Friday, September 30, 2016

Sixth Extinction Crisis

                Comments due by October 7, 2016

It’s frightening but true: Our planet is now in the midst of its sixth mass extinction of plants and animals — the sixth wave of extinctions in the past half-billion years. We’re currently experiencing the worst spate of species die-offs since the loss of the dinosaurs 65 million years ago. Although extinction is a natural phenomenon, it occurs at a natural “background” rate of about one to five species per year. Scientists estimate we’re now losing species at 1,000 to 10,000 times the background rate, with literally dozens going extinct every day [1]. It could be a scary future indeed, with as many as 30 to 50 percent of all species possibly heading toward extinction by mid-century [2].

Unlike past mass extinctions, caused by events like asteroid strikes, volcanic eruptions, and natural climate shifts, the current crisis is almost entirely caused by us — humans. In fact, 99 percent of currently threatened species are at risk from human activities, primarily those driving habitat loss, introduction of exotic species, and global warming [3]. Because the rate of change in our biosphere is increasing, and because every species’ extinction potentially leads to the extinction of others bound to that species in a complex ecological web, numbers of extinctions are likely to snowball in the coming decades as ecosystems unravel. 

Species diversity ensures ecosystem resilience, giving ecological communities the scope they need to withstand stress. Thus while conservationists often justifiably focus their efforts on species-rich ecosystems like rainforests and coral reefs — which have a lot to lose — a comprehensive strategy for saving biodiversity must also include habitat types with fewer species, like grasslands, tundra, and polar seas — for which any loss could be irreversibly devastating. And while much concern over extinction focuses on globally lost species, most of biodiversity’s benefits take place at a local level, and conserving local populations is the only way to ensure genetic diversity critical for a species’ long-term survival.

In the past 500 years, we know of approximately 1,000 species that have gone extinct, from the woodland bison of West Virginia and Arizona’s Merriam’s elk to the Rocky Mountain grasshopper, passenger pigeon and Puerto Rico’s Culebra parrot — but this doesn’t account for thousands of species that disappeared before scientists had a chance to describe them [4]. Nobody really knows how many species are in danger of becoming extinct. Noted conservation scientist David Wilcove estimates that there are 14,000 to 35,000 endangered species in the United States, which is 7 to 18 percent of U.S. flora and fauna. The IUCN has assessed roughly 3 percent of described species and identified 16,928 species worldwide as being threatened with extinction, or roughly 38 percent of those assessed. In its latest four-year endangered species assessment, the IUCN reports that the world won’t meet a goal of reversing the extinction trend toward species depletion by 2010 [5].

What’s clear is that many thousands of species are at risk of disappearing forever in the coming decades.

No group of animals has a higher rate of endangerment than amphibians. Scientists estimate that a third or more of all the roughly 6,300 known species of amphibians are at risk of extinction [6]. The current amphibian extinction rate may range from 25,039 to 45,474 times the background extinction rate [7].

Frogs, toads, and salamanders are disappearing because of habitat loss, water and air pollution, climate change, ultraviolet light exposure, introduced exotic species, and disease. Because of their sensitivity to environmental changes, vanishing amphibians should be viewed as the canary in the global coal mine, signaling subtle yet radical ecosystem changes that could ultimately claim many other species, including humans.


Birds occur in nearly every habitat on the planet and are often the most visible and familiar wildlife to people across the globe. As such, they provide an important bellwether for tracking changes to the biosphere. Declining bird populations across most to all habitats confirm that profound changes are occurring on our planet in response to human activities. 

A 2009 report on the state of birds in the United States found that 251 (31 percent) of the 800 species in the country are of conservation concern [8]. Globally, BirdLife International estimates that 12 percent of known 9,865 bird species are now considered threatened, with 192 species, or 2 percent, facing  an “extremely high risk” of extinction in the wild — two more species than in 2008. Habitat loss and degradation have caused most of the bird declines, but the impacts of invasive species and capture by collectors play a big role, too.


Increasing demand for water, the damming of rivers throughout the world, the dumping and accumulation of various pollutants, and invasive species make aquatic ecosystems some of the most threatened on the planet; thus, it’s not surprising that there are many fish species that are endangered in both freshwater and marine habitats. 

The American Fisheries Society identified 700 species of freshwater or anadromous fish in North America as being imperiled, amounting to 39 percent of all such fish on the continent [9]. In North American marine waters, at least 82 fish species are imperiled. Across the globe, 1,851 species of fish —  21 percent of all fish species evaluated —  were deemed at risk of extinction by the IUCN in 2010, including more than a third of sharks and rays. 


Invertebrates, from butterflies to mollusks to earthworms to corals, are vastly diverse — and though no one knows just how many invertebrate species exist, they’re estimated to account for about 97 percent of the total species of animals on Earth [10]. Of the 1.3 million known invertebrate species, the IUCN has evaluated about 9,526 species, with about 30 percent of the species evaluated at risk of extinction. Freshwater invertebrates are severely threatened by water pollution, groundwater withdrawal, and water projects, while a large number of invertebrates of notable scientific significance have become either endangered or extinct due to deforestation, especially because of the rapid destruction of tropical rainforests. In the ocean, reef-building corals are declining at an alarming rate: 2008’s first-ever comprehensive global assessment of these animals revealed that a third of reef-building corals are threatened.

Perhaps one of the most striking elements of the present extinction crisis is the fact that the majority of our closest relatives — the primates — are severely endangered. About 90 percent of primates — the group that contains monkeys, lemurs, lorids, galagos, tarsiers, and apes (as well as humans) — live in tropical forests, which are fast disappearing. The IUCN estimates that almost 50 percent of the world’s primate species are at risk of extinction. Overall, the IUCN estimates that half the globe’s 5,491 known mammals are declining in population and a fifth are clearly at risk of disappearing forever with no less than 1,131 mammals across the globe classified as endangered, threatened, or vulnerable. In addition to primates, marine mammals — including several species of whales, dolphins, and porpoises — are among those mammals slipping most quickly toward extinction. 

Through photosynthesis, plants provide the oxygen we breathe and the food we eat and are thus the foundation of most life on Earth. They’re also the source of a majority of medicines in use today. Of the more than 300,000 known species of plants, the IUCN has evaluated only 12,914 species, finding that about 68 percent of evaluated plant species are threatened with extinction.

Unlike animals, plants can’t readily move as their habitat is destroyed, making them particularly vulnerable to extinction. Indeed, one study found that habitat destruction leads to an “extinction debt,” whereby plants that appear dominant will disappear over time because they aren’t able to disperse to new habitat patches [11]. Global warming is likely to substantially exacerbate this problem. Already, scientists say, warming temperatures are causing quick and dramatic changes in the range and distribution of plants around the world. With plants making up the backbone of ecosystems and the base of the food chain, that’s very bad news for all species, which depend on plants for food, shelter, and survival.


Globally, 21 percent of the total evaluated reptiles in the world are deemed endangered or vulnerable to extinction by the IUCN — 594 species — while in the United States, 32 reptile species are at risk, about 9 percent of the total. Island reptile species have been dealt the hardest blow, with at least 28 island reptiles having died out since 1600. But scientists say that island-style extinctions are creeping onto the mainlands because human activities fragment continental habitats, creating “virtual islands” as they isolate species from one another, preventing interbreeding and hindering populations’ health. The main threats to reptiles are habitat destruction and the invasion of nonnative species, which prey on reptiles and compete with them for habitat and food.


  1. The ‘snowball’ effect noted in the article is one that is truly troubling, as well as something I’d never considered. Of course, we know that species are interdependently woven into complex ecosystems, but the idea that the elimination of one species will lead to the eventual unraveling of the entire system is truly frightening.

    The numbers that outline figures with regard to specific animal groups are also troubling ones. I wonder, though, is there anything that can be done? Is this cycle completely inevitable? I imagine trouble within various ecosystems will causes issues that we may not even understand yet. It’s frightening to think that we may only be able to marginal stop this progression, if we are even able to accomplish that.

    It seems that it would be of particular importance to stem the tide of plant destruction, considering all that they appear to provide for human beings. Adding to their importance is that they likely support, in some way, almost every ecosystem imaginable. I would hope that some progress on this front would be possible given appropriate efforts relating to climate change.

  2. The alarming rates of wildlife extinction are a clear indicator that human activity is a danger to society. We most often do not consider every action we take throughout the day and its potential environmental impact. As I sit in Starbucks writing this, I see about 20 plastic and paper cups that will likely be disposed of in a landfill, releasing carbons and other chemicals into the ground, groundwater, and atmosphere. It is simply irresponsible to continue polluting the Earth without any regard for the long term effects. People may say, oh well the Puerto Rican Culebra parrot isn't an aspect of my life, so who cares. Imagine trying to bake cookies, and flour as a resource has been depleted (clearly can't make the cookies). The food chain is much more complex but works in a similar manner, every species that faces extinction increases the likelihood of another species in the same danger. When it reaches the top of the food chain, maybe we will start to care. On individual levels, it is important to recycle and dispose of waste repsonsibly, make use of public transportation (further boosting the economy), etc. But the real offenders are big business. Factories with thick black smog overhead, emptying into the atmosphere. Our current emission standards that companies follow are not strict enough. These simply state how much a firm can pollute, and if expanding business means increasing pollution, then a firm will only produce at its maximum allowable emission output, not allowing economic growth. I can not say how we will fix this, whether it be subsidiaries and incentives for firms to adopt green technology or providing greater aid to engineers and innovators of green tech. It is mind boggling to think that people are either 1) unaware of the adverse affects we all have on the Earth or 2)are aware of the adverse affects and do not see it urgent reform immediately.

  3. Reading this is a wake up call to the harm the human race is doing to not only the planet, but the creatures within. I am a very proactive member of society when it comes to animal welfare. I am aware of the ways different species suffer regarding the meat industry and various fossil fuels and pollution, but seeing each section of animals and plants described in detail made it even more clear. If more people would take action against things like pollution and fossil fuels, we could work to save the animals as well as natural resources.

    We may not be able to completely change every way we burn fuels or deal with waste, but we can sufficiently reduce the negative impacts we are imposing on the planet by changing the amount of energy we use, the amount of pollutants we release into the air, and the amount of fossil fuels we burn. Taking steps to do this, and reducing these things (even just by small amounts), will help in preserving the wildlife and the planet, as well as work to prevent global warming.

  4. This blog brings up many valid points about how interconnected all species on the planet are, and the devastating effects that could happen if they were to go extinct. As stated in the article, species diversity ensures ecosystem resilience. This is due to the fact that each organism has a unique role to fill in the ecosystem. When one species is unable to fill their unique role, it throws off the balance of the entire ecosystem. I was alarmed to hear that 30 to 50 percent of all species could possibly be heading towards extinction by mid century. That is a huge number and really opened up my eyes to how big this problem is. All these negative impacts are brought on by human acitivty. We must reduce our energy use, cut back on habitat destruction, and work to become more sustainable to ensure a healthier planet.

  5. This article is a huge shock. To see the damage we are doing in regard to extinction, quantified appears devastating. I actually did not know that extinction was a natural occurrence. At least not as regular as it is. And I also did not know there were five major extinctions before our current crisis. The author states that we are losing species from 1,000 to 10,000 times faster than the normal “background” rate. What didn’t surprise me at all was the fact that 99% of current species extinction is due to human activity. I would imagine that habitat loss is among the top causes. Living in the suburbs of Northern Jersey, I’ve noticed a rapid increase in road kill parallel with the real estate development of our wooded areas. But, with the rise in human’s carrying capacity falls that of other species. It is scary to read that because of the extinction of one species, a domino effect will occur, killing off other species. The more biodiverse an ecosystem is, the more resilient it will be from “stress.” One thing I found to be new to me was the importance of less biodiverse ecosystems. The author stressed that they are just as crucial as more diverse regions. I also thought it was inconvenient that with the rise in our population booming and the rapid extinction of animals came the uneasy fact that scientists didn’t have enough time to document and identify the hundreds to thousands of extinct species in the past few decades.

  6. I feel like every article is a completely shock due to the problems that we, the humans, have caused to the environment. But this article is alarming. It is incredible how long it take for new species to form and for us to discover them and how fast it is for us to destroy their environment, their shelter or even their food and lead them to extinction. It is frightening to see all of those numbers and how, if we keep this pollution rate, they are going to decrease drastically. Everyday we hear news about how the animals are disappearing and how the pollution we cause makes more steps forward their extinction, but instead of putting a remedy, we just keep pollution the waters, polluting the air and destroying the ecosystems. It looks like we care about wildlife and animals but we really do not. We just keep haunting more, fishing even more, killing more animals etc, just to get more profit, make more money and destroy our planet's fauna.
    A thing that drives me even more crazier, is the fact that we also keep destroying ecosystems, cutting down trees, destroying entire forests, etc. without realizing that with no trees and plants, there is no photosynthesis, which means that there is no oxygen created, therefore the polluted air cannot be "purified", which is something that we, the humans need to live. We are not realizing that we are not only leading to animal extinction, but also leading to our own extinction.

  7. I’ve been hearing a lot about this global issue for many years already, and reading this post only reminds me more that we need to act now and do something about this dilemma. I do believe that if things keep going the way it’s going now, at this rate we won’t have a planet to live on. This environment is slowly decaying due to mass production of population and waste. If we don’t change our way of living, one day we won’t have any more natural resources, our plants will become extinct, other living organisms will become extinct, and finally the human species will become extinct. Thus the last entity that will become extinct is planet earth. One aspect of this article that completely shocked me was the information about the different species and life forms that are currently declining and will soon cease to exist. I was alarmed to hear that by mid century, 30 to 50 percent of all species could possibly be heading towards extinction. It really opens my eyes to the how grave this problem has become over the years. We need to come together as a community and help preserve this earth because if we don’t, then might as well call it quits on life; because there wont be an earth to live on at this rate.

  8. I always understood that extinction is a natural process and has occurred many times in the past. However, I believe our actions towards the environment are rapidly speeding up this process. After reading about the sixth extinction crisis, I can see how badly we are affecting the animals and plants in our ecosystem. These statistics are scary to see because every animal and species lends a hand in maintaining our ecosystem. The more animals become extinct the greater the impact on our planet and on our lives. Not only are animals in danger but very important invertebrates such as coral reefs, are at risk of extinction. Coral reefs maintain large ecosystems for a variety of aquatic life as well as help clean the ocean’s water. Not only this but overfishing, as well as pollution and exposure to diseases, has caused fish populations to dwindle. There are many different species’ affected by the changes in the environment that we caused but people continue to argue that we shouldn’t do anything to revive endangered species. However, because we’re losing species at 1,000 to 10,000 times the normal rate we have an obligation to change. People continue to deny the reality of climate change because they want to continue in their ways, but this will only hurt the animals and plants around us and then, ourselves.

  9. It is obvious that biological diversity plays an important role in ecosystem. As the article said; "Species diversity ensures ecosystem resilience, giving ecological communities the scope they need to withstand stress." Because of people's activities, a lot of animals lose their habitats. This is a reason that animals are at risk of extinction. In addition, people's activities pollute the water and air, which means that animals' health are threaten by people's activities. Furthermore, people's activities will cause the extinction of plants. Following the extinction of plants, animals will be at risk of extinction, because animals depend on plants for food, shelter, and survival. With the decline of biological diversity, ecosystem will have more stresses. In this way, people's life will be threaten, because people live in this ecosystem. Thus, we should protect animals, protect biological diversity, protect ecosystem.

  10. The complete loss of an entire species is a hard fact to come to terms with. While I may have differing opinions I'd like to challenge readers to consider some contrasting ideas. If humanity is thriving as it is and growing ever larger and the area we are living in is not increasing, something has to give. There is little in our history books that shows a dominating race as much as we are right now. It is a matter of fact that with our nature of abusing resources, misallocating resources from caring for our planet and the ever shrinking amount of land and resources native animals are provided that species will go extinct in increasing rates.

    What is important to keep in mind is that this is all very exponential. As we are beginning to notice the effects humanity have wrought upon Earth we must keep in mind that these results will only happen more and more often. By the time our generations are old we will have a much better perception of the entire matter I'm describing.

  11. This article is extremely informative and one of the most well written pieces on the topic i have read, granted I haven't read much. The fact that I don't know much on the topic is alarming since one can safely assume that the majority of people aren't aware of such significant changes that are occurring.

    People are generally aware of the issue but never stop to think what the actual results and long-term effects are. The deforestation across the world and destroying of habitats are driven by corporate interest seeking short-term gains. With a belief that those places arent need since we are building a fabricated world We are approaching an era where are actions cannot be undone and resolved. These statistics and research need to be more public to reach the common man to educate on what is happening. If the leaders of the world do not come together in conjunction with UN to come up with a strategic plan. We must not isolate ourselves as countries but come together for the greater good.

  12. With all the information available on wildlife it is still amazing to me how the public is not making a great effort to address these issues. By the time we, as a society, decides to tackle these issues and, dedicate the right amount of time and resources, human beings will be feeling the effects of mass extinction. The extinction of marine life is particularly scary to me. 70% of the world consists of water and water is crucial in sustaining our life as humans. We are continuing to grow as a species right now, but there are already concerns about feeding the world. What are we going to do when mass extiniction comes into fruition? Theres really no way to tell the magnitude of the repercussions that may come our way if we do not seriously address these issues.

  13. The planet is currently facing it’s sixth wave of extinctions in the past half-billion years, with dozens of species dying every day. I believe many humans are looking for ways to reduce the damage, especially by focusing on species-rich ecosystems such as rainforests and coral reefs. Humans can reduce their activity in areas that lead the destruction of these ecosystems. I understand a big reason why species are at risk because of the climate change I do feel there are places we can actively work, such as lessening pollution, deforestation, and the use of pesticides.
    As a young kid first learning about “extinction” it really traumatized me. I would google pictures of extinct animals, or read articles about animals added to the endangered list. I also remember supporting WWF at a young age, buying t-shirts, and even the build-a-bear. It’s heartbreaking to know that humans cause such destruction, and we do it so carelessly. Along with the death of so many species of animals, there is also the devastating loss of over 300,000 plant species. Plants are essential for providing energy for the entire ecosystem, they also provide us with oxygen, nutrients, and even medication.
    One species in particular that many are worried about is already too close to becoming extinct are the bees. Since bees are responsible for pollinating one third of the world’s food supply, the alarming rate that they’re dying should be a wake up call to all. Even though bees are so vital to our existence, most states still use pesticides (neonicotinoids) that have been linked to significant bee declines. As of now, only the state of Maryland has a piece of legislation that bans the use of neonicotinoids, so they continue to be used on many crops all over the United States. If more people do not get involved, become knowledgeable, and support legislation (or by supporting and voting for the candidates who support the legislation), our future is headed towards the scary possibility of having 30 – 50% of all specifies extinct by mid-century.

  14. It was very concerning to read about this topic. I have worked on a project for a class I took, Nature and Connections, and our topic was the effect of the extinction of one type of specie on the ecosystem. Our job was to look for and pick one animal and see the importance of it in the interconnected ecosystem. I chose research about elephant and write about the important role they play in the ecosystem and on the environment. With the research I made, I could clearly see the impact of just one specie on the environment as a whole. As the article states the decreasing number of the specie was caused by humans. The main reason why African and Asian elephants dying was because hunting for their tusks or ruining their habitat with the increasing number of human population. The whole ecosystem is greatly connected to each other. Each specie naturally supports each other' one way or another and the extinction of even a few can have tremendous effects on our entire environment. Imagining the extinction of 30 to 50% of different species being extinct by mid century is definitely alarming. This topic again ties into how we treat our environment. "Risky human activity", not only causes the extinction of species but it also ruins our own environment. It frustrates me to think about how incautious humans are. There are people who still don't accept or understand the significance of climate change.

  15. We are at a point where the extinction level of species is reaching extremes, such as the extinction of dinosaurs. This is an unimaginable notion. Amphibians having the highest rate of all, all species are under the danger of extinction due to human activity. The most important thing to understand here is the "snowball effect".

    In the text, "snowball effect" is used to describe the effect of each specie's extinction on another. The entire ecosystem is connected to each other in a very complex matter. It can be seen as a spider web. With the shocking numbers of endangered species, (14,000- 35,000, only in the united states alone) we can tell that we really are facing a problem. When we look at some of the reasons why certain type of animals are disappearing, we can see that environmental change effects most of them. Other elements such as capture and hunting play a big role too. For example; frogs decreasing in number due to habitat loss and air/water pollution, birds due to capture, fish due to damming of waters,and whales due to hunting, the cause of the problem is in front of us because it is us. Many species have sensitivity towards environment change. Environment change is impossible to avoid with this rate of climate change we experience. Unfortunately, the climate change doesn't seem to be getting better. Therefore, it is not false to assume that the estimated extinction of all species seem to be on the way.