Under pressure: Environmental Impact of Agriculture

Agriculture and food consumption are  identified as one of the most important drivers of environmental pressures, especially habitat change, climate change, water use and toxic emissions. (UNEP 2010, P.13)

One of the (many) reasons why I decided to focus on agriculture, was its significance from a sustainability point of view. We know that there is something seriously wrong with the way our industry and lifestyle is impacting nature. I believe that as a ‘knowing’ and ‘sentient’ human being somehow I have the duty to –at least try- to contribute to a more sustainable world. The first step is understanding what the nature of the impact is, and to identify the key drivers of change…in the next step one can focus on the points of leverage, policies that bring change.


Ranking products, activities and materials according to their environmental and resource impacts helps direct policy to those areas that really matter.’

Since Agriculture is so important to human culture and live, it should be no surprise that agriculture is one of the most  ‘important  drivers of environmental pressures,  especially habitat change, climate change,  water use and toxic emissions.’ (UNEP 2010, p.13)

In its impressive overview report the UNEP International Panel for Sustainable Resource Management (Resource Panel) assess how different economic activities influence the use of natural resources and the generation of pollution: UNEP (2010) Assessing the Environmental Impacts of Consumption and Production: Priority Products and Materials,

The report answers this question in two steps :                                                                First, as a preliminary step the panel reviewed the work that assesses the importance of observed pressures and impacts on the Earth’s Natural system (usually divided into ecological health, human health, and resources provision capability).         Second, the report investigates the causation of these pressures by different economic activities.

1. Diagnosis of ecological health of ecosystems.

The panel considers the 2005 Millennium Ecosystem Assessment (MA)  to be the most authoritative analyis with regard the status of global ecosystems. Over 1,300 scientists from all parts of the world contributed to the MA. The MA identifies factors that threaten ecosystems and contributions of ecosystems to human well-being (Mooney et al. 2005). The MA found that over the past 50 years humans have changed ecosystems more rapidly and extensively than in any comparable time period in human history, largely to meet rapidly growing demand for food, fresh water, timber, fibre and fuel. This has resulted in a substantial and largely irreversible loss in the diversity of life on Earth. Priority environmental pressures identified by the MA are

-habitat change,                                                                                                             -pollution with nitrogen and phosphorus,                                                                           -overexploitation of biotic resources such as fisheries and forests,                                   -climate change, and                                                                                                     – invasive species.

On a finite planet, the supply of food, water, energy, land and materials is limited, which creates competition among uses and users.First, materials get used up as a result of their consumption by humans. Second, the amount of resources available is limited compared to the potential demand of a growing and increasingly affluent society                                                                                                                             The main components in the category of biotic resources from nature are fish, game, forest biomass and pasture biomass. The Millennium Ecosystem Assessment has identified the overexploitation of these resources as one of the most important pressures on biodiversity (Mooney et al. 2005).

2. Which production drivers are creating most significant pressure?

The report focuses on these type of pressures identified as responsible for the most significant environmental impact: Emissions of greenhouse gas (GHG); Emissions of eutrophying substances; Emissions of toxic substances; Extraction of abiotic resources; Extraction of biotic resources; and Use of land and fresh water. In this blogpost I’ll provide you with some key graphs, sometimes the graphs speak for themselves; text is added where considered necessary.

2.1. Emissions of Green house gases (you know the ones that are contributing to climat change…)

2.2 Emissions of eutrophying substances

Figure 3.4 shows that production of electricity and various agricultural outputs are the largest contributors to eutrophication. NOx emissions from power plants cause terrestrial eutrophication and due to the sheer amount of emissions, electrical utilities are ranked first according to the method and data used. The emitters ranked second to fifth are fertilizer uses.

In a recent report of McKinsey  Resource Revolution: Meeting the world’s energy, materials, food, and water. (November 2011) the interference with the global phosphorus and nitrogen cycle is linked the rise of demand of certain type of agricultural inputs . Increased nitrogen and phosphorus consumption has potentially negative effects on the environment and human health. The increased use of fertilizer in agriculture has been a primary driver of the increased use of phosphorus and nitrogen around the world. The EuropeanNitrogen Assessment identifies five key societal areas threatened by nitrogen fertilizers: water quality, air quality, greenhouse balance, ecosystems and biodiversity, and soil quality. Air pollution by nitrogen oxides and ammonia not only increases the level of chemicals that can cause respiratory problems and cancers for humans but can also damage crops and vegetation. Furthermore, atmospheric nitrogen deposition may encourage certain plants to outcompete sensitive species, leading to biodiversity issues. (P.56 Mckinsey)

2.3. Emissions of toxic substances

Agricultural activities were identified as the major contributors of ecotoxic impacts, cotton being by far the largest contributor according to the method and data used. The use of agrochemicals was the main reason that agricultural activities are ranked high. In cotton production, for instance, aldicarb, cypermethrin and parathion-meth­yl were identified as the main issues, while metolachlor, atrazine and cyanazine were identified as the main contributor for feed grains (Suh 2008).

The results should be interpreted with a caution, as they are bound by the limitations of the methodology and the uncertainty of data used. (See p. 40 of UNEP 2010 for further details)

2.4. Extraction of biotic resources

Agriculture is the most important anthropogenic activity responsible for terrestrial biotic resource extraction, producing 2121.6 million tonnes of grain, 391.6 million tonnes of oilseed and 120.5 million tonnes of cotton globally in 2008 (USDA 2009). Wood harvesting is another important activity for terrestrial biotic resources extraction, accounting for 1.55 billion m3 of wood annually (FAO, 2008).

This use of biotic resources is not by necessity problematic. Yet, when harvested above sustainable levels, this can endanger the reproduction of the resources.

2.5. Use of land and fresh water

Water use is an important environmental pressure in various parts of the world. Agriculture is by far the most important use: over 70% of the global freshwater consumption is used in that sector (see e.g. Hoekstra and Chapagain 2008; Koehler 2009).

Agriculture is also the most important user of land. According to the FAO database, about 38% of the total world’s land area is used for agriculture in 2007. (FAOSTAT resource database, land use data accessible at http://faostat.fao.org/site/377/default.aspx, accessed 10 April 2010.)


In a next stage the several drivers and pressures of agriculture will be analysed in more depth. Next to this the main focus of this blog will be to look for alternatives, as you can guess the author of this blog believes that organic agriculture or agro-ecology will be the solution…


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