Carbon emissions are expected to grow exponentially from 5.5 Gt/yr to 21.4Gt/yr over the next 100 years. What would be the atmospheric concentration of CO2 in 100 years if the concentration is...

Carbon emissions are expected to grow exponentially from 5.5 Gt/yr to 21.4Gt/yr over the next 100 years.

What would be the atmospheric concentration of CO2 in 100 years if the concentration is presently 400ppm and the mass of C in the atmosphere is presently 848 Gt?