The Holocene extinction. Sixth mass extinction caused almost exclusively by humans

The sixth mass extinction event on earth is currently underway and this time it's been caused by... you guessed it. Humans. Named the Holocene extinction it refers to the current ongoing extinction event we face at this time.

A team of researchers at Aarhus University have found that mammal species that call earth home are going extinct so fast that natures defense mechanism Evolution can't manage to keep up.
In the past 450 million years we have had 5 separate mass extinctions as sighted by scientists and we are currently entering the 6th. Estimates show that if we do not do something to curb the damage or improve conservation it will take 3-5 million years for nature to recover.

What is a mass extinction

Mass extinctions occur when the environment of earth changes dramatically in a small amount of time, leaving many species unable to evolve fast enough to keep up with the change. This leads to a large percentage of plant and animal species going extinct.
Mass extinction events are defined when the rate of extinction goes far beyond the regular background rate of extinction.

Previous mass extinction events

In the last half billion years there has been 5 other known mass extinction events. The difference is they were caused by natural disasters such as massive volcanic eruptions or supervolcanoes, asteroid impacts and natural climate shifts.

At current 99% of threatened species are that way because of humans, mostly through habitat loss.

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Certain animals that are going extinct are more evolutionarily significant.

If you look at some of the species facing extinction such as the shrew, we find they have hundreds of species alive today so their lineage can survive an extinction or two. However when it comes to animals like the elephant and the rhino they are far more evolutionary distinct, there are very few species left, if the few that are left go extinct we will lose entire branches of their evolutionary tree that may never be rediscovered.

Yes extinction is a natural phenomenon

Species die out at a "background rate" of between one and five species a year. Current estimates put the extinction rate now between 1,000 and 10,000 times that. A pace that, if not countered in some way will result in the loss of between 30 and 50% of our current species by mid century.
This is a clear indication of the damage done by humans and the impact we have managed to have in such a small amount of time.

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The last mass extinction

Our last mass extinction occurred about 65 million years ago, most notably responsible for the disappearance of the dinosaurs but in total wiped out 3/4 of the earths plant and animal species at the time.
Known as the Cretaceous–Paleogene extinction event. As originally proposed most evidence points to this being the result of a massive asteroid or comet strike resulting in a lingering impact winter.
The obvious difference being this was a naturally occurring event whereas the current extinction event is caused almost exclusively by humans.
Not only are we making it difficult for species to simply survive but we are creating a greater threat to already at risk species.

Did you know only 3% of the worlds animals are wildlife?

Since 1970 wildlife has decreased by almost 50%. With over 97% of all the animals on earth being either humans, livestock or pets. This is caused by direct hunting and global scale habitat destruction, given half of earth has been turned into farmland this isn't hard to imagine.
But the oceans, they have suffered just as much. Each year fishing trawlers plow an area of seafloor twice the size of the continental United States destroying massive swathes of ecosystem and leaving nothing bur barren sea floor. They are responsible for the destruction of over 90% of all large marine predators and a staggering 270,000 sharks are killed everyday.

There is debate as to whether this is considered a mass extinction

"People who claim we’re in the sixth mass extinction don’t understand enough about mass extinctions to understand the logical flaw in their argument,”. “To a certain extent they’re claiming it as a way of frightening people into action, when in fact, if it’s actually true we’re in a sixth mass extinction, then there’s no point in conservation biology.”
Paleontologist Doug Erwin

Whilst true it is significantly different and possibly slower than other mass extinctions this is still the mass wipe-out of a majority of species on earth in a very short time-frame.

He does have a point though, if this is a mass extinction then we may already be too late to do anything.

resources

https://www.theatlantic.com/science/archive/2017/06/the-ends-of-the-world/529545/
https://www.sciencedaily.com/releases/2018/10/181015154435.htm
https://www.biologicaldiversity.org/programs/biodiversity/elements_of_biodiversity/extinction_crisis/
https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event