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Human dominance of Earth has come at a steep cost to our planet

Opinion: in an incredibly short period of time, we have endangered a world that took billions of years to evolve - Dr. Paul Bolger, Manager, Environmental Reseaarch Institute

In mid-December 2020, just about the time we were buying our last online Christmas presents, a new scientific paper published announced that human-made material now outweighs life on Earth. The research showed that the weight of concrete, metal, plastic, bricks and asphalt produced by humans exceeds the overall weight of living biomass on the Earth.

This startling finding on the accumulated mass of human artefacts provides further empirical evidence that the Homo sapiens species can no longer deny its central role in the world. It requires us to re-think how we perceive humankind in the context of millions of other species of plants and animals on Earth, and the influence we are having on these species and on our earth system.

Since the scientific revolution started 500 years ago, we have come to the dawning realisation that humans are just a tiny part of the entire web of life on our planet looking outwards on a very large and mostly lifeless universe (at least no other life discovered so far).  


Trailer for Anthropocene: The Human Epoch documentary on humanity's massive re-engineering of the planet

Within those five centuries, we have had an agricultural and industrial revolution that has enabled us to support 7.5 billion people living longer and physically healthier lives than any time in our human history. This has been and continues to be a tremendous achievement for humankind. But it is now clear that it has come about at a steep cost to our home planet. In an incredibly short period of time, we have put ourselves in the unenviable position of endangering a world that took billions of years to evolve.

The data on the scale of human impact can numb us, but here are five striking earth system trends to consider:

(i) Since the dawn of the industrial revolution, levels of carbon dioxide in the atmosphere have increased by almost 50%.

(ii) Human activities across the world move more rock and soil each year than is transported by all other natural processes combined.

(iii) Factories and farming remove as much nitrogen from the atmosphere as all of Earth's natural processes.

(iv) Populations of fish, amphibians, reptiles, birds, and mammals have declined by an average of 58% over the last 40 years and extinction rates are running at 1,000 times the rate before humans walked the earth.

(v) If we weighed all the large mammals on the planet today, just 3% of that mass is living in the wild, while 97% of the mass is connected to human activity. 

From RTÉ Radio 1's Inside Culture, Fionn Davenport and guests on what the Anthropocene is all about

One of the most thought-provoking concepts in science in recent times has been that we are moving out of the current, relatively stable Holocene geological period to a new human-dominated period called the Anthropocene, a term coined in 2000 by the late Nobel Laureate Paul Crutzen. Almost 20 years later, a panel of international geologists and scientists voted to designate the Anthropocene a new geological epoch to mark the profound ways in which humans have altered the planet.  

So what's new? Haven’t humans always altered their environment? Yes, that is true. Even in hunter-gather times over 40,000 years ago, humans exerted a significant toll on their biological environment resulting in extinctions of mega fauna. However, it is the scale and pace of environmental change in the last 50 to 100 years which has led many scientists to dub it the Great Acceleration. A rapid rise in human population and consumption has come with accelerating environmental impacts.

Whilst scientists are still in some disagreement about whether the Anthropocene really constitutes a new geological period, and about when it may have begun, there is more than a little merit to highlighting the central role that humans now have in driving the earth system. The Anthropocene reflects human's current unique position in dominating the health of the planet. A widespread acceptance of this fact might bring an understanding of our responsibility that we need to feed, cloth, warm, cool, entertain and keep healthy a probable 10 billion of our species by the end of century without destroying the crucial life supporting systems such as water, climate, and ecosystems on which we depend. 

From WWF International, how the incredible growth of human society in the Great Acceleration has had a huge impact on our planet

In 2019, I had the privilege of visiting Biosphere 2 in Oracle, Arizona. In the early 1990s, this 3 acre closed ecosystem was designed and stocked with soil, air, water and plants along with eight humans to see if we could prove human life could be independently sustained.  After eight months, the experiment was abandoned due to dangerously high carbon dioxide and low oxygen levels, illustrating how difficult it is to artificially create life sustaining conditions.  

The famous biologist E.O. Wilson once said that "we have only one planet and we are allowed one such experiment. Why make a world-threatening and unnecessary gamble if other options are available?".  Acknowledging the Anthropocene forces us to think like what public philosopher Roman Krznaric calls a "Good Ancestor" and about what kind of world we will bequeath to future generations.