycles that firstly, account for feedbacks and tipping points at the global scale; secondly, link to the Sustainability Development Goals; and finally, link to other forms of pollution. Urban coastal systems are of particular interest when exploring human–water–nutrient cycle interactions, and effective solutions for environmental and health problems associated with these interactions.
Modeling global nutrient export from watersheds
Kroeze, C. ; Bouwman, A.F. ; Seitzinger, S. - \ 2012
Current Opinion in Environmental Sustainability 4 (2012)2. - ISSN 1877-3435 - p. 195 - 202.
gulf-of-mexico - riverstrahler model - sampling frequency - reactive nitrogen - surface-water - river-systems - phosphorus - trends - ecosystems - budget
We describe how global models can be used to analyze past and future trends in nutrient export from watersheds and how such models can be used to analyze causes and effects of coastal eutrophication. Future nutrient inputs to coastal waters may be higher than today, and nutrient ratios may depart from Redfield ratios, but not in all world regions. We discuss the strengths and weaknesses of available nutrient export models. We argue that future global nutrient export models are preferably dynamic, distributed and mechanistic. There is a need for agricultural and sanitation policies aimed at reducing coastal eutrophication. More measurements of nutrients in rivers are needed, especially in the tropics.
Chemistry, transport and dry deposition of trace gases in the boundary layer over the tropical Atlantic Ocean and the Guyanas during the GABRIEL field campaign
Stickler, A. ; Fischer, H. ; Bozem, H. ; Gurk, C. ; Schiller, C. ; Martinez-Harder, M. ; Kubistin, D. ; Harder, H. ; Williams, J. ; Eerdekens, G. ; Yassaa, N. ; Ganzeveld, L.N. ; Sander, R. ; Lelieveld, J. - \ 2007
Atmospheric Chemistry and Physics 7 (2007). - ISSN 1680-7316 - p. 3933 - 3956.
automated fluorometric method - carbon-monoxide - atmospheric methane - molecular-hydrogen - coniferous forest - reactive nitrogen - upper troposphere - amazon-forest - climate model - rain-forest
We present a comparison of different Lagrangian and chemical box model calculations with measurement data obtained during the GABRIEL campaign over the tropical Atlantic Ocean and the Amazon rainforest in the Guyanas, October 2005. Lagrangian modelling of boundary layer (BL) air constrained by measurements is used to derive a horizontal gradient (¿5.6 pmol/mol km¿1) of CO from the ocean to the rainforest (east to west). This is significantly smaller than that derived from the measurements (16-48 pmol/mol km¿1), indicating that photochemical production from organic precursors alone cannot explain the observed strong gradient. It appears that HCHO is overestimated by the Lagrangian and chemical box models, which include dry deposition but not exchange with the free troposphere (FT). The relatively short lifetime of HCHO implies substantial BL-FT exchange. The mixing-in of FT air affected by African and South American biomass burning at an estimated rate of 0.12 h¿1 increases the CO and decreases the HCHO mixing ratios, improving agreement with measurements. A mean deposition velocity of 1.35 cm/s for H2O2 over the ocean as well as over the rainforest is deduced assuming BL-FT exchange adequate to the results for CO. The measured increase of the organic peroxides from the ocean to the rainforest (¿0.66 nmol/mol d¿1) is significantly overestimated by the Lagrangian model, even when using high values for the deposition velocity and the entrainment rate. Our results point at either heterogeneous loss of organic peroxides and/or their radical precursors, underestimated photodissociation or missing reaction paths of peroxy radicals not forming peroxides in isoprene chemistry. We calculate a mean integrated daytime net ozone production (NOP) in the BL of (0.2±5.9) nmol/mol (ocean) and (2.4±2.1) nmol/mol (rainforest). The NOP strongly correlates with NO and has a positive tendency in the boundary layer over the rainforest.