By Paul Robbins, Nelson Institute for Environmental Studies
This era of human impacts has represented such a radical geological and ecological change that many observers have considered giving our geological epoch an entirely new name—the Anthropocene. Evidence definitely demonstrates that Earth’s systems have been transformed fully enough by humanity to justify the renaming. But this really tells us very little. Is the Anthropocene a bad thing? Are human influences inherently bad for nature? Read on to find out.
Climate Change
Human beings have changed the climate. They’ve changed landscape and the diversity of life on Earth and, most importantly, the climate.
At least since the dawn of the Industrial Revolution, human activities have released high quantities of gases into the atmosphere. These gases have the potential to trap energy in the form of heat around the planet. Most notable out of all is carbon dioxide, but methane and other gases are also now found in far greater abundance.
Carbon-based Energy
When carbon-based fuels are burned, they release carbon dioxide that had been trapped either in the geologic strata or in plants. Once released into the atmosphere, CO2 is not dissipated and can reside in the atmosphere for a century or more. This is what boosts its capacity to warm the planet.
Current estimates suggest planetary warming on the order of two to three degrees centigrade in the next century. This alone is a significant human impact on the environment.
Expansion of Cropland
Another way humans impact the environment is by changing land cover. Land cover simply refers to the physical material covers that cover the surface of the earth. Understandably, it includes things like trees and grass, but it also includes agriculture, buildings, and asphalt.
Human activities, especially agriculture and industry, have directly resulted in the decimation of forests around the world and the dramatic expansion of cropland.
About 36% of the Earth’s surface that is considered bio-productive is dominated by humans. In addition to this, about 20% of the total productive capacity of the Earth’s life system is harnessed by human beings.
This article comes directly from content in the video series Understanding Cultural and Human Geography. Watch it now, on Wondrium.
Introducing New Species
Clearly, humans are a strong influence on the Earth. It is evident when sometimes plants and animals are intentionally introduced to new regions having a mixed impact.
Other times, species are introduced to new regions incidentally as a result of some other human activity. They might hitch a ride on an airplane, or they might be packed into packing crates and shipped across ocean to new continents and ecosystems, or, they might just escape, or be released, from aquariums or gardens, or people’s homes.
One such terrifying example is that of Burmese Pythons. Raised in captivity in southern Florida, Burmese Pythons have been released by irresponsible pet owners into the Everglades, and they’ve become a significant part of that ecosystem. Over 1,800 pythons have been removed from Everglades National Park since 2002. And, needless to say, they are most definitely not indigenous.
The Curious Case of the Cane Toad
Other invasions are the product of bad decision-making. The case in point—the cane toad. Originally introduced to Australia from Hawaii, the toad was intended to devour insects that prey on valuable sugarcane. Seems harmless, right?
So, the cane toad was brought in to improve agriculture. But, once it was introduced to the Australian environment, the toad ran amok. Not only did it not eat the insect it was intended to, but also began to expand at an alarming rate. And, because it was armed with poisoned sacks on its body, Australian predators were unable to kill it.
Unfortunately, this doesn’t stop predators from trying. Wild dogs and other animals that try to snack on the toad, die, causing a serious impact on the predator population of Australia.
Overturning the Indigenous Ecology
The cane toad also successfully reproduced at an amazing rate. So, it has now colonized many parts of Australia. It already occupies a huge part of the tropical eastern and northern parts of Australia.
If the cane toad can jump the central part of this desert continent, which is possible, there is no reason to think it won’t dominate the southern shores of the continent, totally overturning the indigenous ecology of Australia in the process.
The cane toad is merely one example of an exotic species that has become invasive, and indeed, so successful as to out-compete native species, even to the point of driving some to extinction.
In Hawaii, in a counterexample, the common housecat was introduced in the last century. Unfortunately, it is its feral descendants that are putting pressure on dozens of critically threatened native bird species.
Is There a Solution?
Although it’s impossible to know how many invasive species there are around the world, but, one figure gives us a sense. According to the U.S. Fish and Wildlife Service, there are 50,000 species in North America that are not native to this continent.
In conclusion, it is right to agree with the many observers of our current global environmental predicament who look at all this evidence and conclude that it’s time for despair.
Humanity has, indeed, so fully transformed the Earth in the Anthropocene epoch that our only hope is to disengage from environmental impacts and retreat to a simpler ecology and economy.
Common Questions about Anthropocene and the Human Influence
Human activities, especially agriculture and industry, have directly resulted in the decimation of forests around the world and the dramatic expansion of cropland.
About 36% of the Earth’s surface that is considered bio-productive is dominated by humans. In addition to this, about 20% of the total productive capacity of the Earth’s life system is harnessed by human beings.
Species are introduced to new regions incidentally as a result of some other human activity. They might hitch a ride on an airplane, or they might be packed into packing crates and shipped across ocean to new continents and ecosystems, or, they might just escape, or be released, from aquariums or gardens, or people’s homes.
