This is less of a blog post, and more of a howl.

The planetary climate clock, in human time

Let’s start by some human and planetary timescales. I don’t know why we don’t learn them in grade school (I never learned them at all). But they matter. And let’s represent them visually, in a stark, plain way.

“_” : this is our unit of time, and it’s 1000 years long.

_ is 10 long human lifespans, 40 generations, the time separating us from the first millennium and the Middle Ages in European history, when Canute of Denmark ruled Britain, before Marco Polo traveled the Silk Road. It’s a long time by any human account: twice the duration of the Roman Empire.

_____ is 5’000 years. It’s the age of the oldest known living tree, Methuselah, in the Californian White Mountains.

____________ is 12’000 years. It’s the time span separating us from the last ice age. This time is the time during which humans slowly selected plants, developed agriculture, cities, writing: anything we would call civilization. It is the time when humans thrived, cultures multiplied, our population grew. This clement and stable climate interval, which sheltered us and the plants we depend upon to live so well, is known as the Holocene. Gaze upon that interval fondly, for it is already in our past.

Image for post

Figure 1.2 from the IPCC’s Special Report on 1.5 degrees, showing that we have already left the temperature range of the Holocene.

_______________________________________________________________________________________________________ is 103’000 years: the duration of the last Ice Age. Ice Ages, compared with the Holocene, were pretty brutal times for human beings, and the plants and animals we depend upon. Human population was only 1–10 million at the end of the last ice age — and the one before that nearly wiped us out entirely.

__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ is 250’000 years, the rough age of Homo Sapiens, our species, us. This is the late stage of the Quaternary period: a time when our planet swung between ice ages and more clement interglacial periods (of which the Holocene was the latest one).

Now, time starts going much further back.

But stay with me (keep scrolling!): this is important. This is not just a distant past that our species never knew: it’s also a future we and our children will experience. Because time is moving slowly far back from us, but we are changing our climate with a rapidity never previously experienced on Earth. Ready? 3 million years to travel through now. Off — we — go!

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________1Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________2Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________3Million____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ is 3.3 million years ago. We have left the Quaternary and its ice ages: we are now in mid-Piacenzian Warm Period of the Pliocene. Temperatures are more than 3 °C (5.5 °F) warmer than today, and sea levels are 20 meters higher. Homo Genus has just appeared, a short 100’000 years ago, and Homo Habilis walks in South-East Africa.

New research, published in Nature, has now measured much more precisely how much of the warming gas carbon dioxide (CO2) was in the atmosphere during this warm spell: 360ppm (parts per million) on average. When my father was born, in 1921, a mere 100 years ago, the CO2 level in the atmosphere was only 304 ppm. By the time my son was born, our fossil-fueled civilization had barreled (joke? hahaha? ha?) past this Pliocene average, to 393ppm. So we are already, today, at CO2 concentrations higher than the Pliocene average: and we’ve moved the climate clock of the planet back more than 3.3 million years in less than 100 years: the lifespan of my father.

 

Image for post

CO2 concentrations in the atmosphere since 1700, overlaid with recent Pliocene study levels, and specific values from my family’s history.

If CO2 is so correlated with climate, why are we not already experiencing the temperatures and sea levels of the Pliocene, and witnessed by faraway Homo Habilis, with their almost-human eyes? Professor Gavin Foster, co-author of the Nature studyputs it this way: “The reason we don’t see Pliocene-like temperatures and sea-levels yet today is because it takes a while for Earth’s climate to fully equilibrate (catch up) to higher CO2 levels and, because of human emissions, CO2 levels are still climbing. Our results give us an idea of what is likely in store once the system has reached equilibrium.”

Time lags for equilibration vary between Earth systems: climate temperatures will catch up with the Pliocene with in a few decades, sea levels within a few centuries. But it gets worse. Because not only have we left the agriculture-sheltering Holocene. Not only have we zoomed through Pliocene the span than 1 human lifetime (reminder: we have no evidence that the large scale agriculture we depend upon, in our billions, for survival, is possible in this new climate. Cheers.). We are still going. We are accelerating, in fact, with concentrations of CO2 increasing faster and faster every year.

Image for post

The concentration of CO2 we are adding to the atmosphere is growing year on year: we are accelerating in the wrong direction. Plot source here.

And by 2025, according to the Nature study authors (my son will be 13! So awkward being a teenager while zooming through geological epochs, don’t you think?), we’ll have exploded CO2 concentrations so much that we have to go far, far, far further back in planetary times to find climate analogs. Is your down scrolling finger ready? Miocene, here we come!

________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________1Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________2Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________3Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________4Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________5Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________6Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________7Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________8Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________9Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________10Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________11Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________12Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________13Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________14Million________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ is 15 million years ago. The mid-Miocene. According to the Nature study’s lead author, Dr. de la Vega “Having surpassed Pliocene levels of CO2 by 2025, future levels of CO2 are not likely to have been experienced on Earth at any time for the last 15 millions years, since the Middle Miocene Climatic Optimum, a time of even greater warmth than the Pliocene.” 15 million years ago is not just an unfathomably long time ago in human terms. It’s quite simply a time before humans: before our human species, and even homo genus walked the Earth. It’s a time so far back our great-ancestors, the Hominids, had not yet differentiated into the branches that correspond to modern day orangutans, chimpanzees and gorillas, and, well, us.

Dr de la Vega’s result echoes a previous study published in PNAS, which showed that future Earth climates will likely resemble ones from our distant past. They compared past Earth climates from the early Eocene (50 million years ago — I won’t inflict that much down scrolling on you, but only if you promise to be good little climate activists and stop this trajectory of destruction, m’kay?) and mid-Pliocene, and found that on our current high emissions trajectory we would zoom through the Pliocene during this century, and end up in the Eocene by 2150. The Eocene, in terms of human-like life forms, well, that’s starting to go quite far back. At that time, primates were pretty much not differentiated, except for the lemur branch. If that’s any consolation.

It’s worth noting that many emissions modellers don’t believe that these high emission levels will actually materialize, but it’s also true that the climate response to emissions might be steeper than previously thought, so perhaps that’s not as reassuring as it should be.

Image for post

Figure from Burke et al in PNAS, showing past and future Earth climates, with Homo genus and species arrows overlayed.

Where do we go from here?

I want to make two short points here.

1: An avoidable disaster

The first is that the current trajectory we are on is both utterly devastating, and utterly avoidable. The loss of life, human and non-human, will be horrific. There is no way that ecosystems and species can adapt to millions of years worth of climate change in the span of decades. We are already in the midst of the 6th mass extinction and have destroyed biodiversity equivalent to millions of years of evolution of our own branches of the tree of life. This is not looking good.

It’s looking particularly bad for those least to blame. So far, I’ve been using the word “we”, as though “we” humans, young, old, poor, rich, were all equally to blame for our current trajectory. We are not. Some of us, specifically the affluent, have a disproportionate share of the blame, and are in fact driving the systems of global production and consumption, extraction, pollution and exploitation, that are causing our disastrous planetary roller coaster ride into a climate unknown to our species. Some of us, the majority world, the young, the poor, the Black and Indigenous and migrants and generally people of color, will suffer the most.

To give one simple example, on our current high emissions trajectory, the tropics will become uninhabitable within this century due to heat & humidity — see the map below. The map of countries with high historical responsibility for emissions is almost the reverse of this one, a clear demonstration of the injustice built in to climate harms.

 

Image for post

Figure of deadly heat & humidity days per year by 2100 from Moira et al in Nature Climate Change. (Yes this is RCP 8.5, but RCP 4.5 is not much better.)

But this immense harm is mostly avoidable, still. There is nothing predetermined about it. If we change our energy, consumption and production systems, to focus on sufficiency and decent living standards, we can both reduce our demand for energy while decarbonising our supply. If we change our diets to become plant-based, we can stop deforestation and remove a major source of methane and nitrous oxides, two potent greenhouse gases, as well as providing healthy and nutritious food to all. There is no historical evidence that we need fossil fuels to thrive, and looking into the future, we need to eliminate them to survive.

2: A struggle for survival

The second point I want to make is that we have a huge, immense struggle on our hands to achieve this livable, better (and entirely technically achievable) future. We are in a struggle for survival, and the odds are very much against us.

The main obstacles to our maintaining a planet on which the human species can thrive have names. Naomi Oreskes and Eric Conway, in their short and excellent sciency science-fiction book “The Collapse of Western Civilization: a View from the Future” named two culprits in the world of ideas: scientific positivism (the overcautious nature of current scientific communication) and market fundamentalism (the belief in markets-above-all enshrined in neoclassical economics and neoliberal policy).

In my research, I’ve circled around this problem, and come to name capitalism as the intertwined economic, physical and social system as the root cause of our current trajectory. Capitalism manifests itself in concrete ways, in the state capture by industrial interests which are antithetical to different trajectory (as we showed in the case of car dependency) and in the existence of ever growing inequalities, with the affluent most wedded to damaging patterns of consumption and production. The solutions put forward to comfort and maintain these existing power structures and inequalities, such as green growth, have been repeatedly shown to have no basis in reality.

This means that to avoid disaster, we must confront capitalism. That’s hard, certainly. But in my opinion, it’s probably easier than trying to cook a decent meal for one’s extended family of a few billion in the Eocene, you know? And fighting capitalism is definitely the topic for another post (or two or three — in the mean time you might want to read my “how to become a climate activist, just go do it already damn-it” trilogy).

But I did want to say a few words.

  1. It can be done.
  2. The history of learning how it can be done has been erased from our education. We don’t learn how to be activists, advocates, muckraking journalists or revolutionaries at school. But we can and need to learn this now.
  3. It takes the determination to become as revolutionary as we can.

Comfort and security are the past, if you ever had them. Many people never did. The Holocene is behind us. What lies in front is still undetermined, and can still be changed. But it will take the fight of our lives, for all of our lives, to change this. This will not be fun, or fulfilling, or a worthy adventure of self-discovery, or a cute feel-good movie, or a task of personal validation. I mean, maybe from time to time there will be those things, who knows. Who cares. This is a fight for life itself. We get to be depressed, despondent, little creatures against the crushing change of geological epochs and mighty economic systems. But we need to be little creatures who are learning to fight very very very fast and very very very well together against the brutal forces of domination which steer our current course.

So. Read Naomi Klein, Arundhati Roy, George Monbiot, Frantz Fanon, Rosa Luxemburg. Learn to become a revolutionary, get some courage and guts and analysis. Join Extinction Rebellion already, and/or the Sunrise Movement, and/or Fridays for Future, and/or all of them. Let’s do this. GO.

Teaser photo credit: King Canute and Queen Aelfgifu, date circa 1020, from the register of Hyde Abbey, courtesy of Wikimedia Commons.