The Sixth Extinction by Elizabeth Kolbert [Book Summary]

Our planet has gone through five disastrous extinction of species, a series that scholars named “big five”. For instance, the extinction of dinosaurs was part of these 5.

Still, nowadays although you look through this currently, a 6th extinction is occurring. We are all to blame for it.

Humans are to blame, through deforestation, industrialization, and the subsequent transformations in climate, for accelerating the extinction process for a severe amount of species among animals. Oceans became more acidic; habitats have transformed; biodiversity has reduced to disturbing levels.

Therefore, what can we do? Is there a way for us to change the course and re-establish some kind of equilibrium in the earth? These book chapters will describe the way we have had a part to place in the extinction of species starting with Homo sapiens initially throwing a lance, and the way if we will not transform our ways, we might just go the Neanderthal path.

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Chapter 1 – Our way of life and the way we wander around the world have directly led to extinctions in animal species.

Presently, a lot of species of animals are threatened. Specific animals are endangered with extinction. 

Still, did you think of how precisely a species vanishes from our world?

Historically, disappearances are uncommon and happen really slowly. Still, there were times of transformations in the environment that initiated mass extinctions, where a lot of species die within a shortened period of time.

Therefore, although the “normal” level of disappearance – the normal extinction rate – has usually been slow, it varies according to the types of animals.

For example, from the normal extinction rate of mammals, people need to anticipate witnessing a species become extinct each seven hundred years. However, during mass extinction, that level increased. Until now we know of five of that kind of incident of which the scientific society names “big 5.” For instance, the disappearance of dinosaurs about sixty-four million years previously was part of the 5.

However, mass extinctions are not only restricted to ancient times. As a matter of fact, people may be going through one at the moment. We understand this by checking the real level of extinction of species.

Consider amphibians, a very threatened type of animal. Presently, amphibians’ real level of extinction has been calculated as 45000 multiples than the normal level!

Therefore, the inquiry is: What is the cause of this calamity?

The real cause is humans. People are both, indirectly and directly, blamable for the disappearances of species.

Think of the present-day transportation networks. Planes, trains, and ships crisscross the world, linking landmasses and incidentally leading to mass disappearances by bringing novel structures into surroundings in which they may cause disaster on present species populations.

For example, the golden frogs of Panama, now battle against a dangerous fungus that probably came from Europe to their area. However, other species like the spear bird have directly been exterminated by hunters and by changes done to their area.

Therefore, we are the cause of this havoc. However, was there a way for us to understand what a deep consequence our behaviors might bring to the world? In order to understand more, let’s examine the past of extinction and evolution.

Chapter 2 – Disappearance: fast or slow? Theories have evolved over hundreds of years as novel evidence is discovered.

The notion that species can decline and disappear completely is quite new. As a matter of fact, people have assumed for a period that species in the world would stay the same all the time.

Therefore, what was the time we eventually knew the changing structure of endurance around the kingdom of animals?

Back then, during the 19th hundredth year, Georges Cuvier, a naturalist from France hypothesized that animal types could go into extinction via cataclysmic transformations in the environment.

However, Cuvier’s hypothesis was challenged by Charles Lyell a British geologist, who claimed that extinction happens at the exact same speed as the environmental transform. He then mentioned that when surroundings transformed slowly; therefore, extinctions as well would happen slowly – an idea chosen over Cuvier’s hypothesis of calamity.

However, during the 1980s Cuvier’s hypothesis got much traction during that time when Walter Alvarez, a geologist basically discovered new evidence.

While examining a part of the earth that matched with the closure of the time of Cretaceous, a time that finished about 66000000 years previously, Alverez discovered that it had a strange number of iridium, an unusual earth metal discovered mostly in meteorites.

According to this finding, Alvarez proposed a concept to describe the conditions causing dinosaurs’ disappearance. He named his concept “impact theory”.

This theory states that a lot of times ago, a 10-km meteor struck our world; its influence collected a lot of dust that covered the sun, causing the terrible transformation of climate and the fast death of a lot of dinosaur species.

Based on the present research, four out of “big 5” mass disappearances were fascinatingly an outcome of the transformation of climate prompted by changes of our world’s orbit, as a result of the pull of gravitation from further globes around the solar structure.

Still, we understand that humans had a part to play in species disappearance as well. However, in what way?

Chapter 3 – The structure of extinction in species has been accelerated by Carbon, via a climate that is getting hot.

In order to know the reason we would be in the sixth stage of mass extinction in species, we have to know the things that have been made to transform environments–and industrialization is the main cause.

For example, industrial CO2 releases have extremely increased acid in oceans, and that has caused biodiversity to decline.

However, how did this occur precisely?

The atmosphere and oceans are in continuous exchange: gases that are around our atmosphere break down into the water, and the gases that dissolve from oceans get into the air. Therefore, the rising grade of CO2 around our atmosphere has also been increasing the quantity of CO2 present within oceans.

Still, an acid is formed at times CO2 mixes with water. Various studies have demonstrated that oceans increased in acid 30% more than the time industrialization began during 1700.

Becoming more acidic has been an issue for lots of species. This is because acidification alters the nutrient structure of the ocean; hence, decreasing common biodiversity, since specific species can’t get sufficient food to eat. Still, calcifiers, which is an organism having a skeleton externally or a shell, are the ones that have the biggest risk.

Higher grades of acid around oceans signify decreased grades of carbonate and calcium ions, which are the components of outside skeletons and shells. Organisms will die if they can’t form a protective.

However, that’s isn’t the only issue. Also, CO2 has been one of the greenhouse gasses that leads to global warming – an extreme issue with consequences that spread well beyond problems for species living in cold climates.

Established, if a habitat becomes really hot, animals might basically move to a place that is colder. However, there’s an issue: although the cooler habitats around the world, like the places polar bears stay, are vanishing.

The unforeseen levels that our world is getting hotter signifies that endangered types that could move to colder climates will currently pass away prior to getting an environment to stay.

Also, rising CO2 grades have been an extreme issue for the disappearance of species. However, that isn’t the only means humans are accelerating extinction.

Chapter 4 – With Automobiles, planes, and trains, we have been able to travel around the world, to risk endangered species.

Additionally to CO2, the unfavorable consequences of contemporary transportation structures and deforestation are key elements adding to the extinction of species.

Through deforestation, we damage the habitats and we basically pressure species to lesser groups of the population that become more endangered afterward, and perhaps to become vulnerable or disappear.

Assuming only one female and only one male in a certain type are in existence, at the time either die, this would cause trouble for the whole species. This is why islands normally have less diversity in species than mainland habitats do.

Also, that is the exact cause of why deforestation has been a danger to biodiversity. It has been estimated by scientists that diminishing forests signify the disappearance of nearly five thousand species each year. This calculation estimates that the earth’s tropical forests, which is a habitat to 2000000 species, reduce yearly in dimension by 1%.

Another issue is how easy it is for us to travel. But, by traveling, we assist in redistributing types around the world, which homogenizes current species while decreasing common biodiversity.

What is the way this works precisely?

According to Charles Darwin, limitations of geography were crucial to clarify the reasons why areas of our earth that had the same climates like Oceania, Africa, and Latin America were habitats to completely different species.

Still, during the late 19th hundredth year, paleontologists discovered an unusual association between fossils on various landmasses. The last hypothesis on continental drift could clarify this association: that the earth’s landmasses were linked, creating one single landmass known as Pangea.

Basically, contemporary technology has rebuilt these old bridges of land. The structure in which animals and plants were laid out was dependent on the leisurely attempt of people’s migration; nowadays, things move very fast and more often.

Due to that, habitats have started joining while breeds that formerly existed safely by themselves are currently endangered with rival life forms and can vanish completely.

However, although contemporary transportation and deforestation have influenced the level of disappearance, we people have been supporting disappearance starting with our initial evolution.

Chapter 5 – Wooly mammoth’s disappearance was not the only thing homo sapiens caused; however, maybe they caused the extinction of our relatives as well.

It’s not only the activities of humans starting with the industrial time that has led to mass disappearances of species. As a matter of fact, people have caused extinctions since the root of people’s type, Homo sapiens.

Big mammals like the rhinoceros increase in number slowly; however, their size defends them from the majority of the natural predators – to be exact, apart from people predators. Therefore, as people’s race moved across the recent millennia and started hunting, the number of the world’s big animals reduced.

Some researchers guessed that these declines were caused by climate change; however, the association was difficult to prove. But, the thing they discovered and effortlessly proved, was that in the place where humans stayed, big animals died all at once.

Humans have been huntsmen from the very start. Species such as wooly mammoths didn’t have any natural hunters until people got into the picture! All of a sudden these big beasts were endangered, and their living structures were not effective anymore.

Homo sapiens were involved in the disappearance of Neanderthals as well. At the time Homo sapiens went to places where Neanderthals existed, they started to vanish.

However, prior to the death of the final Neanderthal, Homo sapiens grew with those. Due to that, presently, some 4% of the population of humans owns Neanderthal heredity! That is particularly correct around Eurasia, the previous home of Neanderthals. 

While the Neanderthals often stayed around Eurasia, that was different for Homo sapiens who journeyed far, getting to untouched areas of the earth like the distant islands around the ocean.

Could you think of the number of people that depart just to be missing in the sea prior to Easter Island being eventually found? Maybe it is that risk-seeking action that clarifies the achievement of our type rather than the near relatives’ Neanderthals.

Therefore, fascinatingly, although people have been the reason for the 6th mass disappearance, they might also be part of the victims. However, the severe natural transformations we have produced might be what carries us to the path of Neanderthals.

The Sixth Extinction: An Unnatural History by Elizabeth Kolbert Book Review

With people’s arrival on the earth, we have encouraged the disappearance of species other than ourselves. But, the natural transformations we have created have done increasingly destruction in the last hundred years. If people do not transform their approaches soon enough, it could signify the end of people’s development itself.

For additional resource: Mitigating Climate Change: Its Starts With Better Ocean Data

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Savaş Ateş

I'm a software engineer. I like reading books and writing summaries. I like to play soccer too :) Good Reads Profile:

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