On mass extinctions and the obstinacy of life on Earth

3.7 billion years: this is the age of life on Earth.

Together with its majestic balances, the planet has many more, but it is clear that it has undergone numerous transformations throughout its existence. Frequent catastrophes alternating with periods of environmental stability have allowed life on Earth to develop into all the shapes and colours we know. Don't get me wrong: the fact that there are many varieties of species does not mean that surviving on Gaia was something easy or spontaneous, quite the contrary. However, it seems impossible for humanity to fully become aware of the fragility of life, distracted as we are from exploiting the planet without mercy.

Everything we have built outweighs the entire terrestrial biomass. For this reason, the period we are in has been called Anthropocene, characterised by a consumerist vision of life and all living beings. This idolatry of the present does not make us notice two quite evident things: the Earth is finite and very ancient. Planet Earth is about four billion years old, and from what we currently know, it is the only planet in the entire solar system to host life. What's more, it is the only planet we know carved out by life. A tenacious, stubborn life that has manifested itself in multiple beings and that in its long history has been crossed by not one, not two, but by five mass extinctions. And we have officially entered into the sixth.

The 26th edition of the United Nations Conference on Climate Change will be held in Glasgow, Scotland, from the 31st of October to the 12th of November. One hundred ninety-seven nations will participate in discussing and negotiating new measures to contain CO2 emissions. Therefore, it is time to dispel our false beliefs about life on our home planet to understand what is really at stake. Spoiler alert: it's an old story repeating itself, but this time it's our fault.

MORS TUA VITA MEA

We often take it for granted that the variety of life on Earth has always undergone a linear path, with one exception: the extinction of the dinosaurs. Popular beliefs had progressed little compared to when we were convinced that the skeletons of dinosaurs were God's experiments in search of the perfect creature (which, according to our narcissism, would be us). The dinosaurs weren't the only ones to vanish from the face of Earth, and God has nothing to do with it: there have been five mass extinctions on our planet, and they all have to do with the environment and climate.

The first major mass extinction occurred 2.5 billion years ago. At the time, the Earth was a wasteland devoid of oxygen. The oceans were rich in dissolved iron and anaerobic microorganisms (which evolved to resist and thrive in an oxygen-free environment) dominated the young Earth. We do not know exactly when the cyanobacteria arrived on the scene; however, cyanobacteria weren't that different from anaerobic microrganisms: they too produced energy from sunlight. Except that in the process of extracting energy, they released a waste gas: oxygen. They released oxygen in their surroundings, and they ended up filling the seas and the air with this element. Cyanobacteria compromised the livelihood of the poor anaerobic microorganisms by altering the planet's chemistry irremediably. They did so by compromising their own existence too since it is assumed that their wastage reduced the presence of greenhouse gases in the atmosphere weakening the capacity of the planet to retain heat. They are believed to be the culprit of a long, dark, cold global winter that decimated the cyanobacteria themselves and almost all life on Earth.

It is incredible that something like oxygen, which we take for granted for our very existence, was the cause of the largest mass extinction on the planet. This gives us a first clue as to how survivors react to the disappearance of other competing species: they grow, evolve and differentiate. Oxygen has been the cause of death for many and the starting point from which countless other lives have developed. On the contrary, the Devonian, Permian and Triassic eras were dominated by devastating volcanic explosions that released carbon dioxide into the environment, compromising the planet's climate (does this sound familiar?). The fifth mass extinction in the Cretaceous was caused by an asteroid from space, the size of Mount Everest, which crashed in Mexico. The impact released a sheer amount of energy that triggered an absolute pandemonium, throwing incandescent debris into the atmosphere and making the air as hot as that of a furnace. With sunlight obstructed by the materials injected into the upper atmosphere by the vaporised asteroid, the temperature plummeted, dragging the planet into a winter that wiped out the last surviving dinosaurs and nearly all other life forms.

Among the few survivors, holed up underground, were our ancestors, similar to mice, the only mammals existing at the time. And even in this case, as happened with chlorophyll photosynthesis, the fateful demise of the dinosaurs has paved the road to mammals. Life has gone on, diversifying, more flourishing than it was before the extinction event.

How is it possible that the more species die, the more are born? It seems that extinctions not only give space to new species but encourage innovation in evolution. The climatic and environmental balance established between one catastrophe and the next allows us to exist on Earth. This balance cannot be counterfeited, imitated or reproduced, not even by an intelligent animal such as a human being. Our life is a break between successive apocalypses. Breaks we are increasingly shortening due to the economic and development model that Western cultures have championed around the world.

ON HUMAN EXTINCTION

By focusing on our species, it is wrong to ask whether we will go extinct. The right question is: when will we die out? Because the end of the human species is inevitable, asking when this will happen is more interesting. It may not happen very soon: we are many, we live scattered in all sorts of environments, from the North Pole to the jungles. We are not even that picky when it comes to food: we eat everything, vegetable and animal, you name it. Not to mention the extraordinary intelligence we possess that makes us indeed the most powerful species on the planet. Our passing will not be immediate, but we are not above the forces governing our home planet and the universe.

What can we do to prolong our existence and stop the sixth great mass extinction we have started? We must do exactly what we did during lockdown: we had better not move. In 2020 there was a decrease in CO2 emissions, which reached an average of -27% per country. Such low figures have not been recorded since 2006. Due to COVID-19 restrictions set up by governments worldwide, humanity had to give up means of transportation such as cars, trains, and aeroplanes. Air flights have been reduced by 75% compared to 2019. The global pandemic has shown that human behaviour is decisive for the fate of the climate.

Today we consume everything, not just the goods. We consume content in the digital world, consume food that we don't finish, and throw away. We consume hectares of land. We consume other human beings to the point of putting a price on various aspects of their lives. We consume gasoline, vast amounts of fossil carbon that we put into the atmosphere every year.

Consumption has absolute dominion over our lives. It has sneaked into our vocabulary, changed definitions and downgraded us from citizens to consumers. On the one hand, a citizen has rights and duties for the mere fact of being a human being, while a consumer has as many rights as he can afford to buy. As the word itself says, consumption means wearing out, and it is exactly what is happening to our lives. Economic science tells us about goods that are completely or partially destroyed to satisfy our needs. This commodity fetishism has made us so addicted to the point we are so convinced that the smooth omnidirectional plane of the market is equivalent to reality. The idea of future and past makes no sense at all because they are useless horizons when every need is satisfied on-demand. Our reality must be consumed, and our home planet exploited. The natural world seems to be in the background of our busy lives, a world that resembles a theatre. We are inside it. We are the actors. A theatre in which we, the actors, have begun to set on fire.

The industrial society that we have built over the past 150 years is a destructive model for the living beings on the planet. In other words, anything that makes our lives simpler, safer, and more comfortable damages the biosphere, and it is not good news for humanity's survival on Earth. Acting to stop this catastrophic trend is not a work out of charity or favour that we render to the natural world because it can live very well without us. The problem is precisely our long-term survival. The odds are not very favourable to us if we keep on the same track.

We now live on a planet that is this century warmer than it is in geological terms has happened in a rapid time. We can still save ourselves by changing our lifestyle and the foundation of our economies or doing nothing instead.

In that case, who knows how many present and future species would benefit from our extinction.

This essay has been supervised by Michela Fantozzi, Digital Content Writer

BIBLIOGRAPHY

1) MASS EXTINCTIONS MADE LIFE ON EARTH MORE DIVERSE – AND MIGHT AGAIN, NICHOLAS R. LONGRICH

https://theconversation.com/mass-extinctions-made-life-on-earth-more-diverse-and-might-again-122350

2) GLOBAL HUMAN-MADE MASS EXCEEDS ALL LIVING BIOMASS, EMILY ELHACHAM, LIAD BEN-URI, JONATHAN GROZOVSKI, YINON M. BAR-ON, RON MILO
https://www.nature.com/articles/s41586-020-3010-5

3) INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE (IPCC) REPORT 2021, SUMMARY FOR POLICYMAKERS, PAG. 8
https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM.pdf

4) HOW TO AVOID A CLIMATE DISASTER. BILL GATES, PAG. 25

5) CLIMATE CHANGE: SUMMERS COULD BECOME ‘TOO HOT FOR HUMANS’
https://www.bbc.com/news/science-environment-53415298

6) COVID CURBED CARBON EMISSIONS IN 2020 — BUT NOT BY MUCH

https://www.nature.com/articles/d41586-021-00090-3

7) IPCC REPORT 2021, SUMMARY FOR POLICYMAKERS, PAG. 16-17-18-19

8) IMPACT OF COVID-19 ON CO2 EMISSIONS
https://unfccc.int/sites/default/files/resource/1.GCP_.pdf