Has Earth Hit its 6th Mass Extinction? Henry Wang

Throughout all of Earth’s history, species have come and gone, with 99% of all species that ever lived on Earth extinct (4 billion). While this number shouldn’t be much of a worry as life on Earth has been around for around 3.5 billion years, the rising number of extinctions due to humanity can show that we might be taking a turn for the worst. Nature was never forgiving, with animals going extinct being a common occurrence. However, climate change (deforestation, fossil fuels, etc.) has caused the rate of extinction to be much higher than it should, shrinking the biodiversity of our planet essential to its ecosystems. With the excess amount of species dying off every year, ample evidence points to the fact that we are touching, if not already swimming through the 6th mass extinction.

Why is it called the 6th mass extinction in the first place? Well obviously because it is the 6th with five preceding, but in order to comprehend how big a mass extinction truly is, we need to compare the difference between mass extinctions and background extinctions. A background extinction is the gradual, slow, and frequent extinction of any species, such as a predator failing to adapt to a new environment. A mass extinction, however, is a sudden, rapid, and extreme increase in the extinction of all species, a decrease in biodiversity. 

The first mass extinction can be related to current-day news, global warming. The Ordovician-Silurian Extinction (440 Million years ago) was caused by large amounts of plants removing CO2 resulting in a temperature drop, and then the drop causing a decrease in habitat deductions, resulting in global warming (yes it has happened before) and sea levels rising. Others following is shown in this infographic demonstrate how dynamic (in terms of temperature) our Earth is, with both rising and falling in temperatures resulting in the extinction of many species. The more recent extinction event was the Cretaceous-Paleogene Extinction, which wiped out the dinosaurs (big asteroid go boom) showing that it's not just internal factors that result in these massive events, but extraterrestrial ones as well. 

So how are current events remotely related to this? Well, chances are, you’ve heard something called climate change, in which the Earth warms because of greenhouse gases, and living things are dying because their homes are getting destroyed by the warming temperatures (among other things, such as humans). You see, most of the previously mentioned mass extinction events have been related to global warming, causing many animals to lose their homes and food because it was so hot. The key difference between previous cases and the current issue is the rate of heating. The previous cases (that had global warming) had been gradual, but still dangerously high rates of increase, however, the world in the next century has been predicted to warm 2 - 6 degrees Celsius, compared to the warming of 5 degrees celsius the last 5,000 years. This rapid increase in temperature has resulted in the rise of sea levels, increase in global temperature, and extreme weather events, all due to humans releasing copious amounts of CO2 from the burning of fossil fuels. 

We know that a massive amount of species are dying, but can we claim that this is a mass extinction-level event? The answer to this question may not be what you think, in fact, the extinction event could have been happening long before humans even discovered fossil fuels. A study done by Brown University calculated that the normal rate of extinction before humanity was 0.1 extinctions per 1 million species per year. Now it is at 100 extinctions per 1 million species per year, and they expect up to 10,000 (per the previous estimates) in the future. Adding on, the IUCN predicts that 99.9% of critically endangered species and 67% of endangered species to be lost in the next 100 years, literally adding on to the list. Some may argue, “well what if some specific species die, I’m sure the ecosystems will be just fine, who cares about biodiversity, the less, the better!” Biodiversity is essential for many forms of agriculture, such as the fact that 75% of all food crops rely on pollination from a variety of animals, biodiversity ensures natural sustainability and stability for ecosystems, meaning that if we unbalance those ecosystems that we rely on for water, soil fertility, etc. will cease to exist and we are left without essentials that people in the Amazon to New York City rely on every day. 

A study from 2015 comparing specific vertebrate species extinction rate compared to the background rate clearly shows the rise in the extinctions of vertebrates across a 600-year timespan. The graphs show the percentage of the number of species going extinct in different animal groups. Clearly, both the conservative and highly conservative estimates point to the fact that extinction rates have only increased since the introduction of industrialization and humanity growing in size. While all this evidence clearly points to the fact that we are heading towards a 6th mass extinction, one can argue it is already here because of the fact that this is the beginning of the massive increase in the rate of extinctions.

With all this said, it may seem like all hope is lost for these endangered species and the biomes they live in and frankly, there is not much one can do to prevent such from happening. However, there are still measures you can take such as using electric cars (or biking, walking, etc.), recycling, eat foods that have less impact on the environment. Pessimistically speaking, following these procedures won’t even put a scratch, let alone touch on our emissions, but the small steps are better than nothing, and I highly suggest you donate to non-profit organizations such as Ocean Cleanup, the Conservation Fund, or anywhere else one deems fit that will dent the impact of our footprint. I hope this article may have shined a little more light on the extinctions that continue to occur and the enormity of the situation at hand. The journey to the future was never meant to be easy, so maybe this is just another test humanity as a whole needs to pass in order to be able to expand to the stars, or maybe not.

Sources: 

UC Museum of Paleontology. “Mass Extinctions - Understanding Evolution.” Understanding Evolution -Your One-Stop Source for Information on Evolution, UC Berkeley, 18 Nov. 2021,              https://evolution.berkeley.edu/mass-extinctions/. 

NASA. “Global Warming.” NASA, NASA, https://earthobservatory.nasa.gov/features/GlobalWarming/page3.php. 

September 2, 2014 Media contact: David Orenstein   401-863-1862. “Extinctions during Human Era Worse than Thought.” Extinctions during Human Era Worse than Thought | News from Brown, 2 Sept.

2014, https://news.brown.edu/articles/2014/09/extinctions. 

Ceballos, Gerardo et al. “Accelerated Modern Human–Induced Species Losses: Entering the Sixth Mass Extinction”. Science advances 1.5 (2015): n. pag. Web.

National Geographic Society. “Mass Extinctions.” National Geographic Society, 30 July 2019, https://www.nationalgeographic.org/media/mass-extinctions/#mass-extinction. 

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