What is the sixth mass extinction, what scientists say


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Recent research published in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS), indicates that the current sixth mass extinction could be one of the most serious environmental dangers to the survival of the civilization.

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According to the study, this extinction is caused by humans and is more imminent than climate change. “Even though roughly 2% of all species that ever lived are alive today, the total number of species is now greater than it ever was.” We humans have evolved into such a biologically rich planet, and it is this world that we are destroying, the study added.

What is the mass extinction of species?

Extinction is a natural part of existence, and creatures and plants go extinct on a regular basis. About 98 percent of all species that ever lived on our planet are extinct. Earlier in geological time, massive extinctions occurred.

Mass extinction event
Reuters

Many species can be wiped out by anything from a meteor collision to climate change or a volcanic eruption. Essentially, mass extinction occurs when the degree of extinction increases significantly, or when the Earth loses more than three-quarters of its species in a geologically short period of time. This is generally characterized as the extinction of about 75% of the world’s species in a short period of geological time – less than 2.8 million years.

When a species becomes extinct, its ecological niche is frequently fueled by new or existing species. The “normal” rate of extinction on Earth is estimated between 0.1 and 1 species per 10,000 species per 100 years. This is called the background extinction rate.

These extinctions were triggered by “catastrophic changes” to the environment, such as massive volcanic eruptions, depletion of ocean oxygen, or an asteroid impact. These incidents are a testament to the tenacity and resilience of life. Life seems to take many forms, diversify and change, but it always comes back. The extinction of a single species or family creates evolutionary niches which lead to the diversification of another.

What is the sixth mass extinction?

The so-called “mass extinction event” – only the sixth in the past half a billion years – is already underway. And it’s called the extinction of the Anthropocene.

Scientists believe that there are eight million different species on Earth today, most of which are insects. Already, a quarter of all animal and plant species are overpopulated, eaten or poisoned to extinction.

About 30% of all wild trees are currently threatened with extinction, revealing report says
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The decline in raw numbers is even more extreme, with wild mammal biomass (their total weight) declining by 82 percent. Humans and livestock make up over 95% of mammalian biomass.

This global extinction has been described as the “most catastrophic environmental disaster” because the loss of species will be irreversible. The study analyzed 29,400 species of terrestrial vertebrates to see which are on the verge of extinction because they have fewer than 1,000 individuals.

They found that more than 515 of the species studied are very close to extinction and that the current loss of species, which is based on the absence of their component populations, has continued since the 1800s.

South America accounts for the majority of the 515 species (30 percent), followed closely by Oceania (21 percent), Asia (21 percent) and Africa (16 percent).

In addition, the study points out that more than 400 species of vertebrates have become extinct over the past century, extinctions that would have taken 10,000 years in the normal course of evolution. In a study of 177 large mammal species, the majority have lost more than 80% of their geographic range in the past 100 years, and 32% of the more than 27,000 vertebrate species have declining populations.

More than 30% of shark species are now threatened with extinction, IUCN update
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What is more alarming is that extinctions today are hundreds of times faster than they would have occurred spontaneously in the past. If all critically endangered, endangered or vulnerable species become extinct within the next century, and if the rate of extinction does not decline, humanity could be on the verge of mass extinction in 240 to 540 years. barely.

Significantly, the report calls for a complete ban on wildlife trade, legal and illegal wildlife trade is wiping out many species that are currently threatened or on the brink of extinction. The researchers also point out that the current COVID-19 pandemic, while not fully understood, is also linked to the wildlife trade.

Climate change is a long-term danger. By injecting billions of tons of carbon dioxide and other chemicals into the Earth’s atmosphere annually, humans have been able to chemically replicate vast igneous provinces.

These historic volcanoes produced much more CO2 than humans today in terms of total volume; Siberian traps released more than 1,400 times the CO2 humans released in 2018 by burning fossil fuels for energy. Humans, however, generate greenhouse gases at the same rate as the Siberian traps, if not faster, and Earth’s climate is changing rapidly as a result.

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As the mass extinctions have demonstrated, abrupt climate change can be extremely disruptive. And just because we haven’t reached the 75% threshold of catastrophic extinction doesn’t mean that all is well.

The devastation would wreak havoc on the ecosystems we inhabit long before this worrying threshold is reached, endangering species around the world, including humans.

How many mass extinctions have there been?

So far, the face of life on Earth has been changed by five major mass extinctions. Some of them have a known cause, but others remain a mystery. Geologists have identified and examined these major occurrences. These extinctions over the past 450 million years have resulted in the extinction of 70 to 95 percent of all plant, animal and microbial species that previously existed.

443 million years ago, the Ordovician-Silurian mass extinction wiped out nearly 85% of all species. Temperatures dropped and massive glaciers formed, causing sea level to drop drastically, scientists said. After that, there was a period of rapid warming. Many small marine animals perished.

Climate change
Unsplash / Representative Image

The Devonian mass extinction occurred 374 million years ago, killing about three-quarters of the world’s species, the majority of which were marine invertebrates that lived on the bottom of the sea.

Numerous climate changes occurred during this period, including global warming and cooling, sea level rise and fall, and decreased levels of oxygen and carbon dioxide in the atmosphere. However, the reason for the extinction catastrophe is not yet known.

The Permian mass extinction, which occurred 250 million years ago, was the most massive and destructive of the five. It wiped out over 95 percent of all species, including most of the vertebrates that had started to evolve around this time. He was also known as the Grand Mourant.

Some scientists believe Earth was hit by a massive asteroid, which deposited dust particles in the atmosphere, blocking the Sun and causing acid rain. Others believe there was a major volcanic eruption that released carbon dioxide into the atmosphere, making the waters toxic.

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The Triassic mass extinction occurred 200 million years ago, wiping out over 80% of Earth’s biodiversity, including many species of dinosaurs. This was likely caused by massive geological activity, which increased CO2 levels, global temperatures, and ocean acidification.

The Cretaceous extinction occurred 65 million years ago, resulting in the disappearance of 78% of all species, including all non-avian dinosaurs. This was likely caused by an asteroid hitting Earth in what is now Mexico, with continued flood volcanism in what is now India compounding the problem.

For more news and updates from around the world, please visit Indiatimes News.

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