Greetings on the December solstice, one of the two days of the year when the earth is most tilted. People in ancient communities observed this planetary extreme in traditions, holy days, festivals, and even architecture. I find myself thinking of these long-dead folks as I learn more about the planet I live on, its patterns, and the other people and species I live among. Whether making mundane, everyday decisions or reflecting at the end of a year on this often-tilted world, I find myself, like them, increasingly grounding my assessments and judgments in the physical and natural. 

Over the past year, fires burned across many parts of the world, heat records were repeatedly shattered, wars with ancient roots flared, and computer scientists unveiled software programs that would synthesize internet-available human writing to answer any question, no matter how profound or picayune. In the hopes that you will find it helpful or at least interesting, I have decided to take this occasion to share with you the ways that learning about and working on climate change have challenged, changed, and clarified my view of human life. This is an essay about power, morality, humility, and seeing the divine in a graph.

In the beginning, there was skepticism

In June 1988, James Hansen testified in front of a US Congressional committee that the warming trend over the 1980s was almost certainly due to increasing concentrations of carbon dioxide in the atmosphere. “Global Warming Has Begun, Expert Tells Senate” read the headline just below the masthead of The New York Times the following day. At that time, there was no debate among scientists about whether carbon dioxide and methane had the power to trap more heat (Eunice Foote published an article about that way back in 1856), but Hansen went further. His research indicated that recent warming and charting the path of further, perilous future warming, depended almost exclusively on carbon emissions from fossil fuels and deforestation. It was us.

The forces that govern Earth’s atmosphere are complex. The sun is a dynamic, raging inferno; different surfaces absorb sunlight while others reflect it; the earth is spinning, tilting, and wobbling; water is cycling within the oceans, between the oceans and atmosphere, and between atmosphere and land; plants and animals are growing and dying; some dead plants and animals are decaying and releasing their carbon into the atmosphere, while others are being buried, trapping their carbon underground. Hansen and some other scientists were declaring that, while all of that complexity was real, the effect of human emissions of greenhouse gases had begun overwhelming the effects of all the other determinants of atmospheric temperature. Many scientists thought this seemed too simple. An equation with lots of potentially important variables reduced to just one? It didn’t sit right that complexity could be so simplified—or that our fate, and the fates of all other living things, rested in our hands.

To indigenous communities and to believers of more humble faiths, the idea that humans could single-handedly upset nature was self-evident. Indeed, indigenous communities saw their ability to burn forests and grasslands as an awesome power to be used with caution and respect for other life. Western scientists in academia and industry, in labs, office buildings, and factories remained skeptical (although those at Exxon privately agreed that Hansen was right). Over time, though, the data obliterated other explanations. Critical scientists interrogated the data and found that it really was that simple. 

Perhaps most famously, Richard Muller, a physicist at the University of California, Berkeley who thought that previous studies of the causes of climate change had flaws that made their claims about the primacy of greenhouse gases suspect, got a grant from a foundation funded by conservative oil billionaire Charles Koch to tell the real story. Muller and colleagues assembled the most robust set of temperature readings and other data, expecting to find a messy, twisted plot in which humans were just one character. Instead, the data led to a conclusion that Koch and his brother probably didn’t like. Muller wrote an op-ed in The New York Times. The opening paragraph starts with, “Call me a converted skeptic.” It ends with, “Humans are almost entirely the cause.”

Muller is one of many scientists who, one after the other, have come to the conclusion that it really is that simple. As the data keeps going one way, the “it is more complicated” cohort is now just a collection of ideologues and opportunists. By burning fossil fuels and felling forests, humans are warming the atmosphere and fundamentally altering life on the only planet we know to have life on it. 

Hansen was trained as an astrophysicist and worked at NASA. The idea that someone could be an astrophysicist and that a nation would build and fund an atmospheric and space administration is a testament to the ways in which humans have taken advantage of climate stability. Only if life is going well does it make sense to have people follow their imaginations into space, and only if the nation has powerful tools could they do so productively. 

The more time I sit with the results of climate science, the more profound I find it. Twelve thousand years of climate stability enabled people in successive generations to focus ever more narrowly on specific domains and pursue more esoteric questions. Eventually, a combination of scientists in labs, scientists out on glaciers, scientists in forests, and scientists in offices all had enough tools (not just obvious scientific equipment, but freezers, snowmobiles, glass, semiconductors, and dot matrix printers) to examine the deep past, the atmosphere, and the sun and discern what caused what.

It is a strange story. Westerners trampled over native lands from the 15th to the 20th century, often led by the conviction that the naturalistic worldviews of indigenous people were simplistic, irrational, and barbaric. Over centuries, advanced by scientific discovery and fueled by burning what became known as fossil fuels (power derived from long-dead life), industrialization spread, which enabled further scientific advances. Eventually, like some kind of M.C. Escher print, scientific studies wound around, one step at a time, to the realization that the key tenets of indigenous wisdom were correct: We are intertwined with the complex natural world, and our expanding use of unnatural powers is wrecking it. This cycle of dismissing a prior wisdom and then ultimately discovering that wisdom after quite a lot of suffering isn’t just about climate. As I wrote about in a past essay, my life has been saved by medical advances to treat a disease that didn’t exist before industrialization changed the human microbiome.

I find this whole process of figuring out how our world works and discovering that we have the power to destroy it to be perhaps the most amazing outcome of civilization. The ingenuity, cooperation, and discipline to learn these profound truths speaks to what humans can accomplish. It also makes clear that with each new bit of power and awareness comes a challenge that is far older. I don’t know Muller or Hansen from Adam, but what I have learned from them—and the thousands of other scientists who have contributed to this body of knowledge—has made me far more interested in the divine. At the risk of being called a heretic, please allow me to tell a story that is consistent with the facts.

A flight of historical fancy

Imagine a deity who, with a bang, creates a universe governed by complex physical rules and relationships. The deity then watches to see what happens. Over billions of years, the materials created in that bang move, collide, combine, and change. In most places, the results, while often fascinating and sometimes beautiful, are sterile. But over in one part of the universe, on one planet orbiting one star, things get interesting. A specific balance of heat, light, hydrogen, oxygen, and carbon leads to something new: life. The deity takes notice.

Over hundreds of millions of years, life gets more complex and funky on the changing planet. As it turns out, life evolves. Some things evolve to live under water, some on land, some between the two. The temperature of the planet changes gradually over time with changes in the sun’s intensity, eruptions of volcanoes, asteroids colliding with the planet, and movement of the continents. With each change, different forms of life emerge. After a swampy period dominated by awesome lizard-like beings, the atmosphere cools, eventually falling into a protracted cold spell that oscillates between milder times when 10% of the planet is covered in ice and harsher ones when 30% of the planet is. On land, animals that generate heat fare well.

Among these heat-generating animals (the deity calls them mammals) emerges a creature that, at first, doesn’t seem that promising. It has no protective shell or hide, its young take years to be anything close to mature, and it isn’t particularly strong. But as they multiply, these creatures (the deity calls them humans) start doing some distinctive things. They seem to figure out their surroundings; they explore; they use tools; they take voyages. Their small groups develop increasingly complex language and customs, including stories, songs, sculptures, and satire. Humans are now the most interesting thing in this universe (whales are fascinating as well, but without opposable thumbs, they can’t build anything, and they aren’t able to burn entire forests). The deity decides to see what humans could do.

It has been about 190,000 years since the first of these humans was born, and that entire time the climate has not only been shifting but has mostly been very cold. So the deity, who thus far has not intervened in this universe, decides to make life easier for the humans. It adjusts the temperature of the atmosphere to be ideal for the human body, an average of about 288°Kelvin (about 15°C or 60°F, but the deity uses absolute zero as its reference), with nowhere on the planet too hot for humans to live. The effect of this stable, ideal temperature is impressive. Humans build permanent structures, further manipulate other plants and animals, master materials, and develop more sophisticated knowledge and expressions. So the deity keeps the climate in a narrow band around that ideal temperature and observes, keenly interested. 

In different places, humans live differently. They experiment with different forms of governance, agriculture, and social arrangements. They also develop different theories of how they came to be and what governs life on Earth. 

After more than 10,000 years of stability, humans have radically reduced the forest cover to make grasslands for hunting, grazing, and farming. They start to specialize further and develop tools and frameworks to both better understand the physical rules of the planet and to gain more power over it. They develop machines—powered first by burning the remaining forests and then by burning the underground remnants of hundreds of millions of years of buried dead plants—that make it even easier for them to manipulate the earth and dominate other species. 

Over these millennia of stability, the deity has been paying attention to the beliefs of the various human communities. There are different characters in their stories, and the prioritization of principle and practice differs between them. But in the majority of cases, adult humans teach their young to be respectful and humble, to not be violent toward others, to value modesty and discipline, and to take responsibility.

The deity notes, however, that although all young humans seek kinship with plants and animals, and many older communities see humans as members of the community of living things, a group of people who started in Europe and the Middle East assert that the natural world was given to them by a deity, as theirs to use and dominate, as background. It isn’t surprising then, that as these humans and their worldviews gain more power and spread into new lands, other species are disappearing. Humans may be getting more interesting, but the planet is getting less so. The deity notices that the mass of humans, their livestock, and their concrete and steel now vastly outweigh everything else on Earth. Indeed, they are starting to even foul up the space around them with garbage. So the deity decides to test humans. 

What would be a good test of these increasingly sophisticated, social beings, especially the ones who are so interested in seeking power and disinterested in other forms of life? What if they came to understand that if they wanted to maintain the ideal climate they were given, the climate that every community depended on, they would need to do three things: Respect all life on the planet, cooperate across communities, and exercise restraint? Those seem like the values they espouse in their religions and teach their young.

The deity decides to create a threat that humans could discover on their own. The threat would need to be easy for humans to understand and completely in their control. It couldn’t be an asteroid. The deity sets the test: Hidden in the record of the planet’s past would lie both evidence that the climate could be much hotter and that the concentration of carbon in the atmosphere governed temperature. 

In this way, humans would be able to see that they were vulnerable and would really only need to do one thing: Work together to stop burning other forms of life. The deity was legitimately curious: Would this interesting species recognize the warnings, work together, and follow the principles of humility and restraint?

The line still goes up

This hypothetical may sound fanciful or blasphemous to you, but after first having this thought years ago, I find it more and more compelling as time goes by and graphs go up.

NASA continues the work started by Hansen and his team. Here, from the NASA website, is the concentration of CO₂ in the atmosphere—we are now at 422 parts per million:

Under the leadership of his daughter Elizabeth, Richard Muller’s endeavor to track global temperatures as accurately as possible has continued. Berkeley Earth is now considered a premier source of current and past global temperature data. Below is the latest update, including a range of estimates for the final 2023 value (in essence, forecasting just a couple of months out). Most likely, 2023 will wind up having been 1.5°C or more above the pre-industrial average. Note how early in the decisive warming trend Hansen’s warning came.

After I began working on climate change, I started getting a particular kind of email. They were from parents asking if I would talk to their children about climate change. Without exception, the children are interested in or worried about climate change and the parent doesn’t feel equipped to help them. 

I welcome these emails and enjoy the conversations with the young people. The younger the child, the more likely they are to ask things like, “Why don’t we stop doing this?” and “Are the animals sad?” The older the child, however, the more likely they are to have gone to college, to have been educated by the consensus cultural opinion that what we need is innovation, growth of new things, and scale. They often ask me personal questions about mental health and personal behavior, but it is easy to sense that they believe that they are supposed to be focused on technological solutions. The extreme (and extremely influential) version of this worldview is espoused by the now-powerful techno-optimists. I think it is worth examining.

We need more power!

It’s possible that 2023 will be remembered for being the first year to pass the 1.5°C threshold.¹ I wonder, however, if 2023 is more likely to be remembered as the year that we all started realizing how fervently a group of very well-funded people who excel at math and logic, and to whom we are paying a huge amount of attention, believe that more power is the answer to every moral question and that slowing down is anathema.

Days before his OpenAI firing-turmoil-rehiring fracas dominated the news, Sam Altman was interviewed by New York Times journalists and asked about the potential dangers of artificial intelligence. He replied, “Yeah, I actually don’t think we’re all going to go extinct. I think it’s going to be great. I think we’re heading towards the best world ever.” What I find fascinating about this is the lack of specificity and probabilities here. It’s clearly a bet, and he is taking one side of it, which he describes as “the best world ever.” OK, but what makes it the best? Who is in the “we”? If we’re “heading towards” it, is there much margin for error? And what are the odds?

Instead of grounded, earthly specifics or characters and stories, conversations among tech, crypto, and libertarian pundits often wind up in fantastical hypotheticals. If these folks were academics, that would be one thing. But they are building the infrastructure of the future with other people’s money, so it’s not academic, even when it sounds like it is. In a conversation with crypto-huckster, hedge-fund fraudster, and now-disgraced philanthropy guru Sam Bankman-Fried, the academic economist Tyler Cowen (a wide-ranging thinker whose own philosophy is rooted in maximizing human good and who proselytizes on behalf of markets) wanted to understand how strongly Bankman-Fried held the utilitarian views he espoused. 

Cowen: Let’s say there’s a game: 51 percent, you double the earth out somewhere else; 49 percent, it all disappears. Would you play that game?

Bankman-Fried: With one caveat… just to be a party pooper… I’m assuming these are noninteracting universes. Is that right? Because to the extent they’re in the same universe, then maybe duplicating doesn’t actually double the value because maybe they would have colonized the other one anyway, eventually.

Cowen: But holding all that constant, you’re actually getting two Earths, but you’re risking a 49 percent chance of it all disappearing.

To translate: In this hypothetical, a very slightly biased coin flip determines whether everyone on Earth dies or we get to live and there is another planet that has the same number of people as this Earth somewhere in a noninteracting universe. I find the structure of the question fascinating because a) both men understand that “you double the earth” means that you get another planet with the same number of people on it (i.e., the unit by which earth is measured is human population), and b) it takes our planet for granted and postulates that, out somewhere else, there is another planet with a bunch of things like a presumably stable, hospitable atmosphere. Bankman-Fried tells Cowen he would take the hypothetical bet, so long as he can be assured that there wasn’t any possibility that humans on our planet would colonize the other planet anyway. 

This hypothetical may seem trivial, terrifying, or simply out-there to you, but it is representative of a worldview espoused by crypto bros and AI accelerationists. The freak-out at OpenAI was about the possibility of slowing down. It is a modern version of the kind of worldview that human cultures—including modern, Western culture—consistently counsel against. Many of the most popular movies are about futures in which artificial intelligence leads to what few would consider the best world ever or in which, trying to have two worlds, humans wind up with none. 2001: A Space Odyssey, Star Trek: The Motion Picture, both Blade Runner movies, all of the Terminator, Matrix, and Avatar movies, and many others are modern versions of tales told in almost every ancient culture about the dangers facing societies led by hubris, lust for power, and simplistic assumptions about human primacy.

We made the maps on probablefutures.org with a different mindset. We figured that if they were vivid and easy to use, people could make decisions informed not by vague notions of utopia or dystopia, but by excellent, practical science that gave mundane information like the number of days a year it would be dangerous for a human to go outside, or the probability of a year-plus extreme drought. Investigate these maps and you will find that at 1.5°C of warming, nights are warmer everywhere, droughts and deluges are more common, and local climates have shifted. It is a world of challenges, but one in which there is ample space to live well if we help one another. Look out to 2.5°C or 3.0°C above the stable ideal, and while you won’t see Mad Max or Dune, you will see a harder world to live in, one that is difficult to imagine as the best one ever, no matter how powerful and free the technology and money are.

Looking further ahead and further back

James Hansen and a number of coauthors recently published a new academic paper filled with graphs new and old that offers new warnings and a moving ending.

First, they warn that the effect on atmospheric warming as we reduce the amount of polluting aerosols (largely from oil and coal particulates, which cause more cloud formation and make the atmosphere hazier) is larger than most current estimates. In the following graph, the black dotted line is the same as the Berkeley Earth graph above. The yellow fan is their estimate of what’s coming, as aerosols in the atmosphere decrease and warming that is already baked in is realized.

Second, the paper, whose title is “Climate Change in the Pipeline,” argues that the pathway we are on will lead to more, faster loss of glaciers and thus more, faster sea level rise. As an aside to the glacier loss analysis, they ask a question that fits exquisitely with my hypothetical: Was the earth on its way to being a nearly lifeless block of ice if humans hadn’t mucked around with the land?

We conclude that, in the absence of human activity, Earth may have been headed for snowball Earth conditions within the next 10 or 20 million years, but the chance of future snowball Earth is now academic. Human-made greenhouse gas (GHG) emissions remove that possibility on any time scale of practical interest. Instead, GHG emissions are now driving Earth toward a much warmer climate.

In other words, for thousands of years, before using fossil fuels, human action stabilized the earth’s climate. It perfectly offset the cooling that would have been happening. It was as if our species was being favored, given a chance to see what it could do. Those long-dead ancestors who noted the equinoxes and solstices and saw the divine in the physical world kept nature in balance. Then we started to seek as much power as we could get our hands on, and even after we were warned about limits, we kept demanding more power.

The paper is new, and other scientists have pushed back saying that Hansen’s work is just well-educated conjecture, but in private, scientists have told me the paper reflects the evolving story. 

The paper’s conclusion is speculative, but it is one that I have wondered about for a long time, and it fits with the story I told above. Hansen writes, “We should aim to return to a climate like that in which civilization developed, in which the nature that we know and love thrived.” In other words, we will have to swiftly stop adding carbon to the atmosphere and will need to repair what we have broken and continue to break. 

I don’t want to discourage investments in new technologies, innovation, and scale. We absolutely need them. But those will be insufficient without restraint and humility.

Facing a modern problem with old and new values

I write these letters with the admittedly imprecise goal of increasing the chances that the future is good and decreasing the chances that it is bad. To do so, I search for what we have in common, what motivates people, and what is missing from society and its institutions that could help us deal with climate change in ways that would provide an abundant world for living things, old and young, human and otherwise.

If the hypothetical deity were watching us now, it would see that the warning has been heard by many around the world. A lot of people have worked very hard to encourage cooperation. Whatever the outcome of the recent COP in Dubai, it’s worth noting that, like ancient communities honoring the wonder of the physical world on the solstice, tens of thousands of people were drawn together by the state of our planet. If the deity expected nothing of us, it would be impressed. Indeed, on many days I am impressed by how many people are actively trying to help our species be better and pass on not just healthy values but a wondrous planet to our children.

I (nervously) share the story of my hypothetical deity because, having spent time over the past few years consulting the teachings of Abrahamic religions, Buddhism, Libertarianism, and Ecofascism, I believe the teachings that guided communities when the climate was stable are helpful but insufficient for overcoming our current challenge. Some newer faiths are dangerous to apply. What is good and evil? Naughty and nice? We need some new moral frameworks. We have the building blocks to make them, but they are not easy. 

Here is a list of moral questions that I think about:

• How do we value both members of our own families and faiths and people far away?
• How do we treat our relationships to place when we know there will be hundreds of millions of immigrants? 
• How do we include other living things in our values?
• How do we make our communities resilient and prepared for hard times while also planning for good times?
• Should we believe that a small number of people (including me) have the right to eat whatever we desire, buy anything we want, and go wherever we choose because we can afford it?
• How do we emphasize the values of restraint, humility, and charity?

The above questions often humble me with their enormity. But when I go through them slowly, deliberately, I can envision a very good future, a future in which humans have lived up to the challenge we all face and have discovered truly better ways of living, being, and thinking.

We will only get to such a future with experimentation, not just in science and technology but also in the humanities, customs, and religion. The challenge of climate change can encourage us to find ways of living, teaching, and storytelling that are resilient and sustainable, that satisfy common shared values, and that widen our scope of empathy to include other people and other species. I am hopeful that appeals to you, no matter your faith.

Thank you for reading my letters and for whatever you are doing to help our species find its way.

Onward,

Spencer