A climate essay
Climate change is easy to state and hard to feel, and the reason is scale. The energy involved runs about twenty orders of magnitude past a phone charge, far outside anything a body has ever handled. So we climb to it. Start at one joule, change the unit four times, and count each step in the unit before it, until we reach a single surplus number that should not fit, and yet does.
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A joule is a small amount of energy. Lift an apple from the floor to a tabletop, about one metre, and you have spent roughly one joule. A single heartbeat is about one joule. Rub your hands together briskly for a second and you release a few. It is the plainest unit physics has, and for most of what follows you will not need any others.
A watt is different in kind. A watt is one joule per second, a rate rather than an amount. A hundred-watt bulb is not holding a hundred joules; it is spending a hundred every second it stays lit. The difference looks pedantic now, but it does real work later. The ocean's great heat conveyor and the surplus warming the planet are rates, energy per second, running without pause. The heat already banked in the sea is an amount, a total that has piled up over decades. Rates and amounts are not the same thing, and the essay ends on the gap between them.
We start small and climb. A single phone charge is about 54,000 joules. Drawn to scale against everything to come, it is this square: . Keep an eye on it. Every number in this essay is counted in squares like that one, and by the end there will be more of them than the page can hold.
One square is one phone charge. It is a small, everyday amount, the sort you spend without noticing. Hold it in mind, because from here on everything is counted in these squares.
Boil a litre of water and you spend a handful of them. The kitchen kettle already outruns the phone by several charges before the water even whistles.
A single day of food is a fuller grid. This counts the energy in the food itself, the calories a body takes in and burns, not the much larger amount spent growing and shipping it. Already the squares crowd the frame.
Fill a car and the squares stop being countable. A tank of petrol, counted as the heat its burning releases, scatters them into dust, a field too fine to tally by eye.
A year of a home's electricity is denser dust still. The single charge has not changed size; there are simply far too many of it to see.
So the field folds in on itself. All those phone charges pack down into a single new square: one home's electricity for a year, nothing else. That square is the new unit, and the climb begins again from one.
The new square is deliberately narrow: one home's electricity for a year, what comes through the meter. Not food, not petrol, not flights. The count starts from one again, which is the whole trick of changing units: shrink the ruler and the huge turns countable, at least for a while.
Now widen the lens. Everything an average person uses in a year — food, travel, heating, the lot — comes to about eight of these electricity squares. They are not the same unit: eight home-electricity years buy you one person's total energy for a year. The caption below is the conversion.
A whole lifetime of eating, eighty years of meals, is about 30 electricity squares. A single person's appetite, stretched across a life, still fits inside a small readable grid.
A year in the global top one percent is about 150 electricity squares, roughly 20 average people's worth of total energy in one life. The row of small figures below is those twenty. This is the same gap Who is heating the planet? measured in income, drawn here in energy.
Even that packs down. The whole grid folds into a single square, and the new unit is wider: everything one person uses in a year, not just what they plug in. From here we count in people.
The unit just widened. One square is now everything one person uses in a year — food, travel, heating, industry, not home electricity alone. The Hiroshima bomb was about 840 of them, released in one second. The field scatters into dust again, because eight hundred squares are already more than the eye can tally.
Hold that field in view. There are about eight billion of us, each spending one person-year square a year. In the next stretch we try to draw all eight billion, one square each, and watch the attempt fail on purpose.
You scrolled the whole strip and barely started. To reach the end of the field at this pace you would keep going for about hours, about screens of squares, one after another, without pausing.
And the field you just crossed is only a rounding error of the whole. World electricity, one year of it, does not end anywhere on this screen. It sits about 1.5 billion squares down — another × further than the strip you just finished. The full count, civilisation for one year, is about 8.3 billion. The count does not fit, and that is the point.
So stop counting people. The whole eight billion, one year of everything they burn and generate and eat, folds down into a single square. Call it one civilisation-year. From here the climb runs in that unit, and it does not last long.
One square is now everything, all of civilisation for a year. A single hurricane, dropping its rain for one day, releases about a twelfth of that square in latent heat alone. One storm, one day, fills the bar you see rising.
The ocean carries heat from the tropics to the poles, and it never stops. Measured as a rate, that conveyor moves about 100 civilisation-years of energy every year, square after square, continuously.
Now the surplus. The pale squares beneath are the ocean's conveyor from the last step, about a hundred civilisation-years. The greenhouse effect holds back a little more heat than the planet lets go, and that gap stacks the ember block on top, about 34 civilisation-years more. Not once. Every year, on top of everything else. This is the number that should not fit.
It does not vanish. Since 1971 the ocean has quietly banked about 640 civilisation-years of that heat, roughly 19 years of the current surplus, and about 90 percent of every year's excess still goes straight into the sea.
Here, for once, is the whole field, drawn square by square with none left out. Each one is a civilisation-year, and together they are one year of the sunlight the Earth absorbs, about 6,200 of them. The few ember squares scattered through it are the surplus, the same 34 you just watched refuse to fit. Against the sunlight it is a sliver, well under one percent. It is also the entire problem.
Spread that surplus back over the planet and it comes to about a watt and a third on every square metre of the Earth. Here is one such metre, one faint light. Stand in it and you feel nothing; a watt or so is less than the warmth of a hand held near your skin.
But it is not one metre. It is every metre, land and sea, day and night, and it never switches off. Your skin cannot feel a single dim light. The ocean, adding them up across its whole surface for decades, keeps the only ledger that can, and that ledger is what the earlier stages were counting all along.
Every square on this page is computed at load from the figures above. Nothing is drawn to a fixed count, so a revised source moves the picture with it. The joule values are single representative figures, not precise measurements, and a few are round by nature: a phone charge and a kettle boil vary by device, and the greenhouse surplus is a recent decadal average of a number that swings year to year. The ratios that carry the argument, roughly twenty average lives in a top-percent year and dozens of civilisation-years of surplus every year, hold across the plausible range of each input.