[gus_massa]

The second graph is evidently curved, but it can be fitted quite good by a parabola. Crappy fit: https://imgur.com/a/ViBR21p

Why do you think it is an exponential function?

[dwaltrip]

Exponential or parabolic, the rise is still accelerating. The second derivate of sea level is positive in either case.

[gus_massa]

Yep, like .2 mm/y^2. Exponentials grow much faster than parabolas. When you see that an exponential changes from almost 0 to something, it will change from something to too big to fit in the graph soon, really soon. Parabolas grow more smoothly. The difference is important to make some realistic predictions.