Mass extinction in our lifetime
by Rebecca Twinney
Sixty-six million years ago: Dinosaurs rule the planet. They range from the size of chickens to that of cargo ships, but they are all about to share a similar fate. At 45,000 miles per hour, a massive chunk of cosmic rock somersaults toward Earth. While the sauropods sleep, a meteor shower streaks the sky orange. Combusting in the Earth’s atmosphere, these asteroid fragments only warn of what is to come.
By the time the meteor reaches the earth, its explosive force exceeds that of all nuclear weapons ever made, combined. The friction of the atmosphere sets the cosmic cannonball on fire and sends burning boulders into the sky. The dinosaurs not broiled alive by the impact soon find themselves caught in a shower of flames. Brighter than a million suns, the blistering fireball is the last image thousands of creatures will see. Within the next 50 years, all non-avian dinosaurs and over half of their contemporary species will go extinct.
Today, when we think of extinctions, we picture this scene. We imagine scorched valleys strewn with the carcasses of T. Rex and Stegosauruses. We envision the last surviving triceratops succumbing to starvation. But we fail to see the far quieter extinctions that exist in our own lifetimes.
Last week, a Facebook post presented a picture of two West African black rhinoceroses overlaid with the word “Extinct.” Social media users shared outraged comments about the great tragedy. They were horrified to find out that they would never again see a West African black rhino anywhere on Earth. But the reality is that the subspecies actually went extinct in 2011. It has been extinct for years, but many people are only just finding out. And while there’s nothing wrong with mourning the misfortune anew, it hardly felt like a reminder. It was a wakeup call.
Between 1960 and 1995, the West African black rhino population decreased by 98 percent. A quick image search reveals the gruesome reality of this statistic. Photos of 3000-pound rhinos, lying dead with their faces hacked to pieces, illustrate the consequences of ruthless poaching. The World Wildlife Fund (WWF) estimates that in order to supply horns to Chinese and Middle Eastern markets, at least two rhinos were killed every day. By 1997, only ten members of the subspecies remained. Today, there are none.
One of evolution’s oldest groups of mammals at 20 million years, rhinos are virtually living fossils. They are sentient reminders of life’s astounding ability to regenerate after widespread extermination. However, while we may assume that the Earth will once again revive itself after another round of extinctions, there is a fundamental difference between past and future events. An asteroid caused the fifth mass extinction. According to journalist Elizabeth Kolbert, humans are causing the sixth. And just as Kolbert mentioned in her recent visit to Colorado College’s campus, it’s happening much faster than we realize.
National Geographic and WWF estimate that between 200 and 2,000 extinctions occur every year. In the past decade, the Earth lost the golden toad, the black-faced honeycreeper, the monk seal and the baiji dolphin. And this list is nowhere near complete. According to the Center for Biological Diversity, over a third of all amphibian and invertebrate species are at risk of extinction. Almost a fourth of fish species, a fifth of mammal species and an eighth of bird species are also threatened by human activities.
Out of the many human impacts, deforestation and habitat loss play the most significant roles in current extinction rates. In addition to agriculture and livestock rearing, urban sprawl, infrastructure, and manufacturing largely contribute to the deforestation of the world’s forests. According to the World Preservation Foundation, one-and-a-half acres of forest disappears every second. That amounts to the loss of 20 football fields every minute. If this rate continues, rainforests will cease to exist on earth within the next 100 years.
Along with the loss of carbon dioxide sinks, deforestation also reduces available habitat for thousands of species. In fact, within the next 25 years, conservationists expect up to 28,000 species to go extinct due to habitat loss. Of these species, humans’ closest relatives are disproportionately affected. According to the Center for Biological Diversity, over half of all primate species are endangered, compared to a fifth of all mammal species. Despite their close evolutionary link to humans, orangutans are one of the most critically endangered primates. The Orangutan Project states that although only 6,000 orangutans exist in the wild, almost 1,000 are killed each year.
Overharvesting also plays a major role in species depletion and overfishing threatens more than a third of all sharks and rays. Likewise, despite international and domestic laws, poachers kill over 5,000 leopards each year. Even closer to home, American and European trophy hunters kill about 600 lions per year. Averaging five lions a day while accounting for native poaching, these depletion rates may decimate the king of the jungle within the next few centuries.
In a potent example of overharvesting, the population of the iconic passenger pigeon decreased from over three billion individuals to zero in a single lifetime. According to the Huffington Post, passenger pigeons once constituted between one fourth and one half of the United States’ total number of birds. However, as hunting and deforestation increased into the 19th century, the species declined substantially. In 1914, Martha, the world’s last passenger pigeon, passed away, marking the complete disappearance of a once-plentiful species.
Sadly, Martha was not the only animal to witness the extinction of her species. The journal “Nature” even coined a term for an individual that represents the last of its kind: an endling. Celia, the last Pyrenean ibex and Benjamin, the last Tazmanian tiger, watched their species succumb to hunting pressures. The aptly named Lonesome George, the last Pinta Island tortoise, also bore the stain of a crisis recognized too little, too late.
Like the West African black rhinoceros, Asian and African rhinoceros subspecies suffer significantly from poaching. As the fifth most profitable illicit trade in the world, the market for animal parts is only growing. And as a result, the Javan rhino, Sumatran rhino, and northern white rhino are currently teetering on the brink of extinction. With only one surviving male, the northern white rhino’s disappearance is nearly assured. In a last-ditch effort, four rangers with AK-47s guard the lone male around the clock. The rhino’s horn has been removed for its protection, and the rangers have orders to shoot potential poachers on sight. The image paints a bleak picture of conservation.
While humans have seemingly failed these subspecies, the story is not all doom and gloom. In 1900, the southern white rhinoceros was the most endangered rhino species. With fewer than 20 individuals remaining, the species’ future looked bleak. Now the most populous rhino species on Earth, southern white rhinos illustrate the importance of understanding the market that fuels their demise. According to the Property and Environmental Research Center, by 2010, their numbers rose to over 20,000. By implementing a policy that allowed the private ownership of southern white rhinos, South Africa privatized the species. Because the horns were worth thousands of dollars, the policy incentivized breeding rhinos, rather than killing them. By increasing the market value of live rhinos, this method institutionalized the real costs of killing wildlife.
For conservation initiatives like this one, the stakes are even higher than may appear at first glance. As keystone species, rhinos enable other animals to survive in African grasslands. A recent study in the “Journal of Ecology” found that rhinos often forgo the more nutritious grasses for the more plentiful ones. In doing so, the species increases plant diversity, augmenting the proportion of nutritious plants by up to 80 percent in a given area. In this way, they facilitate the existence of other grazing animals like zebras, gazelles and antelopes. With the disappearance of rhinos from Kruger National Park in South Africa, grasslands saw the decline of vital plant communities, endangering countless other species.
Unfortunately, the public often fails to see this ecological chain of events before it’s too late. While the West African black rhinoceros may only represent a single extinction, its disappearance will trigger a cascade of changes. Just like the scorching fragments of asteroid, every extinction event elicits ripple effects. The ripple effects of the dinosaurs’ demise subsequently allowed the rise of mammals. By opening ecological spaces for other forms of life, the mass destruction actually facilitated the evolution of human beings. The fifth major extinction led to our creation, but the sixth will be our demise.