Your asserted number (1,100 GtC) seems to be a wild exaggeration: "In the period 1751 to 1900, about 12 GtC were released as CO2 to the atmosphere from burning of fossil fuels, whereas from 1901 to 2013 the figure was about 380 GtC." [1]
"From 1870 to 2014, cumulative carbon emissions totaled about 545 GtC. Emissions were partitioned among the atmosphere (approx. 230 GtC or 42%), ocean (approx. 155 GtC or 28%) and the land (approx. 160 GtC or 29%)." [2] (And 230 GtC is 843 GtCO2, so that doesn't match either.)
Your asserted number appears closer to an estimate of total GtC in the atmosphere, not merely the modern addition via human CO2 emissions. Where did that 1,100 number come from?
I tracked down one scientific paper that mentions "1,100 Gt CO2" but the context is completely different from what was being claimed (total human emissions so far): it's an estimate of the remaining global carbon budget from 2011 onwards for the political goal of limiting global temperature rise to 2 ̊C.
"A temperature rise of 2 ̊C is consistent with combustion and release of around 1 trillion tonnes of carbon (1000 Gt C). The 2013 IPCC Working Group 1 report calculates the remaining global carbon budget from 2011 onwards consistent with the political goal of limiting global temperature rise to less than 2 ̊C to be 300 Gt C, equivalent to emission of 1100 Gt CO2. Current known and exploitable fossil fuel reserves are equivalent to 3100 Gt CO2, three times greater than this cumulative emissions budget. A conservative estimate of the additional fossil carbon resource that could be extracted is 30-50 times greater (~45000 Gt CO2)." [1]
Their reference for that amount is "IPCC. Fifth Assessment Report Summary for Policymakers, Working Group 1: the physical science basis (2013)". [2] However when I read and search that document that particular number is absent. A search of the full 1,552 page report [3] also comes up empty.
[1] Scott. V., Haszeldine, R.S.H., Tett, S.F.B., Oschlies, A., Fossil fuels in a trillion tonne world, Nature Climate Change 5, 419–423, 2015. (https://www.nature.com/articles/nclimate2578)
"From 1870 to 2014, cumulative carbon emissions totaled about 545 GtC. Emissions were partitioned among the atmosphere (approx. 230 GtC or 42%), ocean (approx. 155 GtC or 28%) and the land (approx. 160 GtC or 29%)." [2] (And 230 GtC is 843 GtCO2, so that doesn't match either.)
Your asserted number appears closer to an estimate of total GtC in the atmosphere, not merely the modern addition via human CO2 emissions. Where did that 1,100 number come from?
[1] https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_at...
[2] https://www.co2.earth/global-co2-emissions