There has been a lot of confusion about how much future warming is "in the pipeline" today, and if its too late to avoid large amounts of warming in the future. Lets take a look at what the science says:
First, if concentrations of greenhouse gases remain at today's level (e.g. ~408ppm CO2, ~1860ppb CH4, etc.) and aerosol emissions remain unchanged, there would be around 0.5C additional warming when the system reaches equilibrium (e.g. the oceans slowly warm up).
However, for concentrations of GHGs to remain constant would require continued emissions; close to today's levels of CH4 emissions (for constant concentrations), and perhaps 15% of today's CO2 and N2O emissions (though its a bit complicated for CO2).
If we cut CO2 emissions to zero concentrations don't remain constant; rather, they decline as the oceans and land remove some of the excess CO2 from the atmosphere. 
If we bring CO2 to zero (and hold concentrations of other GHGs and aerosols constant), the decline in atmospheric CO2 nicely counteracts the warming in the pipeline, and temperatures remain fairly flat.
This isn't necessarily good news, as it means our historical CO2 emissions have locked into current levels of warming for the next few hundred years, at least in the absence of large-scale carbon removal from negative emissions technologies.
Once you start looking at greenhouse gases beyond CO2, the picture becomes even more complicated. Cutting methane emissions to zero results in a quick drop in global temperatures, as methane has a very short atmospheric lifetime compared to CO2:
N2O has a somewhat longer lifetime, but most is still gone within a century after emissions cease. It doesn't have the long tail that characterizes CO2, as it is removed from the atmosphere through chemical reactions (CO2 on the other hand has to be absorbed by land/ocean sinks)
Aerosols have both a short lifetime and a strong cooling effect; cutting them to zero while holding concentrations of everything else constant would actually bump global temperatures up by around 0.5C (with a large uncertainty).
The SR15 had a helpful (but quite complex) figure exploring all these different cases. The "zero everything" orange line shows that temperatures have a decade or so bump due to ceasing aerosol emissions, but are quickly counteracted by declining non-CO2 GHGs.
@Peters_Glen also had a useful thread on these topics a few days back:
