Mass Extinctions Part 4: The Holocene

The Holocene – the modern era. Or as the past few thousand years have sometimes been termed, the Anthropocene – the era of Man. This is where we set the stage for what might be the sixth great mass extinction in our planet’s biological history.

(As an aside, the name “sixth mass extinction” might not even be appropriate if another mass extinction is identified in the past. The Capitanian-era loss of biodiversity may or may not be a mass extinction; we haven’t decided.)

Unlike the other mass extinctions buried behind the sands of time, mysteries that we have to sift through the clues to find solutions for, it’s no mystery who’s to blame for the “sixth mass extinction”. Go on, point some fingers.

The Holocene extinction

Okay, don’t actually do that. And if you did, point back at yourself to make things even. Our entire species, you and I included, is the major, if not sole, culprit for today’s mass extinction. And that is not the scariest part of our current situation. The truth is that we have neither seen the full extent of the damage caused by the anthropocene, nor do we have someone accounting for it. Consequently, we don’t know how much can be attributed to modern climate change and how much is due to human activity, pre-industrial or modern. With powerful individuals around the world lobbying to support industries responsible for climate change to continue reaping billions of dollars, this trend doesn’t seem to be stopping, either.

In truth, recent research suggests that surprisingly, as horrific climate change is and as threatening it is to our continued survival, it isn’t the sole driver of the modern mass extinction. Our planet has experienced a long slew of traumatic events in its recent biogeographical history, chief of which began when the first farmer cut down a tree to grow his fields.

Farming is an integral part of human history, as our forebears supplanted fields and forests with crops to feed their families and grazing fields for their livestock. Unbelievable as it may seem, agriculture marked the beginning of the end for many species (other than megafauna, who were already dying out because of our hunting habits and the end of the last ice age). During the agricultural revolution, the human population exploded as large quantities of land were dedicated to producing food as efficiently as possible. Post-Neolithic farmers slashed down forests in wet seasons and burned them in dry seasons, driving deforestation in regions as far apart as Indonesia, Brazil and Europe. Rice demanded huge swathes of land for paddies, replacing forests in Asia, while livestock in almost every culture needed vast pastures for rearing and protection against predators.

Humans domesticated apex predators: dogs, especially, for their pursuit predation capabilities, were extremely useful for hunting. As time went on and our range expanded, we intruded upon more and more previously stable ecosystems, straining the food webs and overloading the resource capacity of these areas with our demands.

Time went on, kingdoms rose and fell, and yet agriculture was effectively a universal constant in all major human civilisations. By corralling economically useful plants and animals and allowing them to reproduce as much as possible while culling surrounding species to maximise resource availability for them, we simultaneously managed to exploit species’ natural growth and reproductive patterns to mass produce them with desired traits in controlled environments while wiping out entire ecosystems to fulfil agriculture’s demand for space.

And our species was just getting started. While the agricultural revolution was the spark that started the blaze, the Industrial Revolution and associated Great Acceleration were the fires that burned the forest to the ground. The International Union for Conservation of Nature estimates that 875 species have gone extinct due to our activity in the last 500 years alone, and biologists further estimate that the rate of extinctions has increased by at least 100x from the “base level” of extinctions in normal circumstances.

You know the rest of the story. Industrial farming has razed more forest cover than ever before. The ocean is becoming warmer and more acidic. Despite conservation efforts, there seems to be no abatement in the threat to our biodiversity.

Almost half of amphibians are at risk. One in four mammals and one in five reptiles are in danger. Since the 1500s, an estimated 187 bird species have gone extinct. Assuming a base rate of extinctions, only 5 species at most should have gone extinct in that time. The oceans bear the brunt of climate change (including temperature fluctuations, pH change and coral bleaching) as well as marine industries like seafood and offshore drilling, but the murky waters conceal what species may be facing extinction and make it difficult to track their risk. In every ecosystem on every continent on Earth, humanity has endangered biodiversity.

And yes, these changes have happened before due to non-human causes. Massive volcanism, huge climactic shifts and cosmic impacts have also led to anoxia, acidification and the erasure of millions of years of evolutionary history. These are patterns that we can see from the past that teach us what will happen if these changes continue unchecked.

But does it teach us about how we can stop it?

How to stop a mass extinction

It all seems rather hopeless. We are now reaping what humanity has sown for thousands of years, and it’s only really beginning. Surely, as we have seen from past experience, a few generations of humanity cannot undo the environmental damage perpetuated wilfully and unwittingly for generations?

While the past serves as a good predictor of our future Earth if humans continue their destructive ways, it is decidedly less useful in helping us find solutions. The biggest problem with looking to the past for answers is that humans are a relatively recent invention. For most of Earth’s history, the cause of extinctions have been indifferent abiotic harbingers of death, unable to take back what they’ve done or make amends. But humanity is capable of cognition, reflection, and decision – or indecision. There seems to be no real reassurance from history that we can reverse what’s happening simply because it could never have happened before. But ultimately, humans are social creatures that are consequently endowed with the unique power to wilfully stop their own destructive tendencies.

Humanity’s ability to change course gives us the most hope that we can make a shift – even if it takes the seemingly impossible task of making all the world’s leaders agree to prioritise the environment, it’s still less impossible than asking an ice age or supervolcano to have mercy. What kind of a mindset shift would this require, though? Can the past give us any lessons to point us in the right direction?

The mass extinction we are causing is merely the tip of the iceberg. The most important lesson we can learn from the past is that we don’t actually matter all that much to the Earth in the long term.

That’s right. Humanity, a mammal that’s proven capable of reshaping entire environments and ecosystems on a whim, is not a big deal in Mother Nature’s grand scheme of things. What we’ve seen is that after every mass extinction, the Earth recovers rather quickly no matter how horrific the fallout was. New species will emerge better adapted to the wasteland the previous extinction left behind, repopulating it with its own unique biodiversity. Life on Earth will continue, with or without humans, so long as the Earth continues to exist. This very simple condition is one of the few humans cannot violate.

The biggest problem humanity faces is not the destruction of the Earth. The planet, and life on it, will continue for millions of years in some shape or form. Our biggest problem is that among the species we are driving to extinction is Homo sapiens. Ourselves.

Our dependence on the natural world for our survival cannot be understated. Wars have and are being fought over food and water. As biodiversity fails, our vulnerability to pandemics increases. Every time a species goes extinct, we lose a potentially lifesaving cure to some emerging diseases we are susceptible to.

Taking action for the noble goal of protecting other species is incredibly valuable, but to the pragmatic masses it seems too remote a cause, one that runs counter to human interests. What might really make humanity stop and think about the long-term consequences of driving climate change is the threat to ourselves. Ultimately, the strongest reason to protect the environment is not a moral or idealistic one, but rather one steeped in individualism and self-interest that humans require a functioning environment to continue their existence.  We face economic crisis and societal collapse if damage to the ecosystem outpaces our ability to repair it, when fresh water becomes a scarcity, natural disasters plague every city, or heatwaves devastate our infrastructure and health. The accompanying loss of biodiversity may actually exacerbate climate change by releasing carbon from carbon sinks and reducing our ability to capture it.

This understanding, a reframing of the events of the natural world now, might help turn the tide and move people to action to stop the sixth mass extinction.

What needs to be done to save ourselves and the species around us is stunning in its sheer scale. Estimates place the area that needs to be fully conserved on every link of the food chain to prevent further biodiversity loss would cover about 44% of the Earth’s land surface. Previous commitments sought to protect 30% of the surface by 2030 and 50% by 2050, but the feasibility of this can be called into question as major governments have defaulted on climate agreements and repeatedly delayed the attainment of goals. The limited success of both the Kyoto Protocol and the Paris Agreement has highlighted how unlikely governments are to sacrifice individual gains to prioritise collective benefit through protecting the environment. Afforestation and reforestation to grow forest in areas that had it cut down or never had forest are productive steps, but their effectiveness is limited by how well the species of flora introduced interact with the existing ecosystem. Simply creating monocultures of the same tree will have limited effect, though new initiatives aiming to increase diversity and support indigenous species have begun to pick up momentum.

Beyond this, we need to reconsider the way we live as a whole. Beyond protecting habitats and swapping to plant-based diets, the very nature of the human economy must be reconsidered. Our pursuit of endless economic growth will only continue to strain what natural resources there are left, and only by reining in this thirst can we save the species threatened by the current mass extinction, including ourselves. Our paradigm must ultimately shift from “sustained” economic growth to “sustainable” economic growth.

It seems hopeless to even begin imagining a scenario where such a change could take place. But if somehow, we could all step back, reflect on our smallness and fragility, and consider protecting ourselves and everything around us as our highest priority, we could still try to save the world for future generations and beyond.

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Image Credit: https://heritagelincolnshire.org/blogs/the-holocene-extinction-by-jim-snee