He then analysed how land elevations changed along the Italian coast due to both plate tectonics and the after-effects of the last ice age. In a paper to appear in the journal Earth and Planetary Science Letters, he concludes that geological processes pushed the land up by 1.22 metres over last two millennia, which means that the global sea level rose by 13 centimetres.
This seems to me to be making an estimate to the nearest ton and then drawing a conclusion based on that estimate to the exact ounce.
There's something wrong with this. The land would have had to have FALLEN by 1.22 meters, not risen, for his figures to be correct.