The Holocene extinction, or Anthropocene extinction, is the ongoing
extinction event
An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. I ...
during the
Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
epoch. The
extinction
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the Endling, last individual of the species, although the Functional ext ...
s span numerous families of
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...
,
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately fr ...
,
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae excl ...
s, and
animal
Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage ...
s, including
mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...
s,
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...
s,
reptile
Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates ( lizards and snakes) and rhynchocephalia ...
s,
amphibian
Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arbo ...
s,
fish
Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Included in this definition are the living hagfish, lampreys, and Chondrichthyes, cartilaginous and bony fish as we ...
,
invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chorda ...
s, and affecting not just terrestrial species but also large sectors of
marine life
Marine life, sea life, or ocean life is the plants, animals and other organisms that live in the salt water of seas or oceans, or the brackish water of coastal estuaries. At a fundamental level, marine life affects the nature of the planet. ...
. With widespread degradation of
biodiversity hotspots, such as
coral reef
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held together by calcium carbonate. Most coral reefs are built from stony corals, wh ...
s and
rainforest
Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...
s, as well as other areas, the vast majority of these extinctions are thought to be undocumented, as the species are undiscovered at the time of their extinction, which goes unrecorded. The current rate of extinction of species is estimated at 100 to 1,000 times higher than natural
background extinction rates,
and is increasing.
During the past 100–200 years, biodiversity loss and species extinction have accelerated,
to the point that most
conservation biologists now believe that
humankind
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
has either entered a period of mass extinction, or is on the cusp of doing so.
As such, the event has also been referred to as the sixth mass extinction or sixth extinction.
The Holocene extinction includes the disappearance of large land animals known as
megafauna
In terrestrial zoology, the megafauna (from Greek μέγας ''megas'' "large" and New Latin ''fauna'' "animal life") comprises the large or giant animals of an area, habitat, or geological period, extinct and/or extant. The most common thresho ...
, starting at the end of the
last glacial period. Megafauna outside of the
African mainland, which did not evolve alongside humans, proved highly sensitive to the introduction of human
predation
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
, and many died out shortly after early humans began spreading and hunting across the Earth.
Many
African species have also gone extinct in the Holocene, along with species in North America, South America, and Australia, but – with some exceptions – the megafauna of the Eurasian mainland was largely unaffected until a few hundred years ago. These extinctions, occurring near the
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
–
Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
boundary, are sometimes referred to as the
Quaternary extinction event.
The most popular theory is that human
overhunting
Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to replenish. The term ap ...
of species added to existing stress conditions as the Holocene extinction coincides with
human colonization of many new areas around the world. Although there is debate regarding how much human
predation
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
and
habitat loss
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
affected their decline, certain population declines have been directly correlated with the onset of human activity, such as the extinction events of
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...
and
Hawaii
Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...
. Aside from humans,
climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
may have been a driving factor in the megafaunal extinctions, especially at the end of the
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
.
In the
twentieth century, human numbers quadrupled, and the size of the global economy increased twenty-five-fold. This
Great Acceleration or
Anthropocene Epoch has also accelerated species extinction.
Ecologically, humanity is now an unprecedented "global superpredator",
which consistently preys on the adults of other
apex predators, takes over other species' essential habitats and displaces them,
and has
worldwide effects on
food webs. There have been extinctions of species on every
land mass
A landmass, or land mass, is a large region or area of land. The term is often used to refer to lands surrounded by an ocean or sea, such as a continent or a large island. In the field of geology, a landmass is a defined section of continent ...
and in every
ocean
The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wor ...
: there are many famous examples
within Africa,
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...
,
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
,
Australia
Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...
,
North
North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography.
Etymology
The word ''north ...
and
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...
, and on smaller islands.
Overall, the Holocene extinction can be linked to the
human impact on the environment
Human impact on the environment (or anthropogenic impact) refers to changes to biophysical environments and to ecosystems, biodiversity, and natural resources caused directly or indirectly by humans. Modifying the environment to fit the need ...
. The Holocene extinction continues into the
21st century
The 21st (twenty-first) century is the current century in the ''Anno Domini'' era or Common Era, under the Gregorian calendar. It began on 1 January 2001 ( MMI) and will end on 31 December 2100 ( MMC).
Marking the beginning of the 21st centur ...
, with
human population growth,
increasing per capita consumption,
and meat production, among others, being the primary drivers of mass extinction. Deforestation
Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated ...
, overfishing
Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in t ...
, ocean acidification
Ocean acidification is the reduction in the pH value of the Earth’s ocean. Between 1751 and 2021, the average pH value of the ocean surface has decreased from approximately 8.25 to 8.14. The root cause of ocean acidification is carbon dioxid ...
, the destruction of wetlands, and the decline in amphibian populations, among others, are a few broader examples of global biodiversity loss.
Background
Mass extinctions are characterized by the loss of at least 75% of species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
within a geologically short period of time. The Holocene extinction is also known as the "sixth extinction", as it is possibly the sixth mass extinction event, after the Ordovician–Silurian extinction events, the Late Devonian extinction
The Late Devonian extinction consisted of several extinction events in the Late Devonian Epoch, which collectively represent one of the five largest mass extinction events in the history of life on Earth. The term primarily refers to a major ex ...
, the Permian–Triassic extinction event
The Permian–Triassic (P–T, P–Tr) extinction event, also known as the Latest Permian extinction event, the End-Permian Extinction and colloquially as the Great Dying, formed the boundary between the Permian and Triassic geologic periods, ...
, the Triassic–Jurassic extinction event, and the Cretaceous–Paleogene extinction event
The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...
.
The Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
is the current geological epoch
In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured.
The moment of epoch is usually decided ...
.
Overview
There is no general agreement on where the Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
, or anthropogenic
Anthropogenic ("human" + "generating") is an adjective that may refer to:
* Anthropogeny, the study of the origins of humanity
Counterintuitively, anthropogenic may also refer to things that have been generated by humans, as follows:
* Human i ...
, extinction begins, and the Quaternary extinction event, which includes climate change resulting in the end of the last ice age, ends, or if they should be considered separate events at all. The Holocene extinction is mainly caused by human activities. Some have suggested that anthropogenic extinctions may have begun as early as when the first modern humans spread out of Africa between 200,000 and 100,000 years ago; this is supported by rapid megafaunal extinction following recent human colonisation in Australia
Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...
, New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...
and Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Afric ...
. In many cases, it is suggested that even minimal hunting pressure was enough to wipe out large fauna, particularly on geographically isolated islands. Only during the most recent parts of the extinction have plants also suffered large losses.
Extinction rate
The contemporary rate of extinction of species is estimated at 100 to 1,000 times higher than the background extinction rate, the historically typical rate of extinction (in terms of the natural evolution of the planet); also, the current rate of extinction is 10 to 100 times higher than in any of the previous mass extinction
An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. I ...
s in the history of Earth. One scientist estimates the current extinction rate may be 10,000 times the background extinction rate, although most scientists predict a much lower extinction rate than this outlying estimate. Theoretical ecologist Stuart Pimm Stuart Leonard Pimm (born 27 February 1949) is an American-British biologist and theoretical ecologist specializing in scientific research of biodiversity and conservation biology.
Education
Pimm was born in Derbyshire, United Kingdom. He was e ...
stated that the extinction rate for plants is 100 times higher than normal.
Some contend that contemporary extinction has yet to reach the level of the previous five mass extinctions, and that this comparison downplays how severe the first five mass extinctions were. John Briggs argues that there is inadequate data to determine the real rate of extinctions, and shows that estimates of current species extinctions varies enormously, ranging from 1.5 species to 40,000 species going extinct due to human activities each year. Both papers from Barnosky et al. (2011) and Hull et al. (2015) point out that the real rate of extinction during previous mass extinctions is unknown, both as only some organisms leave fossil remains, and as the temporal resolution of the fossil layer is larger than the time frame of the extinction events. However, all these authors agree that there is a modern biodiversity crisis
Biodiversity loss includes the worldwide extinction of different species, as well as the local reduction or loss of species in a certain habitat, resulting in a loss of biological diversity. The latter phenomenon can be temporary or permanent, de ...
with population declines affecting numerous species, and that a future anthropogenic mass extinction event is a big risk. The 2011 study by Barnosky et al. confirms that "current extinction rates are higher than would be expected from the fossil record" and adds that anthropogenic ecological stressors, including climate change, habitat fragmentation, pollution, overfishing, overhunting, invasive species and expanding human biomass
Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bio ...
will intensify and accelerate extinction rates in the future without significant mitigation efforts.
In ''The Future of Life'' (2002), Edward Osborne Wilson of Harvard calculated that, if the current rate of human disruption of the biosphere continues, one-half of Earth's higher lifeforms will be extinct by 2100. A 1998 poll conducted by the American Museum of Natural History
The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 int ...
found that 70% of biologists acknowledge an ongoing anthropogenic extinction event.
In a pair of studies published in 2015, extrapolation from observed extinction of Hawaiian snails led to the conclusion that 7% of all species on Earth may have been lost already. A 2021 study published in the journal ''Frontiers in Forests and Global Change'' found that only around 3% of the planet's terrestrial surface is ecologically and fauna
Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is '' flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. ...
lly intact, meaning areas with healthy populations of native animal species and little to no human footprint.
The 2019 '''', published by the United Nations
The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and security, develop friendly relations among nations, achieve international cooperation, and be a centre for harmoni ...
' Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), posits that roughly one million species of plants and animals face extinction within decades as the result of human actions. Organized human existence is jeopardized by increasingly rapid destruction of the systems that support life on Earth, according to the report, the result of one of the most comprehensive studies of the health of the planet ever conducted. Moreover, the 2021 ''Economics of Biodiversity'' review, published by the UK government, asserts that "biodiversity is declining faster than at any time in human history." According to a 2022 study published in '' Frontiers in Ecology and the Environment'', a survey of more than 3,000 experts says that the extent of the mass extinction might be greater than previously thought, and estimates that roughly 30% of species "have been globally threatened or driven extinct since the year 1500." In a 2022 report, IPBES listed unsustainable fishing, hunting
Hunting is the human activity, human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/hide (skin), hide, ...
and logging
Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars.
Logging is the beginning of a supply cha ...
as being some of the primary drivers of the global extinction crisis.
Attribution
There is widespread consensus among scientists that human activity is accelerating the extinction of many animal species through the destruction of habitats, the consumption of animals as resources, and the elimination of species that humans view as threats or competitors. That humans have become the primary driver of modern extinctions is undeniable, rising extinction trends impacting numerous animal groups including mammals, birds, reptiles, and amphibians have prompted scientists to declare a biodiversity crisis.[ Text and images are available under ]
Creative Commons Attribution 4.0 International License
Scientific debate
Characterisation of recent extinction as a mass extinction has been debated among scientists. Stuart Pimm Stuart Leonard Pimm (born 27 February 1949) is an American-British biologist and theoretical ecologist specializing in scientific research of biodiversity and conservation biology.
Education
Pimm was born in Derbyshire, United Kingdom. He was e ...
, for example, asserts that the sixth mass extinction "is something that hasn't happened yet – we are on the edge of it." Several studies posit that the earth has entered a sixth mass extinction event, including a 2015 paper by Barnosky et al.[ and a November 2017 statement titled " World Scientists’ Warning to Humanity: A Second Notice", led by eight authors and signed by 15,364 scientists from 184 countries which asserted that, among other things, "we have unleashed a mass extinction event, the sixth in roughly 540 million years, wherein many current life forms could be extirpated or at least committed to extinction by the end of this century."] The World Wide Fund for Nature
The World Wide Fund for Nature Inc. (WWF) is an international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the W ...
's 2020 '' Living Planet Report'' says that wildlife
Wildlife refers to undomesticated animal species, but has come to include all organisms that grow or live wild in an area without being introduced by humans. Wildlife was also synonymous to game: those birds and mammals that were hunted ...
populations have declined by 68% since 1970 as a result of overconsumption, population growth
Population growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to ...
and intensive farming, which is further evidence that humans have unleashed a sixth mass extinction event; however, this finding has been disputed by one 2020 study, which posits that this major decline was primarily driven by a few extreme outlier populations, and that when these outliers are removed, the trend shifts to that of a decline between the 1980s and 2000s, but a roughly positive trend after 2000. A 2021 report in ''Frontiers in Conservation Science'' which cites both of the aforementioned studies, says "population sizes of vertebrate species that have been monitored across years have declined by an average of 68% over the last five decades, with certain population clusters in extreme decline, thus presaging the imminent extinction of their species," and asserts "that we are already on the path of a sixth major extinction is now scientifically undeniable." A January 2022 review article published in ''Biological Reviews'' builds upon previous studies documenting biodiversity decline to assert that a sixth mass extinction event caused by anthropogenic activity is currently underway. A December 2022 study published in '' Science Advances'' states that "the planet has entered the sixth mass extinction" and warns that current anthropogenic trends, particularly regarding climate and land-use changes, could result in the loss of more than a tenth of plant and animal species by the end of the century.
According to the UNDP's 2020 Human Development Report, ''The Next Frontier: Human Development and the Anthropocene'':
The 2022 ''Living Planet Report'' found that vertebrate wildlife populations have plummeted by an average of almost 70% since 1970, with agriculture
Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people ...
and fishing
Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from fish stocking, stocked bodies of water such as fish pond, ponds, canals, park wetlands and reservoirs. ...
being the primary drivers of this decline.
Some scientists, including Rodolfo Dirzo
Rodolfo Dirzo is a professor, conservationist, and tropical ecologist. He is a Bing Professor in environmental science at Stanford and a senior fellow at the Stanford Woods Institute for the Environment. His research interests mainly focus on plant ...
and Paul R. Ehrlich, contend that the sixth mass extinction is largely unknown to most people globally, and is also misunderstood by many in the scientific community. They say it is not the disappearance of species, which gets the most attention, that is at the heart of the crisis, but "the existential threat of myriad population extinctions."
Anthropocene
The abundance of species extinctions considered anthropogenic
Anthropogenic ("human" + "generating") is an adjective that may refer to:
* Anthropogeny, the study of the origins of humanity
Counterintuitively, anthropogenic may also refer to things that have been generated by humans, as follows:
* Human i ...
, or due to human activity, has sometimes (especially when referring to hypothesized future events) been collectively called the "Anthropocene extinction". ''Anthropocene'' is a term introduced in 2000. Some now postulate that a new geological epoch has begun, with the most abrupt and widespread extinction of species since the Cretaceous–Paleogene extinction event
The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...
66 million years ago.
The term "anthropocene" is being used more frequently by scientists, and some commentators may refer to the current and projected future extinctions as part of a longer Holocene extinction. The Holocene–Anthropocene boundary is contested, with some commentators asserting significant human influence on climate for much of what is normally regarded as the Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
Epoch
In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured.
The moment of epoch is usually decided ...
. Other commentators place the Holocene–Anthropocene boundary at the industrial revolution
The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...
and also say that " rmal adoption of this term in the near future will largely depend on its utility, particularly to earth scientists working on late Holocene successions."
It has been suggested that human activity has made the period starting from the mid-20th century different enough from the rest of the Holocene to consider it a new geological epoch, known as the Anthropocene, a term which was considered for inclusion in the timeline of Earth's history by the International Commission on Stratigraphy
The International Commission on Stratigraphy (ICS), sometimes referred to unofficially as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigr ...
in 2016. In order to constitute the Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
as an extinction event
An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. I ...
, scientists must determine exactly when anthropogenic greenhouse gas emissions
Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and ...
began to measurably alter natural atmospheric levels on a global scale, and when these alterations caused changes to global climate. Using chemical proxies from Antarctic ice cores, researchers have estimated the fluctuations of carbon dioxide
Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...
(CO2) and methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane ...
(CH4) gases in the Earth's atmosphere during the late Pleistocene
The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch withi ...
and Holocene epochs. Estimates of the fluctuations of these two gases in the atmosphere, using chemical proxies from Antarctic ice cores, generally indicate that the peak of the Anthropocene occurred within the previous two centuries: typically beginning with the Industrial Revolution
The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...
, when the highest greenhouse gas levels were recorded.
Human ecology
A 2015 article in ''Science'' suggested that humans are unique in ecology as an unprecedented "global superpredator", regularly preying on large numbers of fully grown terrestrial and marine apex predators, and with a great deal of influence over food webs and climatic systems worldwide. Although significant debate exists as to how much human predation and indirect effects contributed to prehistoric extinctions, certain population crashes have been directly correlated with human arrival. Human activity has been the main cause of mammalian extinctions since the Late Pleistocene
The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch withi ...
. A 2018 study published in ''PNAS
''Proceedings of the National Academy of Sciences of the United States of America'' (often abbreviated ''PNAS'' or ''PNAS USA'') is a peer-reviewed multidisciplinary scientific journal. It is the official journal of the National Academy of Scie ...
'' found that since the dawn of human civilization, the biomass
Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bio ...
of wild mammals has decreased by 83%. The biomass decrease is 80% for marine mammals, 50% for plants and 15% for fish. Currently, livestock make up 60% of the biomass of all mammals on earth, followed by humans (36%) and wild mammals (4%). As for birds, 70% are domesticated, such as poultry, whereas only 30% are wild.
Historic extinction
Human activity
Activities contributing to extinctions
Extinction of animals, plants, and other organisms caused by human actions may go as far back as the late Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
, over 12,000 years ago. There is a correlation between megafaunal extinction and the arrival of humans. Over the past 125,000 years, the average body size of wildlife has fallen by 14% as human actions eradicated megafauna
In terrestrial zoology, the megafauna (from Greek μέγας ''megas'' "large" and New Latin ''fauna'' "animal life") comprises the large or giant animals of an area, habitat, or geological period, extinct and/or extant. The most common thresho ...
on all continents with the exception of Africa.
Human civilization was founded on and grew from agriculture
Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people ...
. The more land used for farming, the greater the population a civilization could sustain, and subsequent popularization of farming led to habitat conversion.
Habitat destruction by humans, thus replacing the original local ecosystems, is a major driver of extinction. The sustained conversion of biodiversity rich forests and wetlands into poorer fields and pastures (of lesser carrying capacity for wild species), over the last 10,000 years, has considerably reduced the Earth's carrying capacity for wild birds, among other organisms, in both population size and species count.
Other, related human causes of the extinction event include deforestation
Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated ...
, hunting
Hunting is the human activity, human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/hide (skin), hide, ...
, pollution
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, th ...
, the introduction in various regions of non-native species
An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...
, and the widespread transmission of infectious disease
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable di ...
s spread through livestock and crops.[
]
Agriculture and climate change
Recent investigations into the practice of landscape burning during the Neolithic Revolution
The Neolithic Revolution, or the (First) Agricultural Revolution, was the wide-scale transition of many human cultures during the Neolithic period from a lifestyle of hunting and gathering to one of agriculture and settlement, making an inc ...
has a major implication for the current debate about the timing of the Anthropocene and the role that humans may have played in the production of greenhouse gases prior to the Industrial Revolution
The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...
. Studies of early hunter-gatherers raise questions about the current use of population size or density as a proxy
Proxy may refer to:
* Proxy or agent (law), a substitute authorized to act for another entity or a document which authorizes the agent so to act
* Proxy (climate), a measured variable used to infer the value of a variable of interest in climate re ...
for the amount of land clearance and anthropogenic burning that took place in pre-industrial times. Scientists have questioned the correlation between population size and early territorial alterations. Ruddiman and Ellis' research paper in 2009 makes the case that early farmers involved in systems of agriculture used more land per capita than growers later in the Holocene, who intensified their labor to produce more food per unit of area (thus, per laborer); arguing that agricultural involvement in rice production implemented thousands of years ago by relatively small populations have created significant environmental impacts through large-scale means of deforestation.
While a number of human-derived factors are recognized as contributing to rising atmospheric concentrations of CH4 (methane) and CO2 (carbon dioxide), deforestation and territorial clearance practices associated with agricultural development may be contributing most to these concentrations globally. Scientists that are employing a variance of archaeological
Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscap ...
and paleoecological data argue that the processes contributing to substantial human modification of the environment spanned many thousands of years on a global scale and thus, not originating as late as the Industrial Revolution
The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...
. Gaining popularity on his uncommon hypothesis, palaeoclimatologist William Ruddiman
William F. Ruddiman is a palaeoclimatologist and Professor Emeritus at the University of Virginia. Ruddiman earned an undergraduate degree in geology in 1964 at Williams College, and a Ph.D. in marine geology from Columbia University in 1969. Ru ...
in 2003, has argued that in the early Holocene 11,000 years ago, atmospheric carbon dioxide and methane levels fluctuated in a pattern which was different from the Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
epoch before it. He argued that the patterns of the significant decline of CO2 levels during the last ice age of the Pleistocene inversely correlates to the Holocene where there have been dramatic increases of CO2 around 8000 years ago and CH4 levels 3000 years after that. The correlation between the decrease of CO2 in the Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
and the increase of it during the Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...
implies that the causation of this spark of greenhouse gases into the atmosphere was the growth of human agriculture during the Holocene such as the anthropogenic expansion of (human) land use and irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been devel ...
.
Climate change
One of the main theories for the extinction's cause is historic climate change. The climate change theory has suggested that a change in climate near the end of the late Pleistocene stressed the megafauna to the point of extinction. Some scientists favor abrupt climate change as the catalyst for the extinction of the mega-fauna at the end of the Pleistocene, but there are many who believe increased hunting from early modern humans also played a part, with others even suggesting that the two interacted. However, the annual mean temperature of the current interglacial period for the last 10,000 years is no higher than that of previous interglacial periods, yet some of the same megafauna survived similar temperature increases. In the Americas, a controversial explanation for the shift in climate is presented under the Younger Dryas impact hypothesis, which states that the impact of comets cooled global temperatures.
A 2020 study published in '' Science Advances'' found that human population size and/or specific human activities, not climate change, caused rapidly rising global mammal extinction rates during the past 126,000 years. Around 96% of all mammalian extinctions over this time period are attributable to human impacts. According to Tobias Andermann, lead author of the study, "these extinctions did not happen continuously and at constant pace. Instead, bursts of extinctions are detected across different continents at times when humans first reached them. More recently, the magnitude of human driven extinctions has picked up the pace again, this time on a global scale."
Megafaunal extinction
Megafauna play a significant role in the lateral transport of mineral nutrients in an ecosystem, tending to translocate them from areas of high to those of lower abundance. They do so by their movement between the time they consume the nutrient and the time they release it through elimination (or, to a much lesser extent, through decomposition after death). In South America's Amazon Basin
The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries of Boli ...
, it is estimated that such lateral diffusion was reduced over 98% following the megafaunal extinctions that occurred roughly 12,500 years ago. Given that phosphorus
Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ea ...
availability is thought to limit productivity in much of the region, the decrease in its transport from the western part of the basin and from floodplains (both of which derive their supply from the uplift of the Andes
The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...
) to other areas is thought to have significantly impacted the region's ecology, and the effects may not yet have reached their limits. The extinction of the mammoth
A mammoth is any species of the extinct elephantid genus ''Mammuthus'', one of the many genera that make up the order of trunked mammals called proboscideans. The various species of mammoth were commonly equipped with long, curved tusks an ...
s allowed grasslands
A grassland is an area where the vegetation is dominated by grasses ( Poaceae). However, sedge (Cyperaceae) and rush ( Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur nat ...
they had maintained through grazing habits to become birch forests. The new forest and the resulting forest fires may have induced climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
. Such disappearances might be the result of the proliferation of modern humans; some recent studies favor this theory.
Large populations of megaherbivores have the potential to contribute greatly to the atmospheric concentration of methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane ...
, which is an important greenhouse gas
A greenhouse gas (GHG or GhG) is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor (), carbon dioxide (), methane ...
. Modern ruminant herbivores produce methane as a byproduct of foregut fermentation
Foregut fermentation is a form of digestion that occurs in the foregut of some animals. It has evolved independently in several groups of mammals, and also in the hoatzin bird.
Foregut fermentation is employed by ruminants and pseudoruminants, so ...
in digestion, and release it through belching or flatulence. Today, around 20% of annual methane emissions come from livestock methane release. In the Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretace ...
, it has been estimated that sauropod
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', ' lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their ...
s could have emitted 520 million tons of methane to the atmosphere annually, contributing to the warmer climate of the time (up to 10 °C warmer than at present). This large emission follows from the enormous estimated biomass of sauropods, and because methane production of individual herbivores is believed to be almost proportional to their mass.
Recent studies have indicated that the extinction of megafaunal herbivores may have caused a reduction in atmospheric methane. This hypothesis is relatively new. One study examined the methane emissions from the bison
Bison are large bovines in the genus ''Bison'' (Greek: "wild ox" (bison)) within the tribe Bovini. Two extant and numerous extinct species are recognised.
Of the two surviving species, the American bison, ''B. bison'', found only in North A ...
that occupied the Great Plains
The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, a ...
of North America before contact with European settlers. The study estimated that the removal of the bison caused a decrease of as much as 2.2 million tons per year. Another study examined the change in the methane concentration in the atmosphere at the end of the Pleistocene epoch
The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed i ...
after the extinction of megafauna in the Americas. After early humans migrated to the Americas about 13,000 BP, their hunting and other associated ecological impacts led to the extinction of many megafaunal species there. Calculations suggest that this extinction decreased methane production by about 9.6 million tons per year. This suggests that the absence of megafaunal methane emissions may have contributed to the abrupt climatic cooling at the onset of the Younger Dryas
The Younger Dryas (c. 12,900 to 11,700 years BP) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM, c. 27,000 to 20,000 years BP). The Younger Dryas was the last stag ...
. The decrease in atmospheric methane that occurred at that time, as recorded in ice core
An ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier. Since the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper ones, and an ice core contains ...
s, was 2–4 times more rapid than any other decrease in the last half million years, suggesting that an unusual mechanism was at work.
Disease
The hyperdisease hypothesis, proposed by Ross MacPhee in 1997, states that the megafaunal die-off was due to an indirect transmission of diseases by newly arriving humans. According to MacPhee, aboriginals or animals travelling with them, such as domestic dogs or livestock, introduced one or more highly virulent diseases into new environments whose native population had no immunity to them, eventually leading to their extinction. K-selection animals, such as the now-extinct megafauna, are especially vulnerable to diseases, as opposed to r-selection
In ecology, ''r''/''K'' selection theory relates to the selection of combinations of traits in an organism that trade off between quantity and quality of offspring. The focus on either an increased quantity of offspring at the expense of individ ...
animals who have a shorter gestation period
In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once ...
and a higher population size. Humans are thought to be the sole cause as other earlier migrations of animals into North America from Eurasia did not cause extinctions.
There are many problems with this theory, as this disease would have to meet several criteria: it has to be able to sustain itself in an environment with no hosts
A host is a person responsible for guests at an event or for providing hospitality during it.
Host may also refer to:
Places
* Host, Pennsylvania, a village in Berks County
People
*Jim Host (born 1937), American businessman
*Michel Host ...
; it has to have a high infection rate; and be extremely lethal, with a mortality rate
Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular population, scaled to the size of that population, per unit of time. Mortality rate is typically expressed in units of d ...
of 50–75%. Disease has to be very virulent to kill off all the individuals in a species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
, and even such a virulent disease as West Nile fever is unlikely to have caused extinction. However, diseases have been the cause for some extinctions. The introduction of avian malaria and avipoxvirus, for example, have had a negative impact on the endemic birds of Hawaii.
Contemporary extinction
History
Contemporary human overpopulation
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
and continued population growth
Population growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to ...
, along with per-capita consumption growth, prominently in the past two centuries, are regarded as the underlying causes of extinction.
The loss of animal species from ecological communities, defaunation
Defaunation is the global, local or functional extinction of animal populations or species from ecological communities. The growth of the human population, combined with advances in harvesting technologies, has led to more intense and efficient ...
, is primarily driven by human activity. This has resulted in empty forest
Empty forest is a term coined by Kent H. Redford's article "The Empty Forest" (1992), which was published in ''BioScience''. An "empty forest" refers to an ecosystem that is void of large mammals. Empty forests are characterized by an otherwise e ...
s, ecological communities depleted of large vertebrates. This is not to be confused with extinction, as it includes both the disappearance of species and declines in abundance. Defaunation effects were first implied at the Symposium of Plant-Animal Interactions at the University of Campinas, Brazil in 1988 in the context of Neotropical forests. Since then, the term has gained broader usage in conservation biology as a global phenomenon.
Some scholars assert that the emergence of capitalism
Capitalism is an economic system based on the private ownership of the means of production and their operation for profit. Central characteristics of capitalism include capital accumulation, competitive markets, price system, private ...
as the dominant economic system has accelerated ecological exploitation and destruction, and has also exacerbated mass species extinction. CUNY
The City University of New York ( CUNY; , ) is the public university system of New York City. It is the largest urban university system in the United States, comprising 25 campuses: eleven senior colleges, seven community colleges and seven prof ...
professor David Harvey, for example, posits that the neoliberal
Neoliberalism (also neo-liberalism) is a term used to signify the late 20th century political reappearance of 19th-century ideas associated with free-market capitalism after it fell into decline following the Second World War. A prominent f ...
era "happens to be the era of the fastest mass extinction of species in the Earth's recent history". Major lobbying organizations representing corporations in the agriculture, fisheries, forestry and paper, mining, and oil and gas industries, including the United States Chamber of Commerce, have been pushing back against legislation that could address the extinction crisis. A 2022 report by the climate think tank InfluenceMap stated that "although industry associations, especially in the US, appear reluctant to discuss the biodiversity crisis, they are clearly engaged on a wide range of policies with significant impacts on biodiversity loss."
Big cat populations have severely declined over the last half-century and could face extinction in the following decades. According to 2011 IUCN
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
estimates: lions
The lion (''Panthera leo'') is a large cat of the genus '' Panthera'' native to Africa and India. It has a muscular, broad-chested body; short, rounded head; round ears; and a hairy tuft at the end of its tail. It is sexually dimorphic; ad ...
are down to 25,000, from 450,000; leopards are down to 50,000, from 750,000; cheetahs are down to 12,000, from 45,000; tigers are down to 3,000 in the wild, from 50,000. A December 2016 study by the Zoological Society of London, Panthera Corporation and Wildlife Conservation Society showed that cheetahs are far closer to extinction than previously thought, with only 7,100 remaining in the wild, existing within only 9% of their historic range. Human pressures are to blame for the cheetah population crash, including prey loss due to overhunting by people, retaliatory killing from farmers, habitat loss and the illegal wildlife trade.
The term pollinator decline
Pollinator decline is the reduction in abundance of insect and other animal pollinators in many ecosystems worldwide that began being recorded at the end of the 20th century. Multiple lines of evidence exist for the reduction of wild pollinato ...
refers to the reduction in abundance of insect and other animal pollinators in many ecosystems worldwide beginning at the end of the twentieth century, and continuing into the present day. Pollinators, which are necessary for 75% of food crops, are declining globally in both abundance and diversity. A 2017 study led by Radboud University's Hans de Kroon indicated that the biomass of insect life in Germany had declined by three-quarters in the previous 25 years. Participating researcher Dave Goulson of Sussex University
, mottoeng = Be Still and Know
, established =
, type = Public research university
, endowment = £14.4 million (2020)
, budget = £319.6 million (2019–20)
, chancellor = Sanjeev Bhaskar
, vice_chancellor = Sasha Roseneil
, ...
stated that their study suggested that humans are making large parts of the planet uninhabitable for wildlife. Goulson characterized the situation as an approaching "ecological Armageddon", adding that "if we lose the insects then everything is going to collapse." A 2019 study found that over 40% of insect species are threatened with extinction. The most significant drivers in the decline of insect populations are associated with intensive farming practices, along with pesticide use and climate change. The world's insect population decreases by around 1 to 2 per cent per year.
Various species are predicted to become extinct in the near future, among them the rhinoceros
A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct specie ...
, nonhuman primates
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter including ...
, pangolins, and giraffes. Hunting
Hunting is the human activity, human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/hide (skin), hide, ...
alone threatens bird and mammalian populations around the world. The direct killing of megafauna
In terrestrial zoology, the megafauna (from Greek μέγας ''megas'' "large" and New Latin ''fauna'' "animal life") comprises the large or giant animals of an area, habitat, or geological period, extinct and/or extant. The most common thresho ...
for meat and body parts is the primary driver of their destruction, with 70% of the 362 megafauna species in decline as of 2019. Mammals in particular have suffered such severe losses as the result of human activity that it could take several million years for them to recover. Contemporary assessments have discovered that roughly 41% of amphibians, 25% of mammals, 21% of reptiles and 14% of birds are threatened with extinction, which could disrupt ecosystems on a global scale and eliminate billions of years of phylogenetic diversity Phylogenetic diversity is a measure of biodiversity which incorporates phylogenetic difference between species. It is defined and calculated as "the sum of the lengths of all those branches that are members of the corresponding minimum spanning pa ...
. 189 countries, which are signatory to the Convention on Biological Diversity (Rio Accord), have committed to preparing a Biodiversity Action Plan, a first step at identifying specific endangered species
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
and habitats, country by country.
Recent extinction
Recent extinctions are more directly attributable to human influences, whereas prehistoric extinctions can be attributed to other factors, such as global climate change.[ The ]International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...
(IUCN) characterises 'recent' extinction as those that have occurred past the cut-off point of 1500, and at least 875 plant and animal species have gone extinct since that time and 2009. Some species, such as the Père David's deer
The Père David's deer (''Elaphurus davidianus''), also known as the ''milu'' () or elaphure, is a species of deer native to the subtropical river valleys of China. It grazes mainly on grass and aquatic plants. It is the only extant member of ...
and the Hawaiian crow, are extinct in the wild, and survive solely in captive populations. Other populations are only locally extinct (extirpated), still existent elsewhere, but reduced in distribution, as with the extinction of gray whale
The gray whale (''Eschrichtius robustus''), also known as the grey whale,Britannica Micro.: v. IV, p. 693. gray back whale, Pacific gray whale, Korean gray whale, or California gray whale, is a baleen whale that migrates between feeding and bre ...
s in the Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
, and of the leatherback sea turtle
The leatherback sea turtle (''Dermochelys coriacea''), sometimes called the lute turtle or leathery turtle or simply the luth, is the largest of all living turtles and the heaviest non-crocodilian reptile, reaching lengths of up to and weight ...
in Malaysia.
Humans are rapidly driving the largest vertebrate animals towards extinction, and in the process interrupting a 66-million-year-old feature of ecosystems, the relationship between diet and body mass, which researchers suggest could have unpredictable consequences. A 2019 study published in ''Nature Communications
''Nature Communications'' is a peer-reviewed, open access, scientific journal published by Nature Portfolio since 2010. It is a multidisciplinary journal and it covers the natural sciences, including physics, chemistry, earth sciences, medic ...
'' found that rapid biodiversity loss is impacting larger mammals and birds to a much greater extent than smaller ones, with the body mass of such animals expected to shrink by 25% over the next century. Another 2019 study published in '' Biology Letters'' found that extinction rates are perhaps much higher than previously estimated, in particular for bird species.
The 2019 '''' lists the primary causes of contemporary extinctions in descending order: (1) changes in land and sea use (primarily agriculture and overfishing respectively); (2) direct exploitation of organisms such as hunting; (3) anthropogenic climate change; (4) pollution and (5) invasive alien species spread by human trade. This report, along with the 2020 '' Living Planet Report'' by the WWF, both project that climate change will be the leading cause in the next several decades.
A June 2020 study published in ''PNAS
''Proceedings of the National Academy of Sciences of the United States of America'' (often abbreviated ''PNAS'' or ''PNAS USA'') is a peer-reviewed multidisciplinary scientific journal. It is the official journal of the National Academy of Scie ...
'' posits 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." The study found that more than 500 vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with ...
species are poised to be lost in the next two decades.
Habitat destruction
Humans both create and destroy crop cultivar and domesticated animal
This page gives a list of domesticated animals, also including a list of domestication of animals, animals which are or may be currently undergoing the process of domestication and animals that have an extensive relationship with humans beyond simp ...
varieties. Advances in transportation and industrial farming has led to monoculture and the extinction of many cultivars. The use of certain plants and animals for food has also resulted in their extinction, including silphium and the passenger pigeon. It was estimated in 2012 that 13 percent of Earth's ice-free land surface is used as row-crop agricultural sites, 26 percent used as pastures, and 4 percent urban-industrial areas.
In March 2019, '' Nature Climate Change'' published a study by ecologists from Yale University
Yale University is a private research university in New Haven, Connecticut. Established in 1701 as the Collegiate School, it is the third-oldest institution of higher education in the United States and among the most prestigious in the w ...
, who found that over the next half century, human land use will reduce the habitats of 1,700 species by up to 50%, pushing them closer to extinction. That same month '' PLOS Biology'' published a similar study drawing on work at the University of Queensland
, mottoeng = By means of knowledge and hard work
, established =
, endowment = A$224.3 million
, budget = A$2.1 billion
, type = Public research university
, chancellor = Peter Varghese
, vice_chancellor = Deborah Terry
, city = B ...
, which found that "more than 1,200 species globally face threats to their survival in more than 90% of their habitat and will almost certainly face extinction without conservation intervention".
Since 1970, the populations of migratory freshwater fish have declined by 76%, according to research published by the Zoological Society of London
The Zoological Society of London (ZSL) is a charity devoted to the worldwide conservation of animals and their habitats. It was founded in 1826. Since 1828, it has maintained the London Zoo, and since 1931 Whipsnade Park.
History
On 29 ...
in July 2020. Overall, around one in three freshwater fish species are threatened with extinction due to human-driven habitat degradation and overfishing.
Some scientists and academics assert that industrial agriculture
Industrial agriculture is a form of modern farming that refers to the industrialized production of crops and animals and animal products like eggs or milk. The methods of industrial agriculture include innovation in agricultural machinery and fa ...
and the growing demand for meat is contributing to significant global biodiversity loss as this is a significant driver of deforestation
Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated ...
and habitat destruction; species-rich habitats, such as the Amazon region and Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Gui ...
being converted to agriculture. A 2017 study by the World Wildlife Fund
The World Wide Fund for Nature Inc. (WWF) is an international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the W ...
(WWF) found that 60% of biodiversity loss can be attributed to the vast scale of feed crop cultivation required to rear tens of billions of farm animals. Moreover, a 2006 report by the Food and Agriculture Organization
The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...
(FAO) of the United Nations
The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and security, develop friendly relations among nations, achieve international cooperation, and be a centre for harmoni ...
, ''Livestock's Long Shadow
''Livestock's Long Shadow: Environmental Issues and Options'' is a United Nations report, released by the Food and Agriculture Organization (FAO) of the United Nations on 29 November 2006, that "aims to assess the full impact of the livestock s ...
'', also found that the livestock sector is a "leading player" in biodiversity loss. More recently, in 2019, the IPBES
The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) is an intergovernmental organization established to improve the interface between science and policy on issues of biodiversity and ecosystem services. It ...
'''' attributed much of this ecological destruction to agriculture and fishing, with the meat and dairy industries having a very significant impact. Since the 1970s food production has soared in order to feed a growing human population and bolster economic growth
Economic growth can be defined as the increase or improvement in the inflation-adjusted market value of the goods and services produced by an economy in a financial year. Statisticians conventionally measure such growth as the percent rate o ...
, but at a huge price to the environment and other species. The report says some 25% of the earth's ice-free land is used for cattle grazing. A 2020 study published in ''Nature Communications
''Nature Communications'' is a peer-reviewed, open access, scientific journal published by Nature Portfolio since 2010. It is a multidisciplinary journal and it covers the natural sciences, including physics, chemistry, earth sciences, medic ...
'' warned that human impacts from housing, industrial agriculture and in particular meat consumption are wiping out a combined 50 billion years of earth's evolutionary history (defined as phylogenetic diversity) and driving to extinction some of the "most unique animals on the planet," among them the Aye-aye
The aye-aye (''Daubentonia madagascariensis'') is a long-fingered lemur, a strepsirrhine primate native to Madagascar with rodent-like teeth that perpetually grow and a special thin middle finger.
It is the world's largest nocturnal primate. ...
lemur, the Chinese crocodile lizard and the pangolin
Pangolins, sometimes known as scaly anteaters, are mammals of the order Pholidota (, from Ancient Greek ϕολιδωτός – "clad in scales"). The one extant family, the Manidae, has three genera: '' Manis'', ''Phataginus'', and '' Smuts ...
. Said lead author Rikki Gumbs:
Climate change
Climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
is expected to be a major driver of extinctions from the 21st century. Rising levels of carbon dioxide are resulting in influx of this gas into the ocean, increasing its acidity. Marine organisms which possess calcium carbonate shells or exoskeleton
An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton ( endoskeleton) in for example, a human. In usage, some of the ...
s experience physiological pressure as the carbonate reacts with acid. For example, this is already resulting in coral bleaching
Coral bleaching is the process when corals become white due to various stressors, such as changes in temperature, light, or nutrients. Bleaching occurs when coral polyps expel the zooxanthellae ( dinoflagellates that are commonly referred to as ...
on various coral reef
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held together by calcium carbonate. Most coral reefs are built from stony corals, wh ...
s worldwide, which provide valuable habitat and maintain a high biodiversity. Marine gastropod
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...
s, bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of marine and freshwater Mollusca, molluscs that have laterally compressed bodies enclosed by a shell consisting of two hing ...
s and other invertebrates are also affected, as are the organisms that feed on them. Some studies have suggested that it is not climate change that is driving the current extinction crisis, but the demands of contemporary human civilization on nature.
Overexploitation
Overhunting can reduce the local population of game animals by more than half, as well as reducing population density, and may lead to extinction for some species. Populations located nearer to villages are significantly more at risk of depletion. Several conservationist organizations, among them IFAW
Ifo is a town in south-western Nigeria near Lagos.
Transport
It is served by a junction station on the national railway network.
See also
* Railway stations in Nigeria
Railway stations in Nigeria include:
Maps
UN MapUNHCR A ...
and HSUS
The Humane Society of the United States (HSUS) is an American nonprofit organization that focuses on animal welfare and opposes animal-related cruelties of national scope. It uses strategies that are beyond the abilities of local organizations. ...
, assert that trophy hunters, particularly from the United States, are playing a significant role in the decline of giraffes, which they refer to as a "silent extinction".
The surge in the mass killings by poachers involved in the illegal ivory trade along with habitat loss is threatening African elephant populations. In 1979, their populations stood at 1.7 million; at present there are fewer than 400,000 remaining. Prior to European colonization, scientists believe Africa was home to roughly 20 million elephants. According to the Great Elephant Census, 30% of African elephants (or 144,000 individuals) disappeared over a seven-year period, 2007 to 2014. African elephants could become extinct by 2035 if poaching rates continue.
Fishing has had a devastating effect on marine organism populations for several centuries even before the explosion of destructive and highly effective fishing practices like trawling
Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different spec ...
. Humans are unique among predators in that they regularly prey on other adult apex predators, particularly in marine environments; bluefin tuna, blue whales
The blue whale (''Balaenoptera musculus'') is a marine mammal and a baleen whale. Reaching a maximum confirmed length of and weighing up to , it is the largest animal known to have ever existed. The blue whale's long and slender body can b ...
, North Atlantic right whales and over fifty species of shark
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachi ...
s and ray
Ray may refer to:
Fish
* Ray (fish), any cartilaginous fish of the superorder Batoidea
* Ray (fish fin anatomy), a bony or horny spine on a fin
Science and mathematics
* Ray (geometry), half of a line proceeding from an initial point
* Ray (gr ...
s are vulnerable to predation pressure from human fishing, in particular commercial fishing. A 2016 study published in ''Science'' concludes that humans tend to hunt larger species, and this could disrupt ocean ecosystems for millions of years. A 2020 study published in '' Science Advances'' found that around 18% of marine megafauna, including iconic species such as the Great white shark
The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large mackerel shark which can be found in the coastal surface waters of all the major oceans. It is nota ...
, are at risk of extinction from human pressures over the next century. In a worst-case scenario, 40% could go extinct over the same time period. According to a 2021 study published in ''Nature'', 71% of oceanic shark and ray populations have been destroyed by overfishing
Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in t ...
(the primary driver of ocean defaunation
Defaunation is the global, local or functional extinction of animal populations or species from ecological communities. The growth of the human population, combined with advances in harvesting technologies, has led to more intense and efficient ...
) from 1970 to 2018, and are nearing the "point of no return" as 24 of the 31 species are now threatened with extinction, with several being classified as critically endangered.
Disease
The decline of amphibian populations has also been identified as an indicator of environmental degradation. As well as habitat loss, introduced predators and pollution, Chytridiomycosis, a fungal infection accidentally spread by human travel, globalization and the wildlife trade, has caused severe population drops of over 500 amphibian species, and perhaps 90 extinctions, including (among many others) the extinction of the golden toad in Costa Rica, the Gastric-brooding frog
The gastric-brooding frogs or platypus frogs (''Rheobatrachus'') is a genus of extinct ground-dwelling frogs native to Queensland in eastern Australia. The genus consisted of only two species, both of which became extinct in the mid-1980s. The ...
in Australia, the Rabb's fringe-limbed treefrog and the extinction of the Panamanian golden frog in the wild. Chytrid fungus has spread across Australia, New Zealand, Central America and Africa, including countries with high amphibian diversity such as cloud forests in Honduras
Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Oce ...
and Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Afric ...
. '' Batrachochytrium salamandrivorans'' is a similar infection currently threatening salamander
Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...
s. Amphibians are now the most endangered vertebrate group, having existed for more than 300 million years through three other mass extinction
An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. I ...
s.
Millions of bats in the US have been dying off since 2012 due to a fungal infection known as white-nose syndrome
White-nose syndrome (WNS) is a fungal disease in North American bats which has resulted in the dramatic decrease of the bat population in the United States and Canada, reportedly killing millions as of 2018. The condition is named for a distincti ...
that spread from European bats, who appear to be immune. Population drops have been as great as 90% within five years, and extinction of at least one bat species is predicted. There is currently no form of treatment, and such declines have been described as "unprecedented" in bat evolutionary history by Alan Hicks of the New York State Department of Environmental Conservation.
Between 2007 and 2013, over ten million beehives were abandoned due to colony collapse disorder, which causes worker bees to abandon the queen
Queen or QUEEN may refer to:
Monarchy
* Queen regnant, a female monarch of a Kingdom
** List of queens regnant
* Queen consort, the wife of a reigning king
* Queen dowager, the widow of a king
* Queen mother, a queen dowager who is the mother ...
. Though no single cause has gained widespread acceptance by the scientific community, proposals include infections with '' Varroa'' and ''Acarapis'' mite
Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear e ...
s; malnutrition
Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is "a deficiency, excess, or imbalance of energy, protein and other nutrients" which adversely affects the body's tissues ...
; various pathogen
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a g ...
s; genetic factors; immunodeficiencies
Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that a ...
; loss of habitat; changing beekeeping
Beekeeping (or apiculture) is the maintenance of bee colonies, commonly in man-made beehives. Honey bees in the genus ''Apis (insect), Apis'' are the most-commonly-kept species but other honey-producing bees such as ''Melipona'' stingless bees ar ...
practices; or a combination of factors.
By region
Megafauna
In terrestrial zoology, the megafauna (from Greek μέγας ''megas'' "large" and New Latin ''fauna'' "animal life") comprises the large or giant animals of an area, habitat, or geological period, extinct and/or extant. The most common thresho ...
were once found on every continent of the world, but are now almost exclusively found on the continent of Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
. In some regions, megafauna experienced population crashes and trophic cascades shortly after the earliest human settlers. Worldwide, 178 species of the world's largest mammals died out between 52,000 and 9,000 BC; it has been suggested that a higher proportion of African megafauna survived because they evolved alongside humans. The timing of South American megafaunal extinction appears to precede human arrival, although the possibility that human activity at the time impacted the global climate enough to cause such an extinction has been suggested.
Afroeurasia
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
experienced the smallest decline in megafauna compared to the other continents. This is presumably due to the idea that Afroeurasian megafauna evolved alongside humans, and thus developed a healthy fear of them, unlike the comparatively tame animals of other continents. Unlike other continents, the megafauna of Eurasia went extinct over a relatively long period of time, possibly due to climate fluctuations fragmenting and decreasing populations, leaving them vulnerable to over-exploitation, as with the steppe bison
The steppe bisonSeveral literatures address the species as ''primeval bison''. or steppe wisent (''Bison'' ''priscus'')
– Y ...
(''Bison priscus''). The warming of the arctic region caused the rapid decline of grasslands, which had a negative effect on the grazing megafauna of Eurasia. Most of what once was mammoth steppe
During the Last Glacial Maximum, the mammoth steppe, also known as steppe-tundra, was the Earth's most extensive biome. It spanned from Spain eastward across Eurasia to Canada and from the arctic islands southward to China. The mammoth step ...
was converted to mire, rendering the environment incapable of supporting them, notably the woolly mammoth.
Americas
There has been a debate as to the extent to which the disappearance of megafauna
In terrestrial zoology, the megafauna (from Greek μέγας ''megas'' "large" and New Latin ''fauna'' "animal life") comprises the large or giant animals of an area, habitat, or geological period, extinct and/or extant. The most common thresho ...
at the end of the last glacial period can be attributed to human activities by hunting, or even by slaughter of prey populations. Discoveries at Monte Verde in South America and at Meadowcroft Rock Shelter in Pennsylvania have caused a controversy[The Early Settlement of North America. The Clovis Era. Gary Haynes 2002 . 18–19.] regarding the Clovis culture. There likely would have been human settlements prior to the Clovis culture, and the history of humans in the Americas may extend back many thousands of years before the Clovis culture. The amount of correlation between human arrival and megafauna extinction is still being debated: for example, in Wrangel Island in Siberia the extinction of dwarf woolly mammoths (approximately 2000 BCE) did not coincide with the arrival of humans, nor did megafaunal mass extinction on the South American continent, although it has been suggested climate changes induced by anthropogenic effects elsewhere in the world may have contributed.
Comparisons are sometimes made between recent extinctions (approximately since the industrial revolution
The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...
) and the Pleistocene extinction near the end of the last glacial period. The latter is exemplified by the extinction of large herbivores such as the woolly mammoth and the carnivores that preyed on them. Humans of this era actively hunted the mammoth
A mammoth is any species of the extinct elephantid genus ''Mammuthus'', one of the many genera that make up the order of trunked mammals called proboscideans. The various species of mammoth were commonly equipped with long, curved tusks an ...
and the mastodon
A mastodon ( 'breast' + 'tooth') is any proboscidean belonging to the extinct genus ''Mammut'' (family Mammutidae). Mastodons inhabited North and Central America during the late Miocene or late Pliocene up to their extinction at the end of the ...
, but it is not known if this hunting was the cause of the subsequent massive ecological changes, widespread extinctions and climate changes.
The ecosystems encountered by the first Americans had not been exposed to human interaction, and may have been far less resilient to human made changes than the ecosystems encountered by industrial era humans. Therefore, the actions of the Clovis people, despite seeming insignificant by today's standards could indeed have had a profound effect on the ecosystems and wild life which was entirely unused to human influence.
Australia
Australia
Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...
was once home to a large assemblage of megafauna, with many parallels to those found on the African continent today. Australia's fauna is characterised by primarily marsupial
Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in ...
mammals, and many reptiles and birds, all existing as giant forms until recently. Humans" \n\n\n\n\nThe robots exclusion standard, also known as the robots exclusion protocol or simply robots.txt, is a standard used by websites to indicate to visiting web crawlers and other web robots which portions of the site they are allowed to visi ...
arrived on the continent very early, about 50,000 years ago. The extent human arrival contributed is controversial; climatic drying of Australia 40,000–60,000 years ago was an unlikely cause, as it was less severe in speed or magnitude than previous regional climate change which failed to kill off megafauna. Extinctions in Australia continued from original settlement until today in both plants and animals, whilst many more animals and plants have declined or are endangered.
Due to the older timeframe and the soil chemistry on the continent, very little subfossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
preservation evidence exists relative to elsewhere. However, continent-wide extinction of all genera weighing over 100 kilograms, and six of seven genera weighing between 45 and 100 kilograms occurred around 46,400 years ago (4,000 years after human arrival) and the fact that megafauna survived until a later date on the island of Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
following the establishment of a land bridge suggest direct hunting or anthropogenic ecosystem disruption such as fire-stick farming as likely causes. The first evidence of direct human predation leading to extinction in Australia was published in 2016.
A 2021 study found that the rate of extinction of Australia's megafauna is rather unusual, with some generalistic species having gone extinct earlier while highly specialised ones having become extinct later or even still surviving today. A mosaic cause of extinction with different anthropogenic and environmental pressures has been proposed.
Caribbean
Human arrival in the Caribbean
The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean ...
around 6,000 years ago is correlated with the extinction of many species. These include many different genera of ground and arboreal sloths across all islands. These sloths were generally smaller than those found on the South American continent. '' Megalocnus'' were the largest genus at up to , ''Acratocnus
''Acratocnus'' is an extinct genus of ground sloths that were found on Cuba, Hispaniola (today the Dominican Republic and Haiti), and Puerto Rico.
Classification
Like all of the Antillean sloths, ''Acratocnus'' was formerly thought on the ba ...
'' were medium-sized relatives of modern two-toed sloths endemic to Cuba
Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribb ...
, ''Imagocnus
''Imagocnus'' is an extinct genus of ground sloth from the Early Miocene (Burdigalian) Lagunitas Formation of Cuba.
Description
This sloth resided in the Antilles and showed a range of body size, from ''Parocnus
''Parocnus'' is an ext ...
'' also of Cuba, ''Neocnus
''Neocnus'' is an extinct genus of ground sloth, whose species ranged across Cuba and Hispaniola (today split between Haiti and the Dominican Republic). ''Neocnus'' would have resembled a typical ground sloth, though much smaller, with a longer ...
'' and many others.
Macaronesia
The arrival of the first human settlers in the Azores
)
, motto =( en, "Rather die free than subjected in peace")
, anthem= ( en, "Anthem of the Azores")
, image_map=Locator_map_of_Azores_in_EU.svg
, map_alt=Location of the Azores within the European Union
, map_caption=Location of the Azores wi ...
saw the introduction of invasive plants and livestock to the archipelago, resulting in the extinction of at least two plant species on Pico Island. Lacustrine ecosystems were ravaged by human colonisation, as evidenced by hydrogen isotopes from C30 fatty acids recording hypoxic bottom waters caused by eutrophication in Lake Funda on Flores Island beginning between 1500 and 1600 AD.
In the Canary Islands
The Canary Islands (; es, :es:Canarias, Canarias, ), also known informally as the Canaries, are a Spanish Autonomous communities of Spain, autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to ...
, native thermophilous woodlands were decimated and two tree taxa were driven extinct following the arrival of its first humans, primarily as a result of increased fire clearance and soil erosion and the introduction of invasive pigs, goats, and rats. Invasive species introductions accelerated during the Age of Discovery
The Age of Discovery (or the Age of Exploration), also known as the early modern period, was a period largely overlapping with the Age of Sail, approximately from the 15th century to the 17th century in European history, during which seafa ...
when Europeans first settled the Macaronesian archipelago. The archipelago's laurel forests, though still negatively impacted, fared better due to being less suitable for human economic use.
Cabo Verde, like the Canary Islands, witnessed precipitous deforestation upon the arrival of European settlers and various invasive species brought by them in the archipelago, with the archipelago's thermophilous woodlands suffering the greatest destruction. Introduced species, overgrazing, increased fire incidence, and soil degradation have been attributed as the chief causes of Cabo Verde's ecological devastation.
Pacific
Archaeological and paleontological digs on 70 different Pacific islands
Collectively called the Pacific Islands, the islands in the Pacific Ocean are further categorized into three major island groups: Melanesia, Micronesia, and Polynesia. Depending on the context, the term ''Pacific Islands'' may refer to one of se ...
suggested that numerous species became extinct as people moved across the Pacific, starting 30,000 years ago in the Bismarck Archipelago
The Bismarck Archipelago (, ) is a group of islands off the northeastern coast of New Guinea in the western Pacific Ocean and is part of the Islands Region of Papua New Guinea. Its area is about 50,000 square km.
History
The first inhabitants o ...
and Solomon Islands
Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its capit ...
. It is currently estimated that among the bird species of the Pacific, some 2000 species have gone extinct since the arrival of humans, representing a 20% drop in the biodiversity of birds worldwide.
The first human settlers of the Hawaiian islands
The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost ...
are thought to have arrived between 300 and 800 CE, with European arrival in the 16th century. Hawaii is notable for its endemism
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...
of plants, birds
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
, insects, mollusks and fish
Fish are Aquatic animal, aquatic, craniate, gill-bearing animals that lack Limb (anatomy), limbs with Digit (anatomy), digits. Included in this definition are the living hagfish, lampreys, and Chondrichthyes, cartilaginous and bony fish as we ...
; 30% of its organisms are endemic. Many of its species are endangered or have gone extinct, primarily due to accidentally introduced species and livestock grazing. Over 40% of its bird species have gone extinct, and it is the location of 75% of extinctions in the United States. Extinction has increased in Hawaii over the last 200 years and is relatively well documented, with extinctions among native snails used as estimates for global extinction rates.
Madagascar
Within 500 years of the arrival of humans" \n\n\n\n\nThe robots exclusion standard, also known as the robots exclusion protocol or simply robots.txt, is a standard used by websites to indicate to visiting web crawlers and other web robots which portions of the site they are allowed to visi ...
between 2,500 and 2,000 years ago, nearly all of Madagascar's distinct, endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...
and geographically isolated megafauna became extinct. The largest animals, of more than , were extinct very shortly after the first human arrival, with large and medium-sized species dying out after prolonged hunting pressure from an expanding human population moving into more remote regions of the island around 1000 years ago. The eight or more species of elephant birds, giant flightless ratite
A ratite () is any of a diverse group of flightless, large, long-necked, and long-legged birds of the infraclass Palaeognathae. Kiwi, the exception, are much smaller and shorter-legged and are the only nocturnal extant ratites.
The systematics ...
s in the genera '' Aepyornis'', '' Vorombe'', and '' Mullerornis'', are extinct from over-hunting, as well as 17 species of lemur, known as giant, subfossil lemurs. Some of these lemurs typically weighed over , and their fossils have provided evidence of human butchery on many species. Smaller fauna experienced initial increases due to decreased competition, and then subsequent declines over the last 500 years. All fauna weighing over died out. The primary reasons for the decline of Madagascar's biota, which at the time was already stressed by natural aridification, were human hunting, herding, farming, and forest clearing, all of which persist and threaten Madagascar's remaining taxa today. The natural ecosystems of Madagascar as a whole were further impacted by the much greater incidence of fire as a result of anthropogenic fire production; evidence from Lake Amparihibe on the island of Nosy Be indicates a shift in local vegetation from intact rainforest to a fire-disturbed patchwork of grassland and woodland between 1300 and 1000 BP.
New Zealand
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...
is characterised by its geographic isolation
Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...
and island biogeography, and had been isolated from mainland Australia for 80 million years. It was the last large land mass to be colonised by humans. The arrival of Polynesia
Polynesia () "many" and νῆσος () "island"), to, Polinisia; mi, Porinihia; haw, Polenekia; fj, Polinisia; sm, Polenisia; rar, Porinetia; ty, Pōrīnetia; tvl, Polenisia; tkl, Polenihia (, ) is a subregion of Oceania, made up of ...
n settlers circa 12th century resulted in the extinction of all of the islands' megafaunal birds within several hundred years. The moa, large flightless ratite
A ratite () is any of a diverse group of flightless, large, long-necked, and long-legged birds of the infraclass Palaeognathae. Kiwi, the exception, are much smaller and shorter-legged and are the only nocturnal extant ratites.
The systematics ...
s, became extinct within 200 years of the arrival of human settlers. The Polynesians also introduced the Polynesian rat
The Polynesian rat, Pacific rat or little rat (''Rattus exulans''), known to the Māori as ''kiore'', is the third most widespread species of rat in the world behind the brown rat and black rat. The Polynesian rat originated in Southeast Asia, a ...
. This may have put some pressure on other birds but at the time of early European contact (18th century) and colonisation (19th century) the bird life was prolific. With them, the Europeans brought various invasive species including ship rats, possums, cats and mustelids which devastated native bird life, some of which had adapted flightlessness and ground nesting habits, and had no defensive behavior as a result of having no native mammalian predators. The kakapo, the world's biggest parrot, which is flightless, now only exists in managed breeding sanctuaries. New Zealand's national emblem, the kiwi, is on the endangered bird list.
Mitigation
Stabilizing human populations
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, an ...
, reining in capitalism
Capitalism is an economic system based on the private ownership of the means of production and their operation for profit. Central characteristics of capitalism include capital accumulation, competitive markets, price system, private ...
and decreasing economic demands, transitioning to plant-based diets, and increasing the number and size of terrestrial and marine protected areas are the keys to avoiding or limiting biodiversity loss and a possible sixth mass extinction. Rodolfo Dirzo
Rodolfo Dirzo is a professor, conservationist, and tropical ecologist. He is a Bing Professor in environmental science at Stanford and a senior fellow at the Stanford Woods Institute for the Environment. His research interests mainly focus on plant ...
and Paul R. Ehrlich suggest that "the one fundamental, necessary, 'simple' cure, ... is reducing the scale of the human enterprise."
A 2018 article in ''Science
Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe.
Science may be as old as the human species, and some of the earliest archeological evidence ...
'' advocated for the global community to designate 30 percent of the planet by 2030, and 50 percent by 2050, as protected area
Protected areas or conservation areas are locations which receive protection because of their recognized natural, ecological or cultural values. There are several kinds of protected areas, which vary by level of protection depending on the ena ...
s in order to mitigate the contemporary extinction crisis. It highlighted that the human population is projected to grow to 10 billion by the middle of the century, and consumption of food and water resources is projected to double by this time.
In November 2018, the UN's biodiversity chief Cristiana Pașca Palmer urged people around the world to put pressure on governments to implement significant protections for wildlife by 2020. She called biodiversity loss a "silent killer" as dangerous as global warming
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
, but said it had received little attention by comparison. "It’s different from climate change, where people feel the impact in everyday life. With biodiversity, it is not so clear but by the time you feel what is happening, it may be too late." In January 2020, the UN Convention on Biological Diversity drafted a Paris-style plan to stop biodiversity and ecosystem collapse by setting the deadline of 2030 to protect 30% of the earth's land and oceans and to reduce pollution
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, th ...
by 50%, with the goal of allowing for the restoration of ecosystems by 2050. The world failed to meet the Aichi Biodiversity targets for 2020 set by the convention during a summit in Japan in 2010. Of the 20 biodiversity targets proposed, only six were "partially achieved" by the deadline. It was called a global failure by Inger Andersen, head of the United Nations Environment Programme
The United Nations Environment Programme (UNEP) is responsible for coordinating responses to environmental issues within the United Nations system. It was established by Maurice Strong, its first director, after the United Nations Conference on ...
:
Some scientists have proposed keeping extinctions below 20 per year for the next century as a global target to reduce species loss, which is the biodiversity equivalent of the 2 °C climate target, although it is still much higher than the normal background rate of two per year prior to anthropogenic impacts on the natural world.
An October 2020 report on the "era of pandemics" from IPBES
The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) is an intergovernmental organization established to improve the interface between science and policy on issues of biodiversity and ecosystem services. It ...
found that many of the same human activities that contribute to biodiversity loss and climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...
, including deforestation
Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated ...
and the wildlife trade
Wildlife trade refers to the of products that are derived from non-domesticated animals or plants usually extracted from their natural environment or raised under controlled conditions. It can involve the trade of living or dead individuals, t ...
, have also increased the risk of future pandemics. The report offers several policy options to reduce such risk, such as taxing meat production and consumption, cracking down on the illegal wildlife trade, removing high disease-risk species from the legal wildlife trade, and eliminating subsidies to businesses which are harmful to the environment. According to marine zoologist John Spicer, "the COVID-19 crisis
The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identified ...
is not just another crisis alongside the biodiversity crisis and the climate change crisis. Make no mistake, this is one big crisis – the greatest that humans have ever faced."
According to a 2021 paper published in ''Frontiers in Conservation Science
Frontiers Media SA is a publisher of peer-reviewed, open access, scientific journals currently active in science, technology, and medicine. It was founded in 2007 by Kamila and Henry Markram, and has since expanded to other academic fields. Fro ...
'', humanity almost certainly faces a "ghastly future" of mass extinction, biodiversity collapse, climate change and their impacts unless major efforts to change human industry and activity are rapidly undertaken.
A 2022 report published in ''Science'' warned that 44% of earth's terrestrial surface, or 24.7 million square miles, must to be conserved and made "ecologically sound" in order to prevent further biodiversity loss.
See also
* Biodiversity loss
* Extinction Rebellion
* Extinction risk from climate change
* Extinction symbol
The extinction symbol represents the threat of holocene extinction on Earth; a circle represents the planet and a stylised hourglass is a warning that time is running out for many species. The symbol dates to at least 2012 and has been attribu ...
* ''Extinction: The Facts'' (2020 documentary)
* Human impact on the environment
Human impact on the environment (or anthropogenic impact) refers to changes to biophysical environments and to ecosystems, biodiversity, and natural resources caused directly or indirectly by humans. Modifying the environment to fit the need ...
* Lists of extinct species
* Pleistocene rewilding
* Quaternary extinction
* ''Racing Extinction'' (2015 documentary film)
* Timeline of extinctions in the Holocene
* World Scientists' Warning to Humanity
Notes
References
Further reading
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External links
The Extinction Crisis
Center for Biological Diversity.
Vanishing: The extinction crisis is far worse than you think
CNN. December 2016.
Biologists say half of all species could be extinct by end of century
''The Guardian,'' 25 February 2017
''The Independent,'' 31 May 2017
Human activity pushing Earth towards 'sixth mass species extinction,' report warns
CBC. Mar 26, 2018
‘Terror being waged on wildlife', leaders warn
''The Guardian.'' October 4, 2018.
Earth Is on the Cusp of the Sixth Mass Extinction. Here’s What Paleontologists Want You to Know
''Discover
Discover may refer to:
Art, entertainment, and media
* ''Discover'' (album), a Cactus Jack album
* ''Discover'' (magazine), an American science magazine
Businesses and brands
* DISCover, the ''Digital Interactive Systems Corporation''
* D ...
''. December 3, 2020.
{{DEFAULTSORT:Holocene Extinction
Species made extinct by human activities
Extinction
Extinction
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the Endling, last individual of the species, although the Functional ext ...
Extinction
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the Endling, last individual of the species, although the Functional ext ...
Environmental impact by effect
Human ecology
Human impact on the environment
Anthropocene
Extinction events
hu:Pleisztocén-holocén becsapódási esemény