Bugsy, it is you who are confused; either that or you are trying to generate confusion.

Both the Knorr graph and the fianl graph are plain; the difference between them is that in the latter graph the AF is shown as 40% of total human emissions which was Knorr's calculated amount, not the 46%, which was the estimate in his graph.

Knorr's graph shows the human emissions with the top, thick, unbroken line. The last graph shows the human emissions as the top blue dotted line.

Knorr's graph shows the AF as 46% with the thick dashed line. The bottom graph shows AF at 40%, over a shorter period, as the bottom yellow dotted line.

Both Knorr and the bottom graph show atmospheric increase in CO2 from 1959 in the jagged unbroken black line.

Both Knorr and the bottom graph plainly show that the amount of human CO2 left in the atmosphere as measured by the AF, is insuffiecient to explain the increase in atmospheric CO2.

If that is confusing to you Bugsy then that is your problem because it is pretty clear to me.

It is far from clear cohenite.

The increase in total human CO2 emissions greatly exceeds that required to explain the increase in atmospheric CO2 concentrations, that much is patently clear.

What you are seem to be saying is that 40% of human emissions is not enough to explain the increase in concentration. Fair enough, you disagree with Knorr then, because that paper calculated that only 40% (or perhaps 46%) of human emissions is enough to explain the increase and that has remained constant over time, i.e. does not appear to be accelerating.

But somehow you are saying that black is white and natural sources must be invoked to explain the increase?

Weird...

"Fair enough, you disagree with Knorr then, because that paper calculated that only 40% (or perhaps 46%) of human emissions is enough to explain the increase and that has remained constant over time"

Knorr doesn't say that; the AF is the % of human emitted CO2 which stays in the atmosphere and is not absorbed by the sinks. Knorr made no connection between the AF he found and the increase in atmospheric CO2 other than comparing them in his graph; and even when you look at Knorr's estimate of a 46% AF from his graph it is plain that the increase in atmospheric CO2 is often ABOVE the AF, or the human CO2 which remains in the atmosphere.

When the correct 40% AF is plotted against the increase in atmospheric CO2, as shown in the bottom graph, it is even more plain that human CO2 cannot, as you say, "explain the increase and that has remained constant over time".

The AF only remains a constant of the increase in human CO2 emissions which are increasing, so in real terms, the AF is getting bigger; but the rate of increase of the AF is less than the rate of increase in the atmospheric CO2; so a source of CO2 other than human emissions must be supplying that increase beyond what the AF can do.

The world's air has reached what scientists call a troubling new milestone for carbon dioxide, the main global warming pollutant.

Monitoring stations across the Arctic this spring are measuring more than 400 parts per million of the heat-trapping gas in the atmosphere. The number isn't quite a surprise, because it's been rising at an accelerating pace.

Years ago, it passed the 350ppm mark that many scientists say is the highest safe level for carbon dioxide. It now stands globally at 395.

So far, only the Arctic has reached that 400 level, but the rest of the world will follow soon.

"The fact that it's 400 is significant," said Jim Butler, the global monitoring director at the National Oceanic and Atmospheric Administration's Earth System Research Lab. "It's just a reminder to everybody that we haven't fixed this, and we're still in trouble."

"The news today, that some stations have measured concentrations above 400ppm in the atmosphere, is further evidence that the world's political leaders – with a few honourable exceptions – are failing catastrophically to address the climate crisis," former vice president Al Gore, the highest-profile campaigner against global warming, said in an email. "History will not understand or forgive them."

Carbon dioxide is the chief greenhouse gas and stays in the atmosphere for 100 years. Some carbon dioxide is natural, mainly from decomposing dead plants and animals. Before the industrial age, levels were around 275 parts per million.

cohenite,

I didn't read Middleton's article. There are more articles available than I could read in the rest of my life, written by scientists who at least have the sense not to advertise themselves as being people whose interest in the science is only to point to a particular conclusion.

I certainly don't have time to read his 23 references. One, yes, 23, no. Suggestions welcome.

Re Jo Nova, I accept that she is a "graduate in molecular biology". She doesn't regard it as particularly significant in the self-promotion on her website (I think she's right - it's about as relevant as my own scientific qualifications, ie, not very). What she regards as most significant is the nice things Andrew Bolt says about her. I find that weird.

All this doesn't say that these people are wrong. But there's plenty of material to read by people who at least look like potential sources of reliable scientific information.

Actually, you are right, Knorr does not calculate the AF to be 40%, that came form somewhere else, but a bit higher than that.

You state in your opinion piece, "The constant AF found by Knorr was about 40%.", however I cannot find that in his results or conclusions, could you please point it out for me?

One of the conclusions of the paper was that emissions from land use changes was probably overestimated. Otherwise the possibility exists thats,"a larger proportion of emissions is taken up by the ocean than what has been previously assumed", which I think is what Mark was talking about. However you seem to be concluding the polar opposite of that: the oceans must be belching it out.

Nowhere, absolutely nowhere appears the indication that anthropogenic emissions cannot account for the increase in concentrations, they very clearly can. Knorr just concludes that the percentage of the emissions remaining in the atmosphere has not been increasing.

Mark reckons that it must accelerate for the 'theory' (whichever one he is referring to?) to work. I guess that is for another discussion at another time.