Reply To: Questions regarding DPF.

[Phil’s Dad]

The fraction of anthopogenic CO2 (AF = Anthopogenic Fraction) that remains in the atmosphere has been constant – not quite the same thing.

In Dr Knorr’s own words:

“Half the CO2 we emit stays in the atmosphere…”
(Roughly)

His graph is attached. The annual increase in atmospheric CO2 (as determined from ice cores, thin dotted lines, and direct measurements, thin black line) has remained constantly proportional to the annual amount of CO2 released by human activities (thick black line). The proportion is about 46% (thick dotted line). (Figure source: Knorr, 2009)

You will note that all lines in his graph are increasing

But being a simple minded fellow I like to think of these things on a human scale. Here’s how I explained it to myself.

If I could borrow Rezwan’s aircon bucket for a minute.

* Put the plug in the bath. (The bath is my analogy for the atmosphere)
* Fill a bucket (Say 2 gallons) with water (Analogy for our emitted CO2).
* Carry the full bucket up all those stairs. (Obscure reference – ignore)
* Pour half of it down the sink and the rest into the bath.
* Result 50% taken up by the sink and 50% in the bath/atmosphere. (AF=50%)
* Or 1 gallon down the sink and 1 gallon left in the bath.

* Next day, fill the bucket, climb the stairs, pour half down the sink and half into the bath.
* Result 50% taken up by the sink and 50% in the bath/atmosphere. (AF=50%)
* Or, on day two, 1 gallon down the sink and 2 gallons left in the bath. Yesterday’s gallon is still there. (ppm doubled)

The proportion of our emitted CO2 that is taken by the sink or poured into the bath/atmosphere has remained the same at 50% but the amount now in the bath/atmosphere has risen and will continue to rise as long as we go on filling/lugging buckets (emitting).

This is what the paper is saying.

Atmospheric CO2 is rising at (constantly) about half the rate we are emitting it. Whether that matters is a whole different discussion.

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