Human Impact on the Environment

Today there was an article in the local newspaper here in Charleston, SC (The Post and Courier) about the constantly changing (dynamic) behavior of the natural world and humans impact on it (link to the article here).  It does a really good job of discussing the way the local environment has changed over the past 75 years and gives examples of how we as humans have played our part  (good or bad) in that change.  It is a really well written article and brings up a lot of good points about how humans are changing the landscape of the planet and how it is affecting the natural world.  The article even did this without a mention of the very controversial topic of “climate change.”

This is a great topic that I want to discuss.  I have just finished reading a book called “The Sixth Extinction: An Unnatural History” by Elizabeth Kolbert.  This book gives a great overall explanation of the current extinction rate, which is estimated at around 1,000 – 10,000 times higher than background extinction rate, and gives great examples of organisms that have gone extinct in human history.  This “Sixth Extinction” event, which most scientist agree we are in the middle of right now, can be nearly directly attributed to humans.  99% of all threatened or endangered species are currently at risk due to human activities, mainly habitat loss or interactions with invasive species.  Scientist have started to notice that historically when humans radiate into a new area, extinction rates go up (the biggest example is that when humans radiated into North America for the first time approximately 13,000 years ago, it took very little time for all the mega-fauna to become extinct in North America).  While there are many factors that affect extinction rate we know that today humans have taken over nearly every landmass on the planet and wherever humans go, a rise in extinction rates follow.

Here are some stats on how much of an impact that humans currently have on the environment: 1/3-1/2 of all the land surface on the planet has been transformed by humans, most major rivers have been dammed or diverted, fertilizer plants produce more nitrogen than can be naturally fixed, fisheries remove more than 1/3 of the primary production of oceans each year, and humans use more than 1/2 of the freshwater runoff.  These are drastic numbers and are expected to go up as population grows and we develop more land.  While we are on stats, here are some stats of the current estimates of endangered species by class: 1/3 of all reef building corals, 1/3 of all freshwater mollusks, 1/3 of all sharks and rays, 1/4 of all mammals, 1/5 of all reptiles, and 1/6 of all birds (this doesn’t count the many species that are showing drastic declines in their ranges all over the planet).  These species are endangered to the point where we could loose many thousands of species in the coming decades, and the only thing to blame for it would be humans undying need to bend the environment to their will.  No other organism in Earths history has ever had an impact on the planet like humans and it is up to us to clean up our mess.

This by far isn’t all the information in this book.  It is a good read and tells a lot of success stories as well, such as the Bald Eagle.  It also discusses other ways in which humans are changing the environment and does a great job of explaining the effects of these changes.  I also enjoyed that it didn’t harp on climate change as much as a lot of other books, even though it does talk about it, it is not the overall theme of the book.  While I do like reading about climate change, this book points out that there are many other, and I argue just as important, ecological problems that we humans need to address that sometimes get drowned out by the climate change babble.   It is a very fascinating and eye opening book that shows just how powerful and invasive of a species we humans really are.  I recommend it to anyone who loves to read about the environment.

I will leave you with a quote I came across:

“The end of the human race will be that it will eventually die of civilization”  -Ralph Waldo Emmerson


Kolbert, Elizabeth. 2014. The Sixth Extinction: an Unnatural History. 1st ed. Henry Holt & Co.

also if you are interested in reading more about this topic click here


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