Burning Down the House

In order to change our collective future, we have to change the names we use to describe the present.

The Pyrocene Has Arrived

When I reread my recent essay, “It’s the End of the World as We Know It,” I noticed something about the language: I had used the present continuous tense repeatedly. The climate is changing. The Pyrocene is arriving. The world we have known is becoming something else.

There's something reassuring about that tense. It describes a process that is underway. Something is happening, but it hasn't happened yet. We are suspended between the world we inherited and the world that is coming. However, I no longer think that tense is adequate. Instead, let's use the present perfect: The climate has changed. The Pyrocene has arrived.

We are in it now. Get used to it.

That may sound unnecessarily bleak, but I have a specific meaning in mind. I'm not suggesting that we surrender to climate change. I don't mean that mitigation no longer matters. I certainly don't mean that the future has already been determined. What I mean is that we need to recognize where we are.

For decades, climate change was presented primarily as a warning about the future. Scientists told us what would happen if greenhouse gas concentrations continued to rise. Temperatures would increase. Glaciers and ice sheets would melt. Sea levels would rise. Heat waves would intensify. Conditions favorable to extreme wildfire would become more common. In short, if we continue as we are, dangerous things will happen.

We continued. And now many of those things are happening. The warning was about the future. The predicament is about the present.

Confirmation of that shift arrived as I was writing this essay. On September 2, 2026, the United Nations Environment Programme (UNEP) released a report with an unusually stark conclusion: exceeding 1.5°C of global warming is now widely assessed as unavoidable. The question is no longer simply how to prevent the world from crossing that threshold. Instead, UNEP now speaks of an “overshoot, peak and decline” pathway: limiting how far temperatures rise above 1.5°C, limiting how long they remain there, and adapting to the consequences, with the eventual goal of bringing temperatures back down.

The 1.5°C threshold was one of the great warning markers of the climate-change era. Now the United Nations has told us to prepare for a different kind of world. The future we were warned about has become the condition from which the future must now be made.

The name we have traditionally given this predicament is climate change. It is an extraordinarily bloodless expression. After all, climate changes all the time. Seasons change. Weather changes. Temperatures rise and fall. The words climate change themselves do not convey danger.

Even global warming has an oddly gentle quality. Warmth is something we normally seek. We warm ourselves beside fireplaces. We travel to warm places during the winter. But there is another name for this new world. Fire historian Stephen J. Pyne calls it the Pyrocene – the Age of Fire.

That lands differently. People don't need scientific training to understand fire. Fire burns skin, destroys homes, and kills. Increasingly, fire reveals what would otherwise remain dispersed across atmospheric measurements, carbon concentrations, temperature anomalies, vapor pressure deficits, and climate models. Fire transforms difficult-to-see relationships and turns them into flame.

Therefore, the Pyrocene should not be understood simply as "the age of wildfires." While wildfire is its most spectacular manifestation, something larger is occurring. The Pyrocene is characterized by the accelerating relationship between the atmosphere, carbon, vegetation, climate, technology, and human institutions. At the center of this relationship lies fast combustion. In particular, the exponential rise in industrial combustion, what Pyne refers to as the third fire.

For several centuries, industrial civilization performed an astonishing trick. We extracted ancient carbon from beneath the Earth's surface and burned it inside engines, furnaces, and power plants. We domesticated fire. Or at least we thought we did. Turn the key. Open the valve. Ignite the burner. Stop the engine. Fire became our servant.

While we controlled internal combustion, we progressively lost control of the conditions surrounding the flame. The byproducts of combustion did not simply disappear. Carbon dioxide accumulated in the atmosphere. The controlled combustion began altering the conditions of the uncontrolled combustion.

The genie escaped the bottle.

The Monster

Perhaps that is why I can't stop thinking about another metaphor. A monster has arrived. Not literally, of course. Climate change and fire are not creatures. However, monsters have always allowed us to give narrative form to frightening forces that exceed the ordinary human scale. This particular monster has an unusual characteristic, though: it is a shapeshifter.

Fire has no single form. Depending on the configuration of fuel, moisture, wind, and atmosphere, it can creep along the forest floor. Change those conditions, however, and it races through grass. Change the conditions again, and it climbs into the canopy. Under extreme conditions, wildfires can exhibit firestorm behavior, generating enormous convective columns and producing pyrocumulonimbus clouds that can transport smoke and embers high into the atmosphere.

The monster changes because the field changes. There is no single entity underlying all these manifestations of fire with one immutable identity. It is fundamentally a chemical process. The form that fire takes emerges through its relationships with fuel, terrain, moisture, wind, vegetation, infrastructure, and atmosphere.

The monster has no name because the monster has no single form. Instead, we have named the age in which it appears – our time now – the Pyrocene, the Age of Fire.

That is frightening. It should be.

We are adapting to a moving target, and there is growing evidence that the target itself is shifting more quickly. In geological terms, Earth remains an icehouse planet, characterized by large, permanent polar ice sheets. Human civilization arose during an unusually stable period within this icehouse world. Yet, we are now rapidly pushing the climate away from these familiar conditions toward a much warmer planetary state.

We should be careful here. A full-geological-greenhouse Earth is not a predetermined destination awaiting us at the end of this century. Where we end up depends substantially on what we do next. However, this should not distract from what has happened: we have placed ourselves on a warming trajectory, moving away from the climatic regime in which our civilizations, agricultural systems, coastlines, and infrastructure developed. There are also increasingly strong indications that the climate changes along this trajectory are accelerating.

The evidence is not based on a single unusually hot year. In fact, a recent paper published in Geophysical Research Letters found that the planet has been warming at its fastest rate on record over the past decade. The authors noted that the world has been warming at a rate of approximately 0.2°C per decade since the 1970s but has "accelerated" since 2015 to a rate of 0.35°C per decade. While some of this acceleration may be due to natural variability over short periods, other physical measurements point in the same direction.

One of the most important measurements is the Earth's energy imbalance, which is the difference between the solar energy the planet absorbs and the heat it radiates back into space. Data from NASA's Clouds and the Earth's Radiant Energy System (CERES) satellites show that the imbalance nearly doubled from the early 2000s to the 2020s. Specifically, the planet has been trapping heat at a rate exceeding 1.0 W/m², compared to 0.5–0.6 W/m² in the early 2000s. In short, the Earth is accumulating excess thermal energy significantly faster than in previous decades.

Most of the excess heat does not remain in the atmosphere. Instead, it enters the oceans. More than 90 percent of the excess energy accumulating in the climate system is absorbed by the oceans, which makes ocean heat an especially important measure of long-term planetary warming.

Looking back, the oceans gained heat roughly twice as fast during the 2010s and 2020s as they did during the 1980s and 1990s, reflecting the Earth’s increasing energy imbalance. Recent years have witnessed the largest single-year heat gains on record, providing another indication that the accumulation of energy continues beneath the noisy year-to-year fluctuations of surface weather. To make matters worse, we are currently experiencing the onset of a historic El Niño event.

The United Nations’ World Meteorological Organization (WMO) underscored the point, issuing an urgent global warning about the phenomenon’s impact. In response, U.N. Secretary-General António Guterres cautioned that "El Niño is being supersized before our eyes," and warned that the combined effects of climate change and ocean warming have pushed the planet into "uncharted waters" and the "danger zone of extreme weather."

At the same time, one of the forces that had previously concealed some greenhouse warming has weakened. Industrial sulfate aerosols reflect sunlight and alter clouds, producing a temporary cooling effect that masks some of the warming generated by greenhouse gases. But reductions in sulfate aerosols have eliminated much of this cooling effect.

The cryosphere is also responding. Ice sheets and mountain glaciers are losing mass, and terrestrial seasonal snow cover is retreating earlier across North America and Eurasia. Remember that sea ice and snow cover act as giant planetary mirrors. Fresh snow reflects 80 to 90 percent of incoming solar radiation back into space, whereas open, dark ocean water absorbs about 90 percent of that same solar energy.

Arctic sea ice has exhibited the most significant and consistent long-term reduction of any oceanic ice cover. Since satellite records began in 1979, summer minimum extent (measured each September) has declined by roughly 12% to 13% per decade. Additionally, winter ice expansion around Antarctica has suffered persistent anomalies, regularly falling 1.5 to 2 million square kilometers below historical averages. Over the past century, glaciers in the European Alps, the tropical Andes, western North America, and high mountain Asia have lost an estimated 20% to 40% of their total area.

In brief, surface temperature, ocean heat, planetary energy imbalance, melting ice and reduced snow cover are all manifestations of one underlying fact: the Earth is accumulating energy. The consequences of this accumulation are spreading throughout the planetary system.

Importantly, we have not transitioned from one stable climate to another. Rather, we are moving along a trajectory. Today's extraordinary event may become tomorrow's reference point, and tomorrow's extraordinary event may lie beyond that.

As a result, the Pyrocene is not a destination at which we have arrived. It is a trajectory we have entered – and there is ample evidence that we are accelerating along it.

We know enough to understand the direction of the trajectory, but not exactly where it leads. How much warming will ultimately occur? How will particular ecosystems respond? Which thresholds will be crossed? We don't know.

That uncertainty is not reassuring. The monster has arrived, but it has not reached its final form.

The Monster Feeds On What We Burn

The monster metaphor is particularly useful here because recognizing that we are living in the Pyrocene could lead to the wrong conclusion. If the climate has already changed, why bother doing anything?

Because the monster is getting bigger.

Carbon dioxide accumulates. Therefore, what matters for long-term warming is not simply the emissions produced in any particular year, but rather, the cumulative amount added to the atmosphere over time. Each additional quantity of fossil carbon that we extract and burn adds to that cumulative burden. The predicament has arrived, but its eventual magnitude has not yet been determined.

The monster feeds on what we continue to burn.

For decades, much of the discussion about climate change has revolved around net zero. From a scientific perspective, this concept is extremely important. In order to stop contributing to CO₂-induced warming, humanity must eventually reach a point at which anthropogenic carbon dioxide emissions are balanced by anthropogenic removals. Net zero describes that balance.

However, when the term "net" leaves the realm of climate science and enters the world of politics and the public imagination, it can become problematic. When the solution is seen as something in the future, it becomes tempting to imagine that we can continue emitting enormous quantities of carbon today and compensate for them tomorrow through forests, carbon capture, direct air capture, or other technologies that have yet to operate at anything close to the required scale.

That is an extraordinarily dangerous wager to make with the atmosphere.

If our objective has shifted from preventing climate change to mitigating the effects of an ongoing climatic transformation, then another principle should accompany net zero. Call it real zero.

To put this in perspective, absolute zero is neither possible nor desirable. Agriculture, industrial processes, and other activities will produce residual emissions that are extraordinarily difficult to eliminate. Therefore, carbon removal will have a role. Still, the goal should be to reduce gross fossil fuel emissions to the minimum that cannot be avoided rather than assuming that large-scale future carbon removal will allow us to continue extracting and burning carbon now.

Net zero tells us where the balance must eventually lie. Real zero shows us the direction in which fossil fuel combustion must travel: downward toward the minimum we can possibly achieve.

This means leaving more and more fossil carbon underground, where it was originally deposited by geological processes.

This distinction matters because every ton of coal we don't burn means we don't have to remove that same amount from the atmosphere later. Each coal seam left untouched, each barrel of oil that does not combust, and each quantity of fossil gas that is replaced by non-carbon energy represents carbon that never enters the active atmospheric cycle.

Mitigation therefore takes on a different meaning once we understand ourselves as inhabitants of the Pyrocene. It is no longer just about solving a future problem. Rather, it is about altering the trajectory of our current predicament.

Or, in the language of our monster story: let’s stop feeding the monster.

Our Time Now

We were warned. For decades, scientists have described the eventual effects of continued greenhouse gas emissions on the planet. We did not respond adequately. The climate changed. The Pyrocene era has arrived. Now, the monster is here.

The United Nations' latest assessment makes it difficult to avoid acknowledging the change in our circumstances. The world is now expected to surpass the 1.5°C threshold that we spent years trying to avoid crossing. The remaining task is to limit how far above the threshold we go, how long we remain there, and the amount of damage that occurs along the way.

Recall that the monster has no single body because it has no single form. It appears differently depending on the relationships through which it emerges. Sometimes we see it in flame. Sometimes in smoke. Sometimes in extreme precipitation events. Sometimes in drought, ecological transformation or a food system pushed toward its limits. It is still changing, and we don't know how powerful it will become. Even worse, there is growing evidence that some of the physical processes driving this transformation are accelerating.

But we are not powerless. We still have some control over the trajectory. We can stop feeding the monster by quickly reducing the amount of fossil carbon we extract from the ground and release into the atmosphere. We must abandon the comforting fiction that we are outside the system, passively awaiting the solution to a future problem that someone else will solve someday.

That future has become the present. Climate change was something we were warned about. The Pyrocene is where we now reside. Get used to it.

How much worse are we willing to let it become?