April 22nd, 2021: Earth Day.

In 1992, at the Earth Summit in Rio de Janeiro, the UN adopted the Convention on Climate Change with the aim of limiting greenhouse gas emissions. Every year since 1995, the Conference of the Parties (COP) is held among the 188 member states of the Convention. COP-3 (1997) and COP-21 (2015) marked two milestones in the international climate debate: the first adopted the Kyoto Protocol, whereby industrialized countries committed to reducing carbon dioxide emissions by 7% from 1990 levels; the second led to the Paris Agreement, which has the goals of 1) limiting the global temperature increase to below 2°C, and 2) reducing CO2 emissions by 45% by 2030. COP-26 will be held in Glasgow from November 1-12, 2021.

Awareness is the first step towards change: we have been aware of the climate emergency since 1970.

“We are in a crisis of survival.”

These are the words of Barry Commoner, American biologist and politician, on the very occasion of the first celebration of Earth Day. Twenty million U.S. citizens, including many university students, take to the streets to protest against industrial pollution. His speech is broadcast by CBS News, in a report titled "Earth Day: a question of survival".

If you're not part of the solution, you're part of the pollution.

Masks to protect yourself from the air you breathe: though we are still in the Seventies, the increase in air pollution due to industrial emissions of CO2 triggers the first international events for the protection of the environment. World Earth Day is born from the private initiative of citizens who feel the threat of climate change, and is then adopted and promoted by the United Nations.

“Do not forget why you are attending these conferences, who you're doing this for. We are your own children. You are deciding what kind of a world we are growing up in.”

Severn Cullis-Suzuki becomes known as "the girl who silenced the world for 5 minutes". At just 12 years old, she scrapes together the money for an airline ticket from Canada to the International Climate Summit in Rio de Janeiro and gives a speech in front of the United Nations. Her idea of change is as simple as it is radical: stop destroying things that can't be fixed.

"Our house is burning and we look away. Nature, mutilated, overexploited, is no longer able to recover and we refuse to admit it. Global warming is still reversible. The responsibility of those who refuse to fight it will be heavy.”

In 2002, ten years after the Rio Summit, Jacques Chirac reminds the COP-17 assembly in Johannesburg that nothing had changed. Awareness of failure must lead to a global climate alliance: France and the European Union are ready to engage in the fight against climate change.

“The world shrinking down about a raw core of parsible entities. The names of things slowly following those things into oblivion. Colors. The names of birds. Things to eat. Finally the names of things one believed to be true. More fragile than he would have thought. How much was gone already?”

From Cormac McCarthy's novel The Road. In a post-apocalyptic world (very probably destroyed by an environmental catastrophe) where there is no more humanity, but only survival, a father and son travel on foot to the sea to escape. The sea is gray, as are all things. Even words slowly give way to oblivion: the words of colors, of trees, of birds, the last memory of an extinct reality.

The Galician visual artist Isaac Cordal presents a series of works entitled "Waiting for Climate Change" at Voyage à Nantes, a cultural event in Nantes, France. "Follow the leaders" represents, in the form of small wax sculptures, a ruling class that is progressively submerged by water. It is a metaphor for the debate — the one on the climate emergency — whose timing and arguments grow old together with those who are its interlocutors.

“When the trees fall, and the native animals are slaughtered, the native germs fly like dust from a demolished warehouse.”

Spillover is U.S. science writer David Quammen's book on the "species jump" of pathogens from animals to humans. With a foresight more eloquent today than ever before, the author explains why some major human activities — including, in particular, deforestation — contribute to the spread of pandemics.

“Clean air and a livable climate are inalienable human rights. And solving this crisis is not a question of politics, it is a question of our own survival. This is the most urgent of times, and the most urgent of messages.”

Leonardo DiCaprio participates, as United Nations Climate Peace Ambassador, in the New York Summit that lays the groundwork for the Paris Agreement. His documentary Before the Flood is a journey around the world that marks the boundary between the "point of no return" and the future.

“We are the first generation to feel the impact of climate change, and the last generation that can do something about it.”

The United States is the second largest emitter of greenhouse gases in the world: Obama admits it publicly in his speech at COP-21, which sees the birth of the Paris Agreement. Obama adds that the nation intends to change course drastically. His was a message of hope: the realization of the emergency is combined with the awareness of the progress being made.

"Although the post-industrial period may well be remembered as one of the most irresponsible in history, nonetheless there is reason to hope that humanity at the dawn of the twenty-first century will be remembered for having generously shouldered its grave responsibilities."

With the encyclical letter “Laudato Si”, the Catholic Church officially enters the climate change debate. Recalling St. Francis of Assisi's Canticle of the Sun, Pope Francis reiterates the indissoluble link between nature and humanity, and therefore between environmental crisis and social crisis, calling on the faithful — and especially politicians — to embrace what he calls "integral ecology".

“The eyes of all future generations are upon you. We will not let you get away with this. Right here, right now is where we draw the line. The world is waking up. And change is coming, whether you like it or not.”

A little over a year after her first climate strike in front of the Swedish parliament — which gave rise to the international movement "Fridays for Future" — Greta Thunberg speaks at the UN Climate Summit, delivering harsh words on the ineffectiveness of the Paris Agreement. Her iconic words "How dare you?" leave no room for misunderstanding: continuing to ignore scientific evidence means condemning those who will live long enough to experience the consequences.

Devastating hurricanes, wildfires, and other natural disasters sweep through the world in a year where the global populations already suffer under the pandemic. The unprecedented level of catastrophe is a wake-up call for many: no part of the world was safe from the effects of climate change. NASA reports that 2020 officially ties with 2016 as the hottest year on record.

We can still choose to change the course of history.