The environmental impact of agriculture varies based on the wide variety of agricultural practices employed around the world. Ultimately, the environmental impact depends on the production practices of the system used by farmers. The connection between emissions into the environment and the farming system is indirect, as it also depends on other climate variables such as rainfall and temperature. There are two types of indicators of environmental impact: "means-based", which is based on the farmer's production methods, and "effect-based", which is the impact that farming methods have on the farming system or on emissions to the environment. An example of a means-based indicator would be the quality of groundwater that is affected by the amount of
nitrogen applied to the
soil. An indicator reflecting the loss of nitrate to groundwater would be effect-based. The environmental impact of agriculture involves a variety of factors from the soil, to water, the air, animal and soil diversity, plants, and the food itself. Some of the environmental issues that are related to agriculture are
climate change,
deforestation, genetic engineering, irrigation problems, pollutants,
soil degradation, and
waste.
Fishing The environmental impact of fishing can be divided into issues that involve the availability of fish to be caught, such as
overfishing,
sustainable fisheries, and
fisheries management; and issues that involve the impact of fishing on other elements of the environment, such as
by-catch and destruction of habitat such as
coral reefs. According to the 2019
Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services report, overfishing is the main driver of mass species extinction in the oceans. These conservation issues are part of
marine conservation, and are addressed in
fisheries science programs. There is a growing gap between how many fish are available to be caught and humanity's desire to catch them, a problem that gets worse as the
world population grows. Similar to other
environmental issues, there can be conflict between the
fishermen who depend on fishing for their livelihoods and fishery scientists who realize that if future fish populations are to be
sustainable then some fisheries must reduce or even close. The journal
Science published a four-year study in November 2006, which predicted that, at prevailing trends, the world would run out of wild-caught seafood in 2048. The scientists stated that the decline was a result of
overfishing, pollution and other environmental factors that were reducing the population of fisheries at the same time as their ecosystems were being degraded. Yet again the analysis has met criticism as being fundamentally flawed, and many fishery management officials, industry representatives and scientists challenge the findings, although the debate continues. Many countries, such as Tonga, the United States, Australia and New Zealand, and international management bodies have taken steps to appropriately manage marine resources. The UN's Food and Agriculture Organization (FAO) released their biennial State of World Fisheries and Aquaculture in 2018 noting that capture fishery production has remained constant for the last two decades but unsustainable overfishing has increased to 33% of the world's fisheries. They also noted that aquaculture, the production of farmed fish, has increased from 120 million tonnes per year in 1990 to over 170 million tonnes in 2018. Populations of oceanic sharks and
rays have been reduced by 71% since 1970, largely due to overfishing. More than three-quarters of the species comprising this group are now threatened with extinction.
Irrigation The environmental impact of irrigation includes the changes in quantity and quality of
soil and water as a result of
irrigation and the ensuing effects on natural and social conditions at the tail-end and downstream of the irrigation scheme. The impacts stem from the changed
hydrological conditions owing to the installation and operation of the scheme. An irrigation scheme often draws water from the river and distributes it over the irrigated area. As a hydrological result it is found that: • the downstream river
discharge is reduced • the
evaporation in the scheme is increased • the
groundwater recharge in the scheme is increased • the level of the
water table rises • the
drainage flow is increased. These may be called direct effects. Effects on soil and
water quality are indirect and complex, and subsequent impacts on natural, ecological and
socio-economic conditions are intricate. In some, but not all instances,
water logging and
soil salinization can result. However, irrigation can also be used, together with soil drainage, to overcome soil salinization by leaching excess salts from the vicinity of the root zone. Irrigation can also be done extracting groundwater by
(tube)wells. As a hydrological result it is found that the level of the water descends. The effects may be
water mining, land/soil
subsidence, and, along the coast,
saltwater intrusion. Irrigation projects can have large benefits, but the negative side effects are often overlooked. Agricultural irrigation technologies such as high powered water pumps, dams, and pipelines are responsible for the large-scale depletion of fresh water resources such as aquifers, lakes, and rivers. As a result of this massive diversion of freshwater, lakes, rivers, and creeks are running dry, severely altering or stressing surrounding ecosystems, and contributing to the extinction of many aquatic species.
Agricultural land loss in California According to
UNESCO as of the year 2024, 75% of soils are degraded affecting 3.2 billion people. By the year 2050 the share of degraded land can rise to 90%, if current trends continue. During the years 2015-2019, around 100 million hectares of soil were degraded every year. Lal and Stewart estimated global loss of agricultural land by degradation and abandonment at 12 million hectares per year. In contrast, according to Scherr, GLASOD (Global Assessment of Human-Induced Soil Degradation, under the UN Environment Programme) estimated that 6 million hectares of agricultural land per year had been lost to soil degradation since the mid-1940s, and she noted that this magnitude is similar to earlier estimates by Dudal and by Rozanov et al. Such losses are attributable not only to
soil erosion, but also to salinization, loss of nutrients and organic matter, acidification, compaction, water logging and subsidence. Human-induced land degradation tends to be particularly serious in dry regions. Focusing on soil properties, Oldeman estimated that about 19 million square kilometers of global land area had been degraded; Dregne and Chou, who included degradation of vegetation cover as well as soil, estimated about 36 million square kilometers degraded in the world's dry regions. Despite estimated losses of agricultural land, the amount of arable land used in crop production globally increased by about 9% from 1961 to 2012, and is estimated to have been 1.396 billion hectares in 2012. Global average soil erosion rates are thought to be high, and erosion rates on conventional cropland generally exceed estimates of soil production rates, usually by more than an order of magnitude. In the US, sampling for erosion estimates by the US NRCS (Natural Resources Conservation Service) is statistically based, and estimation uses the Universal Soil Loss Equation and
Wind Erosion Equation. For 2010, annual average soil loss by sheet, rill and wind erosion on non-federal US land was estimated to be 10.7 t/ha on cropland and 1.9 t/ha on pasture land; the average soil erosion rate on US cropland had been reduced by about 34% since 1982. No-till and low-till practices have become increasingly common on North American cropland used for production of grains such as wheat and barley. On uncultivated cropland, the recent average total soil loss has been 2.2 t/ha per year. It is viewed as any change or
disturbance to the land perceived to be deleterious or undesirable. It is estimated that up to 40% of the world's agricultural land is seriously degraded.
Meat production . . Livestock domesticated by humans, as well as the biomass of humans themselves, constitute the other 96% of mammal biomass globally. ,
Democratic Republic of the Congo Environmental impacts associated with meat production include use of
fossil energy, water and land resources, greenhouse gas emissions, and in some instances, rainforest clearing,
water pollution and species endangerment, among other adverse effects. Steinfeld et al. of the FAO estimated that 18% of global anthropogenic GHG (greenhouse gas) emissions (estimated as 100-year carbon dioxide equivalents) are associated in some way with livestock production. Despite methane's 100-year
global warming potential, recently estimated at 28 without and 34 with climate-carbon feedbacks, Other anthropogenic GHG emissions associated with livestock production include carbon dioxide from fossil fuel consumption (mostly for production, harvesting and transport of feed), and nitrous oxide emissions associated with the use of nitrogenous fertilizers, growing of nitrogen-fixing legume vegetation and manure management. Management practices that can mitigate GHG emissions from production of livestock and feed have been identified. Considerable water use is associated with meat production, mostly because of water used in production of vegetation that provides feed. There are several published estimates of water use associated with livestock and meat production, but the amount of water use assignable to such production is seldom estimated. For example, "green water" use is evapotranspirational use of soil water that has been provided directly by precipitation; and "green water" has been estimated to account for 94% of global beef cattle production's "
water footprint", and on rangeland, as much as 99.5% of the water use associated with beef production is "green water". Impairment of water quality by manure and other substances in runoff and infiltrating water is a concern, especially where intensive livestock production is carried out. In the US, in a comparison of 32 industries, the livestock industry was found to have a relatively good record of compliance with environmental regulations pursuant to the Clean Water Act and Clean Air Act, but pollution issues from large livestock operations can sometimes be serious where violations occur. Various measures have been suggested by the US Environmental Protection Agency, among others, which can help reduce livestock damage to streamwater quality and riparian environments. Changes in livestock production practices influence the environmental impact of meat production, as illustrated by some beef data. In the US beef production system, practices prevailing in 2007 are estimated to have involved 8.6% less fossil fuel use, 16% less greenhouse gas emissions (estimated as 100-year carbon dioxide equivalents), 12% less withdrawn water use and 33% less land use, per unit mass of beef produced, than in 1977. From 1980 to 2012 in the US, while population increased by 38%, the small ruminant inventory decreased by 42%, the cattle-and-calves inventory decreased by 17%, and methane emissions from livestock decreased by 18%; Some impacts of meat-producing livestock
may be considered environmentally beneficial. These include waste reduction by conversion of human-inedible crop residues to food, use of livestock as an alternative to herbicides for control of invasive and noxious weeds and other vegetation management, use of animal manure as fertilizer as a substitute for those synthetic fertilizers that require considerable fossil fuel use for manufacture, grazing use for wildlife habitat enhancement, and carbon sequestration in response to grazing practices, among others. Conversely, according to some studies appearing in peer-reviewed journals, the growing demand for meat is contributing to
significant biodiversity loss as it is a significant driver of
deforestation and habitat destruction. Moreover, the 2019
Global Assessment Report on Biodiversity and Ecosystem Services by
IPBES also warns that ever increasing land use for meat production plays a significant role in biodiversity loss. A 2006
Food and Agriculture Organization report, ''
Livestock's Long Shadow'', found that around 26% of the planet's terrestrial surface is devoted to livestock grazing.
Palm oil Palm oil is a type of vegetable oil, found in oil palm trees, which are native to West and Central Africa. Initially used in foods in developing countries, palm oil is now also used in food, cosmetic and other types of products in other nations as well. Over one-third of vegetable oil consumed globally is palm oil.
Habitat loss The consumption of palm oil in food, domestic and cosmetic products all over the world means there is a high demand for it. To meet this, oil palm plantations are created, which means removing natural forests to clear space. This
deforestation has taken place in Asia, Latin America and West Africa, with Malaysia and Indonesia holding 90% of global oil palm trees. These forests are home to a wide range of species, including many
endangered animals, ranging from birds to rhinos and tigers. Since 2000, 47% of deforestation has been for the purpose of growing oil palm plantations, with around 877,000 acres being affected per year. This is not because of the oil palm itself, but rather because the oil palm is the only habitat provided in the plantations. The plantations are therefore known as a
monoculture, whereas natural forests contain a wide variety of flora and fauna, making them highly biodiverse. One of the ways palm oil could be made more
sustainable (although it is still not the best option) is through
agroforestry, whereby the plantations are made up of multiple types of plants used in trade – such as coffee or
cocoa. While these are more biodiverse than monoculture plantations, they are still not as effective as natural forests. In addition to this, agroforestry does not bring as many economic benefits to workers, their families and the surrounding areas.
Roundtable on Sustainable Palm Oil (RSPO) The RSPO is a non-profit organisation that has developed criteria that its members (of which, as of 2018, there are over 4,000) must follow to produce, source and use sustainable palm oil (Certified Sustainable Palm Oil; CSPO). Currently, 19% of global palm oil is certified by the RSPO as sustainable. The CSPO criteria states that oil palm plantations cannot be grown in the place of forests or other areas with endangered species, fragile ecosystems, or those that facilitate the needs of local communities. It also calls for a reduction in
pesticides and fires, along with several rules for ensuring the social wellbeing of workers and the local communities. == Ecosystem impacts ==