By David L. Brown
The evidence continues to mount that the Earth is entering into a mass extinction event that could dwarf even the one that ended the age of dinosaurs. One of the most ominous clues is the widespread die-off of amphibians.
Why frogs, toads and salamanders should be disappearing is puzzling. After all, amphibians have been around for 250 million years and survived the extinction event 65 million years ago when the dinosaurs bit the dust. There seems to be no single answer, but the suspicion is that it all has to do with the changes Man has brought to the planet.
Frogs may be the “canary in the mine” for many other species, which already have either disappeared or are in danger of doing so. According to an article this morning on the ScienceDaily.com web site:
“There is no consensus among the scientific community about when the current mass extinction started,” [David] Wake [professor of integrative biology at UC Berkeley] said. It may have been 10,000 years ago, when humans first came from Asia to the Americas and hunted many of the large mammals to extinction. It may have started after the Industrial Revolution, when the human population exploded. Or, we might be seeing the start of it right now, Wake said.
But no matter what the start date, empirical data clearly show that extinction rates have dramatically increased over the last few decades, Wake said.
The global amphibian extinction is a particularly bleak example of this drastic decline. In 2004, researchers found that nearly one-third of amphibian species are threatened, and many of the non-threatened species are on the wane.
According to Wake, a virulent fungus is a major cause of frog extinctions, but he said that global warming and habitat constriction are two other major killers of frogs. He added that the amphibians in the Sierra Nevada that he studies are also affected by pesticides carried by the wind from nearby croplands. “The frogs have really been hit by a one-two punch,” he said, “although it’s more like a one-two-three-four punch.”
How can the advent of humanity be having the effect of driving tens of thousands of species into extinction. After all, the last time anything like that occurred, it took this to do the job:
How can we little ol’ harmless humans be doing anything to equal such a devastating event? Well, the answer is that we are dealing the environment with death by a thousand cuts. Remember that a trickle of water can carve a deep canyon, one tiny grain of stone at a time. Similarly, ever since the dawn of agriculture about ten thousand years ago, Humankind has been changing the Earth, one bit at a time. Each time a tree is felled, the Earth grew a little poorer. Each time a factory ship dredges the fish from the sea, the Earth dies a little. Each time a new power plant is fired up and begins to belch carbon dioxide into the air, the planet’s ecosphere shrinks by just a wee bit.
Now that there are nearly seven billion of us crowding almost every square kilometer of Earth, what was a trickle has become a torrent. Unlike a tiny stream that can take millennia to carve even a modest canyon, a surging tsunami can cause major change quite quickly.
That is a fair analogy to what is happening today, as the heavy footprint of humanity weighs on the once rich and diverse flora and fauna of our dear Mother Earth.
Unfortunately, we are like passengers who happily boarded a train to see where it would go, and now it has run out of control and is crashing off the tracks. The on-going extinction is running full steam ahead, and only now are we realizing that we are riding on the Extinction Express. As the diversity and richness of life on Earth continues to diminish, will even we humans be able to avoid the long, cold sleep of extinction? That is truly a question that we should consider.
What can we do about this? Sure, there could be some solutions, but there is woefully little sign of the kind of major commitments it would take to achieve them. Without strong motivation to change, it looks like we’ll continue to ride the train to oblivion.
The novel “Do Androids Dream of Electric Sheep?” by Philip K. Dick is about extinction. It is set in a future world when virtually all animal life has been destroyed and only humans remain. Humans still yearn for animal companionship, and robots are used to replace the extinct creatures. For example the hero of the book, police agent Rick Deckard, keeps an artificial sheep on the roof of his apartment building. (The movie Blade Runner was based on this book, although it does not include this critical part of the story from which the book’s title came.) At the end of the book (not the movie) Deckard goes into the desert and thinks he has found a living toad. He takes it home with great excitement. But when he shows his wife the toad, she turns it over and shows him the cleverly concealed compartment where the batteries go.
There’s one thing we can say about extinction, and that is that it lasts for a long, long time. In fact, it’s like diamonds which, as the de Beers company has always told us, are forever.