On The Up: The Keeling Curve

Some time ago I posted a bit about the Keeling Curve. It’s a simple little thing, not hard to understand – every day, someone goes up to the top of Mauna Loa and takes an air sample, then measures the amount of carbon dioxide in it. When Charles Keeling started doing this back in 1958, the average CO2 was about 313ppm (parts per million),with a little seasonal variation.

In May 2013, the concentration of CO2 in the Earth’s atmosphere topped 400ppm for the first time. Last year, it exceeded that amount on March 12. This year’s benchmark crossing-400ppm-date?

January 1st.

It’s going to rise all the way from here to May or June before it falls. What’s this year’s record top figure going to be?

Remember that initial starting figure of 313ppm, in 1958? That wasn’t a lowest-figure-of-the-year, that was an annual average. So, what was the lowest figure recorded 2014/15, remembering that the Curve generally hits its low point in about September/October?


In 2013/14 that low point was 393ppm.

It’s well worth having a look at the record of atmospheric CO2 over the last 800,000 years. Most of that record, of course, is derived from ice core samples and not direct measurements, but if that spike at the end doesn’t worry you, all I can say is: you’re not like me. It worries me a lot.

It re-inforces other recent research results indicating that climate change has jammed its foot on the throttle and is heading straight for the edge of the cliff, and we’re still worrying about our economies and whether or not we’re paying enough into our pension pots.

Shouldn’t we be thinking about uncontrollable mass migrations on a scale never before seen, as approximately 23% of the world’s population decides living within 30 feet of sea level isn’t clever in a more hurricane/typhoon prone world? Not to mention the dropping crop yields as heat-stressed rice and wheat fail to grow normally? Does anyone think those hundreds of millions of climate refugees will wait for visas and immigration paperwork?

Don’t forget, the warmer it gets, the more positive feedback loops kick in to ensure it continues getting hotter, faster. Replacing reflective white sea-ice with heat-absorbing dark water, melting perma-frost releasing the frozen bogs of the tundra to rot and produce methane, destabilising methane clathrates to release (yet more) methane…. these all push the foot harder on the climate change pedal.

What about brakes?

Sulfur dioxide from volcanic eruptions can cause short-term climate cooling by preventing sunshine from reaching the ground, reflecting it back into space high in the atmosphere – but do we want lots of volcanic eruptions? Are we willing to bet on nature conveniently tipping off a few thousand extra large volcanos just when we need them? (At any time, about 1,500 volcanoes in the world are active – and they’re not slowing things down any at the moment!) And in any case, lots of sulfur dioxide in the air means lots of acid rain coming back down, sooner or later. Remember the troubles that caused, back in the 70s and early 80s?

How about more clouds? Clouds also block sunlight and reduce the temperature at the surface. Unfortunately, to get more clouds, we’d need more water vapour in the air and water vapour (unlike the water droplets in clouds) is a greenhouse gas, so that one may not work so well either.

Eventually, the Earth’s natural cycles will deal with all the carbon we’ve liberated into the air – but it will take hundreds, in some cases thousands, of years. Eventually, sea creatures building their shells from carbonates and dying, sinking to the seabed and forming silt will become new chalk and limestone deposits. Eventually, rocks weathering in the mild carbonic acid of rain will chemically react to remove the cardon dioxide from the air.

Any volunteers to wait that long? No?

There’s only one way to slow down the acceleration of climate change, and that’s to stop putting more carbon dioxide (and soot, and methane, and water vapour) into the air to begin with, which means we (humans) need to stop burning fossil fuels. Still no sign of any movement in that direction on the part of humans as a whole, so I don’t think it’s going to happen any time soon.

Which means, logically enough, that we’re still heading towards that cliff, pedal to the metal.

We ain’t seen nothing yet. But we’re going to, and I’ll bet we see it sooner than anyone’s expecting.


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