The sixth mass extinction in Earth's history has already begun. Due to the fact that some animals and plants will disappear, people will also be seriously affected. However, there is still time to prevent this, American scientists say.
In the history of the Earth, there have been five periods of mass extinctions when the rate of extinction of species was much higher than usual. Among them is the extinction of dinosaurs that occurred 65 million years ago, which, however, is significantly inferior in scale to the mass Permian extinction: it happened about 252.2 million years ago - then almost 95% of the species that inhabited our planet disappeared.
Thus, over the past 65 million years, there has not been the slightest hint of another mass extinction. And this is despite the notorious anthropogenic factor, which was attributed to a catastrophic impact on the flora and fauna of the planet.
However, researchers from Stanford University claim that the Earth is currently experiencing one of the early stages of another mass extinction. They shared their observations in a review that was published in the latest issue of the scientific journal Science. Their publication caused a wide response and attracted the attention of many popular science portals, such as LiveScience.
According to scientists, the planet is now experiencing a peak in biodiversity for 3.5 billion years of life on it.
Five mass extinctions in Earth history
However, alarming signals began to arrive long before the start of the industrial revolution: since 1500, about 320 species of terrestrial vertebrates have become extinct. And the populations of the remaining species have decreased by a quarter. Moreover, of the living vertebrates, about 33% of the species are endangered. The situation is especially dangerous with representatives of the megafauna - elephants, giraffes, hippos and other large animals.
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Despite the fact that there are not so many large animals on the planet, their disappearance is accompanied by catastrophic consequences. So, in Kenya, in areas where elephants, giraffes and zebras used to live, rodents found shelter. And this, in turn, contributes to the uncontrolled eating of grass and bushes.
The result of this is soil compaction, and as a result, a decrease in yield, and subsequently desertification of vast territories. And the huge population of rodents carries many diseases. Since there are no predators, there is no one to control the number of rodents and to destroy sick individuals.
Scientists have not forgotten about invertebrates: over the past 35 years, their number has decreased by 45%. This trend is especially dangerous in light of the fact that insects pollinate about 75% of the world's food crops. In addition, insects play an important role in nutrient cycling and organic degradation. The United States alone spends $ 4.5 billion annually on the fight against predators that destroy such insects, which helps to understand the scale of the problem.
“In a global sense, extinction is the loss of a particular ecosystem. However, now the extinction of certain species is directly threatening people. While there is time to try to change something,”says Professor Rodolfo Dirzo, who is one of the authors of the review.
The previous study on the sixth mass extinction was published in the journal Nature. Then scientists were sure that the mass extinction had not yet begun, but would certainly happen in the next 2 thousand years. The researchers named 300 years as the earliest date. Be that as it may, people need to try to change the current situation now.