Our CO2 emissions are not the half of it

Human emissions of CO2 1990 to 2010.
From PBL Netherlands Environmental Assessment Agency.

Two days ago we heard about the long-term trend in atmospheric carbon dioxide emissions, copied above.

This graph functions as a fine graph of productive output, and doesn’t it reveal the new world order? The countries with the highest emissions are (broadly speaking) doing the most work, making the most money and having the most influence.

It was ever so. If our leaders wake up to that simple fact they might be able to make sensible plans to maximise our work. Perhaps improve on the half-baked notion of a magic “knowledge economy” — as though knowledge alone would succeed without the application of intelligent planning, consistent effort and good service.

Though the authors have put the USA contribution at the bottom, the country can hardly be disregarded; it’s still second most productive in the world — for now.

Anyway, apart from 2009, when, curiously (even in China), emissions actually declined by one per cent, total human emissions are still rising.

We’re often told about our filthy emissions, but never about the amount left in the air. For example, we’re never told the fact that Nature absorbs about 40% of our emissions, no matter what they are. It’s magic!

If mankind’s emissions of carbon dioxide are responsible for the general increase in atmospheric concentration since industrialisation in about 1750, you’d expect to see a good correlation between emissions and the amount in the air. But human emissions are just one aspect of the great carbon cycle.

There are gargantuan emissions of carbon dioxide from plant and animal life, oceans and sea life and volcanic activity, and at the same time the oceans and sea life, forests and other plant life and rock-forming processes pull tremendous quantities of CO2 back out of the atmosphere. Our emissions add about 4% to this natural flux.

What’s the result? How do the changes in atmospheric levels of CO2 compare with our puny emissions? Do they pace each other?

Here’s a good general record of global CO2 concentrations:

Atmospheric CO2 levels (click for large version). From Earth System Research Laboratory, run by NOAA.

This must have been done before, so please forgive this amateurish approach. If you imagine the yellowed section of the Mauna Loa graph stretched horizontally to the same width as the emissions graph, it doesn’t look as though the two slopes match very well, especially if you consider that the Mauna Loa Y-axis doesn’t start at zero.

If you can do better than this, would you kindly do the maths and tell us how they correlate? Email me the workings and the graphs and I’ll post ’em for everyone to see.

I’ve seen a couple of efforts around the internet, including at Sceptical Science, but I don’t automatically trust everything John Cook presents.

Anyone like to volunteer, or point us in the right direction for an example?

UPDATE 25.9.2010 15:15 NZDT

Mike Jowsey has sent us the following graph (thanks, Mike):

Human emissions of CO2 versus atmospheric concentration from 1990 to 2010

The green area shows atmospheric levels of CO2 and it rises steadily for the whole of the period covered — so steadily that at this resolution it looks like a straight line.

The blue area shows human emissions of CO2 which vary somewhat while mostly rising over the period.

Of course, we’re interested in the lines marking the top of each area. The two lines show some similarity but strong differences too. I’d be surprised if the correlation is strong.

It’s clear to see the regular monthly rise in the atmospheric quantity and equally clear that human emissions are much more irregular. If it’s true that our emissions are responsible for all of the increase in the atmospheric level, then we must see some response in the level to fluctuations in the emissions.

We apparently see no response at all, which would indicate another source for the increase in the atmospheric level.

But if someone with statistics knowledge could calculate or comment on the correlation between the emissions and the atmospheric level it would be a good start.

Then we can argue over whether we expect the correlation to be excellent or just fairly close.

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