Human impact on the environment

Chart published by NASA depicting CO2 levels from the past 400,000 years.[24]

Overconsumption is a situation where resource use has outpaced the sustainable capacity of the ecosystem. It can be measured by the ecological footprint, a resource accounting approach which compares human demand on ecosystems with the amount of planet matter ecosystems can renew. Estimates indicate that humanity's current demand is 70%[25] higher than the regeneration rate of all of the planet's ecosystems combined. A prolonged pattern of overconsumption leads to environmental degradation and the eventual loss of resource bases.

Humanity's overall impact on the planet is affected by many factors, not just the raw number of people. Their lifestyle (including overall affluence and resource utilization) and the pollution they generate (including carbon footprint) are equally important. In 2008, The New York Times stated that the inhabitants of the developed nations of the world consume resources like oil and metals at a rate almost 32 times greater than those of the developing world, who make up the majority of the human population.[26]

Reduction of one's carbon footprint for various actions.

The effects of overpopulation are compounded by overconsumption. According to Paul R. Ehrlich, speaking in 2017:

Rich western countries are now siphoning up the planet’s resources and destroying its ecosystems at an unprecedented rate. We want to build highways across the Serengeti to get more rare earth minerals for our cellphones. We grab all the fish from the sea, wreck the coral reefs and put carbon dioxide into the atmosphere. We have triggered a major extinction event [...] A world population of around a billion would have an overall pro-life effect. This could be supported for many millennia and sustain many more human lives in the long term compared with our current uncontrolled growth and prospect of sudden collapse [...] If everyone consumed resources at the US level – which is what the world aspires to – you will need another four or five Earths. We are wrecking our planet’s life support systems.[27]

Human civilization has caused the loss of 83% of all wild mammals and half of plants.[28] The world's chickens are triple the weight of all the wild birds, while domesticated cattle and pigs outweigh all wild mammals by 14 to 1.[29][30] Global meat consumption is projected to more than double by 2050, perhaps as much as 76%, as the global population rises to more than 9 billion, which will be a significant driver of further biodiversity loss and increased GHG emissions.[31][32]

Human population from 10000 BCE to 2000 CE, with its exponential rise since the eighteenth century.[33]

David Attenborough described the level of human population on the planet as a multiplier of all other environmental problems.[34] In 2013, he described humanity as "a plague on the Earth" that needs to be controlled by limiting population growth.[35]

Some deep ecologists, such as the radical thinker and polemicist Pentti Linkola, see human overpopulation as a threat to the entire biosphere.[36] In 2017, over 15,000 scientists around the world issued a second warning to humanity which asserted that rapid human population growth is the "primary driver behind many ecological and even societal threats."[37] A 2021 report in Frontiers in Conservation Science warned that population size and growth are significant factors in biodiversity loss and soil degradation, adding that "more people means that more synthetic compounds and dangerous throwaway plastics are manufactured, many of which add to the growing toxification of the Earth. It also increases the chances of pandemics that fuel ever-more desperate hunts for scarce resources."[38][39]

Fishing down the foodweb

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.[41]

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.[42]

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.[43][44]

The UN's Food and Agriculture Organization (FAO) released their biennial State of World Fisheries and Aquaculture in 2018[45] 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.[46]

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.[47][48]

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.[49][50]

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.[51][52] 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.[53]

Urban sprawl in California

Soil erosion in Madagascar

Lal and Stewart estimated global loss of agricultural land by degradation and abandonment at 12 million hectares per year.[54] 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.[55] 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.[56] 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.[57] 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.[58]

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.[59] 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.[60] 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.[60] In comparison with agriculture using conventional cultivation, it has been suggested that, because no-till agriculture produces erosion rates much closer to soil production rates, it could provide a foundation for sustainable agriculture.[59]

Land degradation is a process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land.[61] It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable.[62] Natural hazards are excluded as a cause; however human activities can indirectly affect phenomena such as floods and bush fires. This is considered to be an important topic of the 21st century due to the implications land degradation has upon agronomic productivity, the environment, and its effects on food security.[63] It is estimated that up to 40% of the world's agricultural land is seriously degraded.[64]

Worldwide, the animal industry provides only 18% of calories, but uses 83% of agricultural land and emits 58% of food's greenhouse gas emissions.[65]

A village palm oil press "malaxeur" in Bandundu, 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.[67][68] 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.[67] FAO data indicate that meat accounted for 26% of global livestock product tonnage in 2011.[69]

Globally, enteric fermentation (mostly in ruminant livestock) accounts for about 27% of anthropogenic methane emissions,[70] Despite methane's 100-year global warming potential, recently estimated at 28 without and 34 with climate carbon feedbacks,[70] methane emission is currently contributing relatively little to global warming. Although reduction of methane emissions would have a rapid effect on warming, the expected effect would be small.[71] 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 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.[72][73][74][75][76]

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",[77] 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,[78] 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.[79]

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.[80] 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%;[58] yet despite the reduction in cattle numbers, US beef production increased over that period.[81]

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,[82] 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,[83] and carbon sequestration in response to grazing practices,[84][85] 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.[86][87][88][32] 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.[89][90] 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.[91]

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.[92]

The consumption of palm oil in food, domestic and cosmetic products all over the world means there is a high demand for it. In order 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.[93] Since 2000, 47% of deforestation has been for the purpose of growing oil palm plantations, with around 877,000 acres being affected per year.[92]

Natural forests are extremely biodiverse, with a wide range of organisms using them as their habitat. But oil palm plantations are the opposite. Studies have shown that oil palm plantations have less than 1% of the plant diversity seen in natural forests, and 47-90% less mammal diversity.[94] 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.[95]

The RSPO is a non-profit organisation that has developed a criteria that its members (of which, as of 2018, there are over 4,000) must follow in order 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.[96]

Child demonstrating for actions to protect the environment (2018)

Human activity is causing environmental degradation, which is the deterioration of the environment through depletion of resources such as air, water and soil; the destruction of ecosystems; habitat destruction; the extinction of wildlife; and pollution. It is defined as any change or disturbance to the environment perceived to be deleterious or undesirable.[62] As indicated by the I=PAT equation, environmental impact (I) or degradation is caused by the combination of an already very large and increasing human population (P), continually increasing economic growth or per capita affluence (A), and the application of resource-depleting and polluting technology (T).[97][98]

According to a 2018 study in Nature, 87% of the oceans and 77% of land (excluding Antarctica) have been altered by anthropogenic activity, and 23% of the planet's landmass remains as wilderness.[99]

Habitat fragmentation is the reduction of large tracts of habitat leading to habitat loss. Habitat fragmentation and loss are considered as being the main cause of the loss of biodiversity and degradation of the ecosystem all over the world. Human actions are greatly responsible for habitat fragmentation, and loss as these actions alter the connectivity and quality of habitats. Understanding the consequences of habitat fragmentation is important for the preservation of biodiversity and enhancing the functioning of the ecosystem.[100]

Both agricultural plants and animals depend on pollination for reproduction. Vegetables and fruits are an important diet for human beings and depend on pollination. Whenever there is habitat destruction, pollination is reduced and crop yield as well. Many pants also rely on animals and most especially those that eat fruit for seed dispersal. Therefore, the destruction of habitat for animal severely affects all the plant species that depend on them.[101]

Biodiversity generally refers to the variety and variability of life on Earth, and is represented by the number of different species there are on the planet. Since its introduction, Homo sapiens (the human species) has been killing off entire species either directly (such as through hunting) or indirectly (such as by destroying habitats), causing the extinction of species at an alarming rate. Humans are the cause of the current mass extinction, called the Holocene extinction, driving extinctions to 100 to 1000 times the normal background rate.[102][103] Though most experts agree that human beings have accelerated the rate of species extinction, some scholars have postulated without humans, the biodiversity of the Earth would grow at an exponential rate rather than decline.[2] The Holocene extinction continues, with meat consumption, overfishing, ocean acidification and the amphibian crisis being a few broader examples of an almost universal, cosmopolitan decline in biodiversity. Human overpopulation (and continued population growth) along with profligate consumption are considered to be the primary drivers of this rapid decline.[104][105] The 2017 World Scientists' Warning to Humanity stated that, among other things, this sixth extinction event unleashed by humanity could annihilate many current life forms and consign them to extinction by the end of this century.[37]

A June 2020 study published in PNAS argues that the contemporary extinction crisis "may be the most serious environmental threat to the persistence of civilization, because it is irreversible" and that its acceleration "is certain because of the still fast growth in human numbers and consumption rates."[106]

Summary of major biodiversity-related environmental-change categories expressed as a percentage of human-driven change (in red) relative to baseline (blue)

Defaunation is the loss of animals from ecological communities.[108]

It has been estimated that from 1970 to 2016, 68% of the world's wildlife has been destroyed due to human activity.[109][110] In South America, there is believed to be a 70 percent loss.[111] A May 2018 study published in PNAS found that 83% of wild mammals, 80% of marine mammals, 50% of plants and 15% of fish have been lost since the dawn of human civilization. Currently, livestock make up 60% of the biomass of all mammals on earth, followed by humans (36%) and wild mammals (4%).[28] According to the 2019 global biodiversity assessment by IPBES, human civilization has pushed one million species of plants and animals to the brink of extinction, with many of these projected to vanish over the next few decades.[89][112][113]

Whenever there is a decline in plant biodiversity, the remaining plants start to experience diminishing productivity. As a result, the loss of biodiversity continues being a threat to the productivity of the ecosystem all over the world, and this over ally impacts the natural ecosystem functioning.[114]

A 2019 report that assessed a total of 28,000 plant species concluded that close to half of them were facing a threat of extinction. The failure of noticing and appreciating plants is regarded as "plant blindness", and this is a worrying trend as it puts more plants at the threat of extinction than animals. Our increased farming has come at a higher cost to plant biodiversity as half of the habitable land on Earth is used for agriculture, and this is one of the major reasons behind the plant extinction crisis.[115]

Introductions of species, particularly plants into new areas, by whatever means and for whatever reasons have brought about major and permanent changes to the environment over large areas. Examples include the introduction of Caulerpa taxifolia into the Mediterranean, the introduction of oat species into the California grasslands, and the introduction of privet, kudzu, and purple loosestrife to North America. Rats, cats, and goats have radically altered biodiversity in many islands. Additionally, introductions have resulted in genetic changes to native fauna where interbreeding has taken place, as with buffalo with domestic cattle, and wolves with domestic dogs.

A major coral bleaching event took place on this part of the Great Barrier Reef in Australia

Because of human overpopulation, coral reefs are dying around the world.[116] In particular, coral mining, pollution (organic and non-organic), overfishing, blast fishing and the digging of canals and access into islands and bays are serious threats to these ecosystems. Coral reefs also face high dangers from pollution, diseases, destructive fishing practices and warming oceans.[117][118] In order to find answers for these problems, researchers study the various factors that impact reefs. The list of factors is long, including the ocean's role as a carbon dioxide sink, atmospheric changes, ultraviolet light, ocean acidification, biological virus, impacts of dust storms carrying agents to far flung reefs, pollutants, algal blooms and others. Reefs are threatened well beyond coastal areas.

General estimates show approximately 10% world's coral reefs are already dead.[119][120][121] It is estimated that about 60% of the world's reefs are at risk due to destructive, human-related activities. The threat to the health of reefs is particularly strong in Southeast Asia, where 80% of reefs are endangered.

In 2016, the Earth experienced a marine heatwave, which scientists have said resulted in the loss of coral over by 30% on the Great Barrier Reef between March and November 2016 alone. Many temperature-sensitive corals died immediately, and most others experienced bleaching to some extent. Despite this, after eight months further observation showed that <1% of the reef colonies that survived were still bleached.[122] With the Earth's temperature continuing to rise, and an increase in the frequency and intensity of weather phenomenons such as heatwaves, it is possible that coral reefs will continue to be affected these issues.

Domestic, industrial and agricultural wastewater makes its way to wastewater plants for treatment before being released into aquatic ecosystems. Wastewater at these treatment plants contains a cocktail of different chemical and biological contaminants which may influence surrounding ecosystems. For example, the nutrient rich water supports large populations of pollutant-tolerant Chironomidae, which in-turn attract insectivorous bats.[123] These insects accumulate toxins in their exoskeletons and pass them on to insectivorous birds and bats. As a result, metals may accumulate in the tissues and organs of these animals,[124] resulting in DNA damage,[123] and histopathological lesions.[125] Furthermore, this altered diet of fat-rich prey may cause changes in energy storage[126] and hormone production,[127] which may have significant impacts on torpor, reproduction, metabolism and survival.

Biological contaminants such as bacteria, viruses and fungi in wastewater can also be transferred to the surrounding ecosystem. Insects emerging from this wastewater may spread pathogens to nearby water sources. Pathogens, shed from humans, can be passed from this wastewater to organisms foraging at these treatment plants. This may lead to bacterial and viral infections or microbiome dysbiosis.

The fossils that are burned by humans for energy usually come back to them in the form of acid rain. Acid rain is a form of precipitation which has high sulfuric and nitric acids which can occur in the form of a fog or snow. Acid rain has numerous ecological impacts on streams, lakes, wetlands and other aquatic environments. It damages forests, robs the soil of its essential nutrients, releases aluminium to the soil, which makes it very hard for trees to absorb water.[130]

Researchers have discovered that kelp, eelgrass and other vegetation can effectively absorb carbon dioxide and hence reducing ocean acidity. Scientists, therefore, say that growing these plants could help in mitigating the damaging effects of acidification on marine life.[131]

Ozone depletion damages plants all over the world and this includes both the plants in the natural ecosystems and the agricultural crops. It damages vegetation by entering through the leaf's stomata and burning that plant tissue during the respiration process.[132] Ground-level ozone is known for causing more plant damage than any other all the combination of all other air pollutants.

Reduced ozone levels due to ozone depletion indicate that there is less protection from sun rays and more exposure to UVB radiation at the surface of the Earth. UVB radiation affects the developmental and physiological processes of plants. These effects include changes in plant form, the timing of developmental phases, distribution of nutrients within the plant and secondary metabolism.[133]

Of particular concern is N₂O, which has an average atmospheric lifetime of 114–120 years,[134] and is 300 times more effective than CO₂ as a greenhouse gas.[135] NO_x produced by industrial processes, automobiles and agricultural fertilization and NH₃ emitted from soils (i.e., as an additional byproduct of nitrification)[135] and livestock operations are transported to downwind ecosystems, influencing N cycling and nutrient losses. Six major effects of NO_x and NH₃ emissions have been identified:[136]

1. decreased atmospheric visibility due to ammonium aerosols (fine particulate matter [PM])
2. elevated ozone concentrations
3. ozone and PM affects human health (e.g. respiratory diseases, cancer)
4. increases in radiative forcing and global warming
5. decreased agricultural productivity due to ozone deposition
6. ecosystem acidification[137] and eutrophication.

The environmental impact of biodiesel includes energy use, greenhouse gas emissions and some other kinds of pollution. A joint life cycle analysis by the US Department of Agriculture and the US Department of Energy found that substituting 100% biodiesel for petroleum diesel in buses reduced life cycle consumption of petroleum by 95%. Biodiesel reduced net emissions of carbon dioxide by 78.45%, compared with petroleum diesel. In urban buses, biodiesel reduced particulate emissions 32 percent, carbon monoxide emissions 35 percent, and emissions of sulfur oxides 8%, relative to life cycle emissions associated with use of petroleum diesel. Life cycle emissions of hydrocarbons were 35% higher and emission of various nitrogen oxides (NOx) were 13.5% higher with biodiesel.[149] Life cycle analyses by the Argonne National Laboratory have indicated reduced fossil energy use and reduced greenhouse gas emissions with biodiesel, compared with petroleum diesel use.[150] Biodiesel derived from various vegetable oils (e.g. canola or soybean oil), is readily biodegradable in the environment compared with petroleum diesel.[151]

Smog in Beijing, China

The environmental impact of coal mining and -burning is diverse.[152] Legislation passed by the US Congress in 1990 required the United States Environmental Protection Agency (EPA) to issue a plan to alleviate toxic air pollution from coal-fired power plants. After delay and litigation, the EPA now has a court-imposed deadline of March 16, 2011, to issue its report.

The environmental impact of electricity generation is significant because modern society uses large amounts of electrical power. This power is normally generated at power plants that convert some other kind of energy into electricity. Each such system has advantages and disadvantages, but many of them pose environmental concerns.

Anti-nuclear protest near nuclear waste disposal centre at Gorleben in northern Germany

The environmental impact of nuclear power results from the nuclear fuel cycle processes including mining, processing, transporting and storing fuel and radioactive fuel waste. Released radioisotopes pose a health danger to human populations, animals and plants as radioactive particles enter organisms through various transmission routes.

Radiation is a carcinogen and causes numerous effects on living organisms and systems. The environmental impacts of nuclear power plant disasters such as the Chernobyl disaster, the Fukushima Daiichi nuclear disaster and the Three Mile Island accident, among others, persist indefinitely, though several other factors contributed to these events including improper management of fail safe systems and natural disasters putting uncommon stress on the generators. The radioactive decay rate of particles varies greatly, dependent upon the nuclear properties of a particular isotope. Radioactive Plutonium-244 has a half-life of 80.8 million years, which indicates the time duration required for half of a given sample to decay, though very little plutonium-244 is produced in the nuclear fuel cycle and lower half-life materials have lower activity thus giving off less dangerous radiation.[153]

Kiviõli Oil Shale Processing & Chemicals Plant in ida-Virumaa, Estonia

The environmental impact of the oil shale industry includes the consideration of issues such as land use, waste management, water and air pollution caused by the extraction and processing of oil shale. Surface mining of oil shale deposits causes the usual environmental impacts of open-pit mining. In addition, the combustion and thermal processing generate waste material, which must be disposed of, and harmful atmospheric emissions, including carbon dioxide, a major greenhouse gas. Experimental in-situ conversion processes and carbon capture and storage technologies may reduce some of these concerns in future, but may raise others, such as the pollution of groundwater.[154]

The environmental impact of petroleum is often negative because it is toxic to almost all forms of life. Petroleum, a common word for oil or natural gas, is closely linked to virtually all aspects of present society, especially for transportation and heating for both homes and for commercial activities.

The Wachusett Dam in Clinton, Massachusetts

The environmental impact of reservoirs is coming under ever increasing scrutiny as the world demand for water and energy increases and the number and size of reservoirs increases.

Dams and the reservoirs can be used to supply drinking water, generate hydroelectric power, increasing the water supply for irrigation, provide recreational opportunities and flood control. However, adverse environmental and sociological impacts have also been identified during and after many reservoir constructions. Although the impact varies greatly between different dams and reservoirs, common criticisms include preventing sea-run fish from reaching their historical mating grounds, less access to water downstream, and a smaller catch for fishing communities in the area. Advances in technology have provided solutions to many negative impacts of dams but these advances are often not viewed as worth investing in if not required by law or under the threat of fines. Whether reservoir projects are ultimately beneficial or detrimental—to both the environment and surrounding human populations— has been debated since the 1960s and probably long before that. In 1960 the construction of Llyn Celyn and the flooding of Capel Celyn provoked political uproar which continues to this day. More recently, the construction of Three Gorges Dam and other similar projects throughout Asia, Africa and Latin America have generated considerable environmental and political debate.

Wind turbines in an agricultural setting

Compared to the environmental impact of traditional energy sources, the environmental impact of wind power is relatively minor. Wind powered electricity generation consumes no fuel, and emits no air pollution, unlike fossil fuel power sources. The energy consumed to manufacture and transport the materials used to build a wind power plant is equal to the new energy produced by the plant within a few months. While a wind farm may cover a large area of land, many land uses such as agriculture are compatible, with only small areas of turbine foundations and infrastructure made unavailable for use.[155]

There are reports of bird and bat mortality at wind turbines, as there are around other artificial structures. The scale of the ecological impact may[156] or may not[157] be significant, depending on specific circumstances. Prevention and mitigation of wildlife fatalities, and protection of peat bogs,[158] affect the siting and operation of wind turbines.

There are conflicting reports about the effects of noise on people who live very close to a wind turbine.

The environmental impact of cleaning agents is diverse. In recent years, measures have been taken to reduce these effects.

Nanotechnology's environmental impact can be split into two aspects: the potential for nanotechnological innovations to help improve the environment, and the possibly novel type of pollution that nanotechnological materials might cause if released into the environment. As nanotechnology is an emerging field, there is great debate regarding to what extent industrial and commercial use of nanomaterials will affect organisms and ecosystems.

The environmental impact of paint is diverse. Traditional painting materials and processes can have harmful effects on the environment, including those from the use of lead and other additives. Measures can be taken to reduce environmental impact, including accurately estimating paint quantities so that wastage is minimized, use of paints, coatings, painting accessories and techniques that are environmentally preferred. The United States Environmental Protection Agency guidelines and Green Star ratings are some of the standards that can be applied.

A pulp and paper mill in New Brunswick, Canada. Although pulp and paper manufacturing requires large amounts of energy, a portion of it comes from burning wood waste.

The environmental impact of paper is significant, which has led to changes in industry and behaviour at both business and personal levels. With the use of modern technology such as the printing press and the highly mechanised harvesting of wood, paper has become a cheap commodity. This has led to a high level of consumption and waste. With the rise in environmental awareness due to the lobbying by environmental organizations and with increased government regulation there is now a trend towards sustainability in the pulp and paper industry.

Great Pacific garbage patch

Some scientists suggest that by 2050 there could be more plastic than fish in the oceans.[159] A December 2020 study published in Nature found that human-made materials, or anthropogenic mass, exceeds all living biomass on earth, with plastic alone outweighing the mass of all terrestrial and marine animals combined.[160][22]

The environmental impact of pesticides is often greater than what is intended by those who use them. Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, including nontarget species, air, water, bottom sediments, and food.[161] Pesticide contaminates land and water when it escapes from production sites and storage tanks, when it runs off from fields, when it is discarded, when it is sprayed aerially, and when it is sprayed into water to kill algae.[162]

The amount of pesticide that migrates from the intended application area is influenced by the particular chemical's properties: its propensity for binding to soil, its vapor pressure, its water solubility, and its resistance to being broken down over time.[163] Factors in the soil, such as its texture, its ability to retain water, and the amount of organic matter contained in it, also affect the amount of pesticide that will leave the area.[163] Some pesticides contribute to global warming and the depletion of the ozone layer.[164]

The environmental impact of pharmaceuticals and personal care products (PPCPs) is largely speculative. PPCPs are substances used by individuals for personal health or cosmetic reasons and the products used by agribusiness to boost growth or health of livestock. PPCPs have been detected in water bodies throughout the world. The effects of these chemicals on humans and the environment are not yet known, but to date there is no scientific evidence that they affect human health.[165]

The environmental impact of aviation occurs because aircraft engines emit noise, particulates, and gases which contribute to climate change[171][172] and global dimming.[173] Despite emission reductions from automobiles and more fuel-efficient and less polluting turbofan and turboprop engines, the rapid growth of air travel in recent years contributes to an increase in total pollution attributable to aviation. In the EU, greenhouse gas emissions from aviation increased by 87% between 1990 and 2006.[174] Among other factors leading to this phenomenon are the increasing number of hypermobile travellers[175] and social factors that are making air travel commonplace, such as frequent flyer programs.[175]

There is an ongoing debate about possible taxation of air travel and the inclusion of aviation in an emissions trading scheme, with a view to ensuring that the total external costs of aviation are taken into account.[176]

The environmental impact of roads includes the local effects of highways (public roads) such as on noise, light pollution, water pollution, habitat destruction/disturbance and local air quality; and the wider effects including climate change from vehicle emissions. The design, construction and management of roads, parking and other related facilities as well as the design and regulation of vehicles can change the impacts to varying degrees.

The environmental impact of shipping includes greenhouse gas emissions and oil pollution. In 2007, carbon dioxide emissions from shipping were estimated at 4 to 5% of the global total, and estimated by the International Maritime Organization (IMO) to rise by up to 72% by 2020 if no action is taken.[177] There is also a potential for introducing invasive species into new areas through shipping, usually by attaching themselves to the ship's hull.

The First Intersessional Meeting of the IMO Working Group on Greenhouse Gas Emissions[178] from Ships took place in Oslo, Norway on 23–27 June 2008. It was tasked with developing the technical basis for the reduction mechanisms that may form part of a future IMO regime to control greenhouse gas emissions from international shipping, and a draft of the actual reduction mechanisms themselves, for further consideration by IMO's Marine Environment Protection Committee (MEPC).[179]

In terms of carbon dioxide emissions, the fast fashion industry contributes between 4-5 billion tonnes per year, equating to 8-10% of total global emissions.[192] Carbon dioxide is a greenhouse gas, meaning it causes heat to get trapped in the atmosphere, rather than being released into space, raising the Earth's temperature - known as global warming.[193]

Alongside greenhouse gas emissions the industry is also responsible for almost 35% of microplastic pollution in the oceans.[192] Scientists have estimated that there are approximately 12-125 trillion tonnes of microplastic particles in the Earth's oceans.[194] These particles are ingested by marine organisms, including fish later eaten by humans.[195] The study states that many of the fibres found are likely to have come from clothing and other textiles, either from washing, or degradation.[195]

Textile waste is a huge issue for the environment, with around 2.1 billion tonnes of unsold or faulty clothing being disposed per year. Much of this is taken to landfill, but the majority of materials used to make clothes are not biodegradable, resulting in them breaking down and contaminating soil and water.[190]

Fashion, much like most other industries such as agriculture, requires a large volume of water for production. The rate and quantity at which clothing is produced in fast fashion means the industry uses 79 trillion litres of water every year.[192] Water consumption has proven to be very detrimental to the environment and its ecosystems, leading to water depletion and water scarcity. Not only do these affect marine organisms, but also human's food sources, such as crops.[196]