This looked wrong straight-away. Checking seems to confirm this. Looking at wikipedia (https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_atmosphere) 1ppm of C02 is approx. 8Gt of CO2 (other sites have slightly different figures but doesn't make much difference).
Saying pre-industrial was 280 ppm CO2 and so increase in C02 since pre-industrial is (410 - 280) =130ppm which gives a figure of approx. 1040 Gt of CO2 added. This means above quote is out by approx a factor of 3. Is this just a confusion between mass of CO2 and Carbon on it's own? If so, where is the error introduced - is it just a typo in to above quote and it should be "pull down around 200 gigatonnes of carbon"?
I don't know enough in this area to comment on the process, but you raise a pet peeve of mine. Unless we refer back to actual scientific papers, it seems we are chasing moving goalposts. Even then, it can be very difficult to make sure you are comparing apples to apples.
- Is it tons of carbon or tons of CO
2?
- What is the baseline year for temperature increases? (deg. C or F? Arrrgh!)
- Where on the persistence curve do you select the relative power of a GHG?
And in this case, the numbers look odd but when percentages are stated, do these numbers reflect that the ocean and other processes absorb ~50% of the CO
2 emitted? (NOAA)
BTW, I know I have seen numbers much much higher for ocean absorption (IIRC ~90%), which I think is confusion between CO
2 and heat.
The media is doing a terrible job. Some of it I suspect is intentional, but I think most of it is sloppiness or ignorance, and often there is no way to get back to the original paper.