Global Geological And Climatic Events

The Sixth Mass Extinction

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Sixth Mass Extinction

Mains level : Mass Extinction

Click here for high resolution of the image: National Geographic

The ongoing sixth mass extinction may be one of the most serious environmental threats to the persistence of civilization, according to new research published in an American journal.

Try this question from CSP 2018:

The term “sixth mass extinction/sixth extinction” is often mentioned in the news in the context of the discussion of

(a) Widespread monoculture Practices agriculture and large-scale commercial farming with indiscriminate use of chemicals in many parts of the world that may result in the loss of good native ecosystems.

(b) Fears of a possible collision of a meteorite with the Earth in the near future in the manner it happened 65million years ago that caused the mass extinction of many species including those of dinosaurs.

(c) Large scale cultivation of genetically modified crops in many parts of the world and promoting their cultivationin other Parts of the world which may cause the disappearance of good native crop plants and the loss offood biodiversity.

(d) Mankind’s over-exploitation/misuse of natural resources, fragmentation/loss, natural habitats, destructionof ecosystems, pollution and global climate change.

Highlights of the research

  • The study analysed 29,400 species of terrestrial vertebrates and determined which of these are on the brink of extinction because they have fewer than 1,000 individuals.
  • The disappearance of their component populations has been occurring since the 1800s.
  • Most of these 515 species are from South America (30 per cent), followed by Oceania (21 per cent), Asia (21 per cent) and Africa (16 per cent) among others.

The Anthropocene Extinction

  • Mass extinction refers to a substantial increase in the degree of extinction or when the Earth loses more than three-quarters of its species in a geologically short period of time.
  • So far, during the entire history of the Earth, there have been five mass extinctions.
  • The sixth, which is ongoing, is referred to as the Anthropocene extinction.
  • The five mass extinctions that took place in the last 450 million years have led to the destruction of 70-95 per cent of the species of plants, animals and microorganisms that existed earlier.
  • These extinctions were caused by “catastrophic alterations” to the environment, such as massive volcanic eruptions, depletion of oceanic oxygen or collision with an asteroid.
  • After each of these extinctions, it took millions of years to regain species comparable to those that existed before the event.

So what is the sixth mass extinction then?

  • Researchers have described it as the “most serious environmental problem” since the loss of species will be permanent.
  • Even though only an estimated 2% of all of the species that ever lived are alive today, the absolute number of species is greater now than ever before.
  • The research claims that this extinction is human-caused and is more immediate than climate destruction.

Major drivers of mass extinction

  • Significantly, the study calls for a complete ban on wildlife trade as many of the species currently endangered or on the brink of extinction are being decimated by legal and illegal wildlife trade.
  • The current COVID-19 pandemic, while not fully understood, is also linked to the wildlife trade.
  • There is no doubt that there will be more pandemics if man continues destroying habitats and trading wildlife for own consumption as food and traditional medicines.

What happens when species go extinct?

  • When species go extinct, the impact can be tangible such as in the form of a loss in crop pollination and water purification.
  • Further, if a species has a specific function in an ecosystem, the loss can lead to consequences for other species by impacting the food chain.
  • The effects of extinction will worsen in the coming decades as the resulting genetic and cultural variability will change entire ecosystems.
  • If the number of individuals in a population or species drops, their contributions to ecosystem services become unimportant.
  • Their genetic variability and resilience is reduced, and its contribution to human welfare may be lost.” the study says.
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