I feel optimistic, however. We are on the cusp of really efficient solar panels and excellent batteries that will finally make it practical to power homes and offices from sunlight most of the time.
Electric vehicles are ramping up and it's very likely that in 20 years, the average passenger car on the road will be electric, or at least plug-in hybrid with 100 mpg or better.
Ultimately, we'll stop burning so much stuff. Will it be too late, or will the relatively sudden dropoff in CO2 production affect the PPM? Should be interesting to watch, for those of us who live long enough.