The news tells us that global carbon emissions are now more or less constant, as in the 2014-16 data points of Global carbon emissions flatline continues. On the other hand, the Keeling graph of mean global CO2 keeps climbing upwards. So clearly there is some feedback which continues to put CO2 into the atmosphere, for at least 3 years after the emissions plateau. What is the source of this feedback? Is it one dominant process or a multitude of lesser feedbacks?
There's no discrepancy here. The first graph (total emissions from fossil fuels and industry; Fig. 4a of Le Quéré et al, 2016) is an input to the system, and the second graph is a proxy for the amount stored in one part of the system (the atmosphere). For the latter, it probably makes more sense to look at the total atmospheric growth rate (Fig. 4c of Le Quéré et al), which has remained positive for decades.
Note that when you add in emissions from land-use it's likely that the total emissions have continued to increase. But that doesn't detract from the main point here: if you keep putting stuff in the bucket, the amount in the bucket will continue to increase. You don't need to invoke any feedbacks for that to happen.
Atmospheric CO2 rises because more CO2 is being put into the atmosphere than is being taken out. The airborne fraction (the proportion of cumulative carbon dioxide emissions from anthropogenic sources that remains in the atmosphere) is about 50%, suggesting that total natural uptake currently exceeds total natural emissions by about half of annual anthropogenic emissions (i.e. about 5GTC per year). Thus if we keep emitting at a constant rate of 10GTC per year, then atmospheric CO2 will initially carry on rising by about 5GTC per year, which explains what we see in the second graph, because we will still be emitting more than the natural environment is able to sequester.
Unfortunately, the net natural sink depends on the disequilibrium of CO2 between the atmosphere and the surface ocean (vaguely similar arguments also apply to the terrestrial biosphere), so if we keep emissions constant, then the disequilibrium will be reduced slightly (as the surface ocean absorbs more CO2 than it emits) and so net uptake will start to fall and the airborne fraction will start to rise, however this will take time.
It is a bit like putting your foot on the accelerator (gas) in your car. If you put increasing pressure on the pedal, your car will accelerate. If you keep it in the same position, you will stop accelerating, but you won't stop moving.