Piece by bloody piece he dismembers what has before now passed for evaluation of what is happening and can be expected to happen to sea level in a CO2-enhanced world. Such predictions have taken on hysterical proportions and been warped into worse than worst case scenarios. Almost predictably because of what so frequently proves to be the case concerning the potential for climate apocalypse, Daly finds that what undermines such fears and scenarios are the very datasets used to produce them in this instance, records from tide gauges. Just as temperature data is affected by urban heat islands, tide gauges located at major cities or ports also are subject to urbanization mainly the tendency of large cities to subside due to the weight of the structures and changes in the underground water table. This is a creeping effect that, over time, will manifest itself at a tide gauge as a rise in relative sea level.
Cities located on alluvial, low-lying coasts are the most affected.
There are a host of other problems. Tide gauges often are mounted on manmade structures that subside over time. There is even a problem related to the disappearance of the massive ice sheets that once covered large areas of the Northern Hemisphere, to which the earth s crust is still rebounding from atop earth s plastic mantle. Outside that basin, tide records are inconsistent with what is observed within it. And what is outside the North Atlantic Basin are most of the world s oceans.