A planetary vitals observatory
Every year since 1880, measured, averaged, and laid down as a single stripe of color. Blue is cooler than the twentieth-century norm. Red is warmer. This is the whole record — no model, no forecast. Just the thermometers.
The reading that matters most is also the simplest: how far the surface of the Earth has drifted from the world our infrastructure, our coastlines, and our crops were built for.
2024 was the warmest year in the instrumental record — roughly 1.5 °C above the late-nineteenth-century baseline, brushing the threshold the Paris Agreement was written to avoid. A single hot year is weather. But the ten warmest years ever measured are the last ten, in order of recency. That is not weather.
Every year from 2015 through 2024 ranks among the ten warmest since records began in 1880.
Warming since the early 1980s is running about three times faster than the century-long average.
About 90% of the excess heat has gone into the ocean — energy equal to several Hiroshima bombs per second, every second, for decades.
In 1958, a young chemist began measuring the air on a Hawaiian volcano. The line he started drawing has never stopped rising. Scroll, and draw it yourself.
Atmospheric CO₂ · Mauna Loa Observatory annual mean · NOAA GML
Charles David Keeling installs an infrared gas analyzer at 3,397 meters on Mauna Loa, far from any smokestack. The air there is so well mixed it stands in for the whole hemisphere. His first annual mean: 315 ppm.
James Hansen testifies to the U.S. Senate that greenhouse warming has been detected. By now the curve has climbed 36 ppm. The measurement is no longer a curiosity; it is an indictment being written in real time.
Kyoto binds the industrialized world to cuts. The curve, indifferent to signatures, steepens — the fastest growth of the century arrives after the first climate treaty, as coal fires a new industrial ascent across Asia.
The year of the Paris Agreement is the first full year above 400 ppm — a level last sustained in the Pliocene, when seas stood many meters higher and horses grazed the Canadian High Arctic.
424.6 ppm — half again the pre-industrial level. Two-thirds of the entire rise since 1750 has happened within a single human lifetime. The curve's slope today is triple what Keeling first measured.
Take the same temperature record and bend it into a circle — one revolution per year, radius set by the anomaly. For a century the trace circles quietly near the center. Then it starts to spiral outward.
The cause and the cure share one picture. Forty years of the world's electricity, flowing as a river: fossil browns still carry most of the current — but watch the blue and gold channels widen at the right-hand edge.
Two-fifths of the world's electricity is now low-carbon — and solar, a rounding error in 2010, has become the fastest-growing source of energy in human history, doubling roughly every three years. The river is being rerouted. The question the rest of this page asks is whether it reroutes in time.
Heat is upstream of everything. These are three of its downstream signatures — slower, quieter instruments, all moving the same direction.
Since satellites began watching in 1993. The rate itself has risen — from 2.1 mm a year then to about 4.5 mm now. Rise is accelerating, not merely continuing.
The summer minimum has lost roughly two-fifths of its extent since 1979 — an area the size of Greenland gone from the top of the world's mirror.
The ocean is the planet's flywheel: it stores the heat and gives it back slowly. 2024 set the record — as did 2023, 2022, and 2021 before it.
None of these instruments knows about the others.
They agree anyway.
Thermometers on ships, gas analyzers on volcanoes, altimeters in orbit, floats drifting two kilometers down — independent machines, independent teams, one signal. A fever chart is not a prophecy. It is a description of the present, and the present is still ours to treat.
Series are annual means, transcribed and rounded for visualization; intermediate years in the energy and CO₂ series are interpolated between published anchor values. This page is a reading of the instruments, not a substitute for them.
PULSE is a fictional observatory built as a design study in visual climate journalism — in the tradition of the FT visual-journalism desk and The Pudding.