Skin in the game – a tattoo of the Keeling Curve

Today I got a tattoo. Mrs Hudson (not her real name, or title, in fact) has plenty – crows, beetles, angels of the apocalypse etc.

Me? When my turn came, I went for a Keeling Curve. The lovely and steady-handed tattooist I went to (Deviant Ink, in Stone, Staffordshire) knew exactly what it was, and enjoyed the challenge of the straight lines. His colleague didn’t know, and tolerated my explanation of the curve and the broader explanation of climate change/carbon dioxide build-up (see below for that)

The Keeling Curve is named for Charles (but he went by Dave) Keeling. Keeling measured the amount of carbon dioxide in the atmosphere to very very accurate levels. The measurements began in 1958, as part of the International Geophysical Year. Roger Revelle had managed to find a bit of spare money, and Keeling did the rest. (It now emerges that before doing it for Revelle, Keeling had been doing it for an oil and gas lobby group beforehand – see Rebeca John’s work on this).

It wasn’t absolutely certain that carbon dioxide had been increasing in the atmosphere (though people had a hunch that it had been), because previous efforts to measure carbon dioxide had been confounded by trees, industry nearby etc. The results, such as they were, were messy, noisy. What Keeling did was show that the amount of carbon dioxide in the atmosphere was in fact, indisputably, increasing year on year. Thanks to isotopes and so on, it was also certain that the increase came from the obvious suspect – the burning of oil, coal and gas, aka “the Industrial Revolution” of the last two hundred years.

The Keeling Curve has changed over time (I have various documents going back to the early 1960s that show it, initially fairly flat and unimpressive, if you didn’t have imagination to see where it would end. One day I’ll make a montage, and play David Rovics’ Here at the End of the World over it. Or maybe Anonhi’s It’s only Four Degrees.) The CO2 level in 1958 was 315ppm. Now it’s bumping along at 428ppm or so. Back then numbers were going up at about 1ppm per year. Now, with much more oil coal and gas being extracted and burned, with deforestation galloping on and with ocean acidification kicking in, the “natural” systems that drew down a certain amount of the carbon dioxide from the atmosphere are, well, faltering, and therefore we are seeing annual increases of carbon dioxide of 3ppm per year. And don’t even start me on the methane….

The y-axis (vertical) measures carbon dioxide in parts per million. The x-axis (horizontal) is years (I didn’t have numbers added to the x and y axis because they smudge over time and who needs them?)

Me and the greenhouse effect

I have been switched on to “the greenhouse effect” since 1989 or so. I have been convinced that “we” (as a species) were not going to respond adequately since 1991. It has shaped my life, my intellectual interests, everything – including the very conscious decision not to have children (taken in 2003 and acted upon in 2004) because, to quote a very stable genius “the second half of the twenty-first century is going to make the first half of the twentieth look like a golden age of peace, love and understanding.”

So a Keeling Curve? It’s a bit like the skull that scholars would have on their desk in the Middle Ages – a kind of memento mori, only at a civilisational/species level, rather than an individual level.

That metaphor wot I promised.

Here’s what I used to explain the Keeling Curve to the the other tattooist (getting her permission).

“You’re lying in bed on a Sunday morning. Not too warm, not too cold – like the porridge that Goldilocks steals – just right. Your mum comes in and says “get up you lazy so-and-so” and pulls off the duvet. Instantly you are too cold. Or – sliding doors – your mum comes in and says “oh, darling, have another duvet” and throws one on. For a moment the extra warmth is nice, but pretty quickly you overheat.

“Well, the Sun is 6 and a half light minutes from earth. If all the heat that hits the Earth bounced off it would be 18 degrees below zero. But there is a duvet of gases – carbon dioxide, water vapour, some others – that trap a certain amount of the heat. Over the last two hundred plus years, we have been making that duvet thicker. Every time we burn oil, coal and gas, to get electricity, make heat, whatever, carbon dioxide is released. Some of it gets pulled out of the air by trees or the oceans, but more of it stays there. The Keeling Curve (points to tattoo) measures how thick the duvet is. So all the stuff you hear about renewables this, nuclear that, whatever – the key thing to ask is “is this making the duvet thinner, or is it even slowing down the rate that the duvet is getting thicker?” And the answer is no.