What does tthe IPCC leave out of the equations?

HOW MUCH WARMING IS THERE NOW?

Sam Carana, via Facebook

According to NOAA's calculations, we're currently at 500 CO₂e. NOAA adds: 

"Because we seek an index that is accurate, only direct forcing from these gases has been included. Model-dependent feedbacks, for example, due to water vapor and ozone depletion, are not included. Other spatially heterogeneous, short-lived, climate forcing agents, such as aerosols and tropospheric ozone, have uncertain global magnitudes and also are not included here to maintain accuracy."

https://www.esrl.noaa.gov/gmd/aggi/aggi.html

How much warming do you think there is, when including all feedbacks, indirect effects and further warming elements?

This appeared in comments

NOAA includes 5 major gases (CO₂, CH₄, N₂O, CFC-12 and CFC-11) and 15 halogenated gases (CFC-113, CCl₄, CH₃CCl₃, HCFCs 22, 141b and 142b, HFCs 134a, 152a, 23, 143a, and 125, SF₆, and halons 1211, 1301 and 2402). 

The figure of 500 CO₂e is arrived at when taking NOAA's column for total CO₂e in Table 2, which goes up to 2017, and extending this by means of a linear trend, as in attached image.