0.012%. That's all there is. — Roldano De Bastiani's Casbah

For roughly ten thousand years — from the dawn of the first civilisations to the early nineteenth century — the concentration of CO₂ in the atmosphere remained essentially stable: around 2.8 parts per ten thousand. A remarkably steady equilibrium, the one that made agriculture, cities, and history as we know it possible.

Then came the industrial revolution. In two hundred years — a blink in the life of the Earth — that concentration rose to 4 parts per ten thousand. Today we are at around 4.2.

Four against 2.8. The difference is 1.2 parts per ten thousand. That is 0.012% of the atmosphere.

I understand why people are not concerned. 0.012% sounds like nothing. Like a rounding error. Like something not worth arguing about.

And yet that is all there is. The entire problem fits inside that 0.012%.

Take an apple. Look at the skin. That thin film — a few tenths of a millimetre — is all that separates the flesh from the outside. Remove it, and the apple rots within days.

The Earth's atmosphere, in proportion, is just like that. If you could shrink the Earth down to the size of a common apple, the entire atmosphere — all the air we breathe, the clouds, the winds, the storms — would be as thick as the skin. A fragile protection.

That protection works because it lets the sun's heat in and releases part of it back into space. It is a delicate balance. CO₂ — and other greenhouse gases — acts like a blanket: the more there is, the less heat can escape. The planet warms. Climate systems destabilise.

You don't need a massive shift to break that equilibrium. We are watching the proof of this in real time.

The 0.012% we cannot see is changing everything else.

— R.D.B.