>Ocean acidification just "feels" like much sounder science to me because the effects are so much more visible, but I'm not certain about our ability to measure pH so precisely for decades either.

One additional caveat specific to ocean (or other large scale systems) property measurement is that, because of the scale, your data can be easily biased because your sensors are not uniformly or even globally deployed. That's increasingly less of a problem in earth science but for geologic data, both in time and space, we are quite liberal in interpolating/extrapolating based on very impactful and sometimes shakey assumptions. This is dangerous because it is very easy for bias from dogma to sneak in unintentionally and undetectably to produce results which may be far removed from truth.