Sixth mass extinction expected due to climate change and floods


Of all the species to ever live on planet Earth, more than 90 percent are estimated to be extinct by biologists. Most of these species perished over the past half-billion years in one of the five major mass extinctions, which were the Ordovician-Silurian mass extinction, which was the third largest extinction in Earth’s history; the Late Devonian mass extinction, where three quarters of all species on Earth died out; the Permian-Triassic mass extinction, where 96 percent of species died out; the Triassic-Jurassic mass extinction, where there was climate change and the Cretaceous-Tertiary mass extinction, where dinosaurs were killed.

Now, the world is in the middle of a sixth extinction. The greatest tragedy of this extinction is that it is distressingly of our own making. In The Sixth Extinction: An Unnatural History, author Elizabeth Kolbert reveals the planetary crisis through emotionally heartbreaking current events on endangered species and their fate of extinction caused by humanity’s ways.

Kolbert, a journalist who is curious about man’s relationship with nature, reads an article that suggests Earth is moving toward mass extinction.

To see indications of mass extinction, she travels the world. Her journey uncovers what species are endangered, what the starting points for mass extinction are and what preventive measures are installed to overcome this issue.

Kolbert opens the reader’s eyes to how influential and destructive human beings are, and how they are affecting every species on the planet.

Kolbert emphasizes how irrelevant human civilization history is in the grand scheme of time when

she writes, “If all civilizations were to end up together, then 100 million years hence, everything we have built would be compressed, in the geological record, to a layer of sediment ‘not much thicker than a cigarette paper.’”

There is no denying that, as a species alone, human beings are affecting Earth’s environments, just like comets striking the planet, the rapid rise in oxygen levels or anything else that changes the rules of life across the board.

Kolbert also highlights the beliefs about extinction from well-known naturalists. Charles Darwin described in his journalistic writings in On the Origin of Species that, “Evolutionary processes produce new species at an incredibly slow yet steady rate. Species also go extinct at a slower rate which is referenced as the background extinction rate. An extinction even it is a relatively rapid decrease in the number of extant, living species.”

Kolbert learns fundamental facts about extinctions on her travels.

During any extinction in natural history, the number of species dying is unusually high when compared to the “background extinction” rate, which is the more natural cause of these deaths.

A background extinction is a natural process where the extinction of one species takes hundreds of years. Background extinction is derived from the theory of evolution.

On the other hand, the losses of a “mass extinction” are fast and destructive. For example, the Cretaceous period, which happened about 65 million years ago,  is recognized as the period when the dinosaurs went extinct.

Scientists and biologists use different ways to try and estimate current rates of extinction and how to

classify them.From a biological standpoint, any communities and ecosystems that have more diversity at the species level will be more resistant to rates of extinction.

The meaning of this is hard to predict. There will be a lack of foundation for food chains and thousands of ecosystems will be harmed and lost.

New species will flourish with the loss of predators and the absence of competition.

For human beings and predators, this is incredibly dangerous because apex predators, or animals who have no natural predators in their ecosystem, depend on complex, large networks of food webs to survive.

The lack of genetic diversity is another issue that arises from the extinction of species.

The bottleneck effect, or when

a population declines in size due to environmental effects such as floods, causes the lack of genetic diversity and huge losses in genetic varition.

Kolbert’s publication does not only deliver a sense of doom, but also a good view on how climate change affects species.

For example, the greak auk, a flightless bird that became extinct in the mid-nineteenth century; the moa, nine species of which became extinct 1,000 years ago and the broad-faced potoroo, a marsupial that became extinct in 1875.

But, in Kolbert’s words, there is a possible way to change.

“Obviously for the animals that have already gone extinct, it’s too late. And it’s probably also too late for the many, many species that are now down to their last few hundred individuals. But it’s probably not

too late for hundreds of thousands, maybe millions of other species. I think one of the most important things people can do is become politically engaged. I know this can sound like an excuse, but these are huge problems that can’t be addressed on a small scale. I think getting involved with land preservation is also an extremely useful thing to do. As the world changes, species are on the move, and they need somewhere to go. The more land we essentially put aside for them, the more is likely to survive,” Kolbert said.

Kolbert explained that not only are humans contributing to the species’ road to extinction, but they are also contributing to the destruction of habitats.

However, she suggests that there is hope for the planet, and hope to recover from the sixth extinction.