Consequences of human modification of the global nitrogen cycle
Tóm tắt
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 (N r ) to the environment. Many thresholds for human and ecosystem health have been exceeded owing to N r 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 N r can trigger a cascade of negative environmental impacts in sequence. Here, we provide an overview of the impact of N r on the environment and human health, including an assessment of the magnitude of different environmental problems, and the relative importance of N r as a contributor to each problem. In some cases, N r 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.
Từ khóa
Tài liệu tham khảo
Marschner H, 1995, Mineral nutrition of higher plants, 2, 889
Hatfield JL, 2008, Nitrogen in the environment: sources, problems, and management, 702
Smil V, 2001, Enriching the Earth, 338
WHO. 2003 Health aspects of air pollution with particulate matter ozone and nitrogen dioxide. Report on a WHO Working Group; Bonn Germany 13–15 January 2003. Copenhagen Denmark: WHO Regional Office for Europe.
WHO, 2006, WHO air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulphur dioxide, global update 2005: summary of risk assessment
WHO. 2008 Health risks of ozone form long-range transboundary air pollution. Report of World Health Organisation. Copenhagen Denmark; WHO Regional Office for Europe.
WHO. 2011 Global health observatory map gallery. http://www.who.int.
De Leeuw F& Horálek J. 2009 Assessment of the health impacts of exposure to PM2.5 at a European level. ETC/ACC technical paper2009/1. See http://air-climate.eionet.europa.eu/reports/#tp.
Mills G, 2011, Ozone pollution: a hidden threat to food security
European Environment Agency (EEA), 2005, The European environment: State and outlook 2005, 576
United Nations Environment Programme (UNEP), 2007, Global Environmental Outlook-4 (GEO-4)
WHO. 2007 Protein and amino acid requirements in human nutrition: report of a joint FAO/WHO/UNU expert consultation. WHO technical report series no. 935. Geneva Switzerland: WHO.
Selman M Sugg Z Greenhalgh S& Diaz R. 2008 Eutrophication and hypoxia in coastal areas: a global assessment of the state of knowledge. WRI Report (http://www.wri.org/publication/eutrophication-and-hypoxia-in-coastal-areas).
Vörösmarty M, 2005, Ecosystems and human well-being. Synthesis. A Report of the Millennium Ecosystem Assessment
Sherman K Aquarone M& Adams S. 2007 Global applications of the Large Marine Ecosystem concept 2007–2010. NOAA Technical Memorandum NMFS-NE-208. Narragansett RI USA: National Marine Fisheries Service.
IPCC, 2007, Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 976