January 16, 2017 Biodiversity No Comments
Life on the brink of a sixth mass extinction
Change is a natural and inevitable part of

life on our planet. But some radical changes have marked our planet and defined its further evolution. Indeed, among other things, the Earth has lived through a series of mass extinction events where the majority of species inhabiting our planet perished. The most well-known mass extinction was the Cretaceous-Tertiary, also known as the K-T extinction event, which wiped out dinosaurs¹. This was not a singular event in our planets history; scientists have been able to identify at another four occasions when life on our planet was eliminated to an even greater degree than what happened with dinosaurs. For example, around 252 million years ago the Permian mass extinction – nicknamed The Great Dying –  resulted in the death of 96% of species. Life on Earth today can be traced back to the 4% of species that survived¹,². What is more, some of these mass extinction events cannot be attributed to a single event, such as an asteroid impact. In the case of the Late Devonian mass extinction, it is estimated that there were a series of extinctions that took place over several million years¹.

Most of us will think that those events are buried deep in our planet’s history and can only serve to pique our interest or serve as inspiration for a sci-fi book or movie! However, we are actually on the brink of a sixth mass extinction. Scientists have confirmed that today plants and animals are dying about 1,000 times faster compared to before humans inhabited the earth. The study updated previous scientific facts which had indicated a lower rate of extinction; new research now revealed that species are in fact disappearing 10 times faster than what experts believed so far³.

One of the key research papers supporting that we are on the brink of a sixth mass extinction was co-authored by Stanford biologist Paul Ehrlich in association with colleagues from the University of Princeton, Berkley and others. It shows that even with extremely conservative estimates, species are disappearing up to about 100 times faster than the normal rate between mass extinctions,. If this rate of extinction continues, life on Earth would take many millions of years to recover and humans are likely to be one of the species that would likely disappear early on, stated lead author Gerardo Ceballos of the Universidad Autónoma de México.

Other data though are supporting evidence that we are living through a mass extinction. Over the past 500 years, we know of approximately 1,000 species that have gone extinct – these species greatly vary and were found in different regions. Examples include the woodland bison of West Virginia and Arizona’s Merriam’s elk to the Rocky Mountain grasshopper, the passenger pigeon and Puerto Rico’s Culebra parrot. This staggering number of 1,000 extinct species does not take into account species that have disappeared but had not been recorded. So the number of species that have gone extinct is most certainly not revealing the full picture. Conservation scientist David Wilcove estimates that there are 14,000 to 35,000 endangered species in the United States, which amounts to 7-18% of U.S. flora and fauna. The IUCN has assessed roughly 3% of known species and identified 16,928 species worldwide as being threatened with extinction, or roughly 38% of those assessed.

This certainly paints a very bleak picture for our future. Biodiversity and species are essential to preserving life on our planet, including our own life. This is why the international community has taken steps and set targets for reversing biodiversity loss. However, we are still behind in terms of progress towards meeting that goal.

On a more positive note, experts are still confident that we can avert a dramatic decay of biodiversity and the subsequent loss of ecosystem services, such as pollination, water purification and so many others, through intensified conservation efforts. But we have only a small window of opportunity to do so and this is rapidly closing. To alleviate the pressures on our fauna and flora, we need to start reversing habitat loss, start producing more sustainably, eliminate toxic chemicals and address climate change. These are certainly very tall orders. But the reality is that we do not have any alternatives if we want to preserve life on this Earth in the future.

 


References

¹ http://www.bbc.co.uk/nature/extinction_events
² https://goo.gl/ut1VvD
³ https://goo.gl/EJ3LNg
http://advances.sciencemag.org/content/1/5/e1400253
http://news.stanford.edu/2015/06/19/mass-extinction-ehrlich-061915/
https://goo.gl/RV5HUi

Written by Greentumble Editorial Team