Historically, there have been five mass extinctions, which are explored in great detail in Cosmos Magazine. The Ordovician mass extinction, thought to be caused by an ice age, occurred 444 million years ago when life on earth was primarily marine, and resulted in the loss of about 86 percent of all species over one million years. It was followed by the Devonian mass extinction, where three quarters of the species on earth perished, likely due to changes in ocean conditions caused by the emergence of more evolved land plants. Next came the Permian extinction, also know as the “great dying” because it is considered the worst mass extinction by far, killing off about 96 percent of all species as a result of a series of remarkably severe natural catastrophes. Finally, the most recent two extinctions were the Triassic and Cretaceous which occurred 200 million and 66 years ago, consecutively. While no cause has been identified for the Triassic mass extinction, the Cretaceous extinction is believed to be caused by the coupled effects of volcanic activity, climate change, and an asteroid collision with Earth.
Many scientists believe that we are now moving towards a sixth mass extinction; however, this differs from the previous ones in that it is manmade. The Center for Biological Diversity describes the rate of species extinction to be about 1,000 to 10,000 times higher than it would be naturally. The center also states that as many as 30 to 50 percent of all species may be extinct by the middle of the 21st century, a terrifying possibility in the very near future. This has the potential to reduce significantly the biodiversity that was once present on earth.
The three largest factors in this high rate of extinction have been the introduction of exotic species to new
Photo credit: https://www.weforum.org/agenda/2016/01/sixth-mass-extinction-is-upon-us-and-its-our-fault/
ecological communities, habitat loss, and global warming. Introducing new species into communities can disrupt the balance and the dynamics between predator and prey. Often introduced species become invasive species, which reproduce and spread quickly and negatively impact other species. The National Wildlife Federation states that about 42 percent of all threatened or endangered species are in danger at least partially because of invasive species. Habitat loss is likely the largest factor in the extinction of such a massive amount of species. Deforestation has been a major contributor to this issue, particularly as forests have been cut down in order to make more room for farming to be able to sustain a growing population. Virtually every habitat has suffered from this as new neighborhoods, malls, and businesses replace them. Finally, global warming has played a factor in the extinction of many species, as global warming has caused significant climate change that has altered the environments that species lived in. Those that are unable to adapt to these changes are dying off.
Another major issue with the progressive loss of different species is that many species are dependent on the existence of other species. As a result, when one species in an ecological community goes extinct, many other species in that environment can be strongly impacted, and may soon become endangered or extinct as well. This has already started to create a coupling effect that could escalate significantly in the next few decades and cause the foundation of many ecosystems to fall apart.
Beyond the devastating implications of the loss of so many species, these extinctions will also have direct impacts on people’s way of life, and in some cases already have, according to an article by Milton Kazmeyer. For instance, Native Americans once hunted Bison for a living, but after the number of bison started to decline, they were forced to get support from the American government to survive. There are also numerous potential problems for the future. People rely on bees to pollinate plants, many of which are used for food; however, bees have already begun to dwindle in number. On a similar note loss of diversity could have an impact on disease and medicine in the future. Many species act as buffers between us and potentially dangerous diseases. Likewise, many species have provided remarkable cures for various ailments; it is highly possible that some of these cures could be extinct before we can find them.
In order to avoid catastrophe, our society will have to make some major changes. To begin with, we need to stop burning fossil fuels to try to slow down Global Warming. On a similar note, we have to protect habitats for the many diverse species that occupy earth, which means both cutting down pollution as well as slowing down our replacement of ecosystems with buildings and farmland. Finally, we need to get human overpopulation under control. It is really essential that people make it more of a priority to get these issues under control, because the planet cannot sustain the kind of abuse that mankind is doing.
This issue worries me greatly. Especially considering the kind of environmental policy that’s going to be enacted over the next four years. I worry that people aren’t going to truly take this issue seriously until it is too late. I feel like there is going to be a point past which the problem is irreversible and I just hope that mankind comes to recognize the problem before we pass that point. My blog post this week focuses on a similar topic, but focuses specifically on using renewable energy as a solution for the carbon emissions caused by fossil fuels. I hope that industry starts to take advantage of these alternatives now before we really have a catastrophe like a mass extinction.
I can definitely see how this is possible, especially because it’s man-made. I feel like people are very unaware that this could actually happen. We have done so much by man instead of by nature that it will be difficult to decrease and ultimately spiral downward.