Home >science >health >Sixth mass extinction of species has already begun: study

New Delhi: The sixth mass extinction of species is underway thanks to factors like overpopulation and overconsumption, and there is little time left for effective action, a study claimed.

As much as 50% of the number of animals that once shared the Earth with humans are already gone, and the next two decades will see more powerful assaults on biodiversity, according to the study published in the July edition of Proceedings of the National Academy of Sciences, a US scientific journal.

The study, titled “biological annihilation via the ongoing sixth mass extinction signalled by vertebrate population losses and declines", said humanity will pay a very high price for this loss, adding that the time for effective action is very short—probably two or three decades. British newspaper The Guardian reported on the study on Monday.

The authors of the study—Gerardo Ceballos of Mexico-based Instituto de Ecología and Stanford University’s Paul R. Ehrlich and Rodolfo Dirzo—said their analysis is conservative, but given the increasing trajectories of the drivers of extinction, “future losses easily may amount to a further rapid defaunation of the globe and comparable losses in the diversity of plants".

Using a sample of 27,600 terrestrial vertebrate species and a more detailed analysis of 177 mammal species, the study shows “extremely high degree of population decay in vertebrates, even in common species of low concern".

It emphasized that in the last few decades, “habitat loss, overexploitation, invasive organisms, pollution, toxification, and more recently climate disruption, as well as the interactions among these factors" have led to the catastrophic declines in both the numbers and sizes of populations of both common and rare vertebrate species.

Several species of mammals that were relatively safe one or two decades ago are now endangered. For instance, in 2016, there were only 7,000 cheetahs in existence and less than 5,000 Borneo and Sumatran orangutans. Similarly, populations of the African lion has dropped by 43% since 1993, pangolin populations have been decimated and populations of giraffes dropped from around 115,000 individuals in 1985 to around 97,000 in 2015.

“Population extinctions today are orders of magnitude more frequent than species extinctions. Population extinctions, however, are a prelude to species extinctions, so Earth’s sixth mass extinction episode has proceeded further than most assume... The sixth mass extinction is already here," it said.

As per the study, the immediate causes of this biotic destruction are “human overpopulation and continued population growth, and overconsumption, especially by the rich".

The study warned that the window for effective action is very short, “probably two or three decades at most".

“All signs point to ever more powerful assaults on biodiversity in the next two decades, painting a dismal picture of the future of life, including human life," it added.

Calling it a “frightening assault on the foundations of human civilization", the study said this biological annihilation obviously will also have serious ecological, economic, and social consequences.

Stating that the massive loss of populations is already damaging the services ecosystems provide to civilization, it said, “humanity will eventually pay a very high price for the decimation of the only assemblage of life that we know of in the universe".

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