The problem with the claim is that there's a tide gauge (actually, several of them) in the San Francisco Bay basin. One of them with a 75 year record is at Alameda Naval Air Station.
It shows no material change in tidal levels.When one actually stops to compare the claim that increased global temperatures will lead to rising ocean levels to elementary school science, it becomes readily obvious that the claim is, to put it bluntly, full of shit. More precisely, the idea that higher temperatures lead to melting ice caps, which in turn leads to rising ocean levels is an extremely simplistic model that ignores some very basic and well-established scientific theories.
In the first place, it must be noted that ice (solid water) is less dense than liquid water, as evidenced by its tendency to float on water. To wit:
Things float when they are positively buoyant, or less dense than the fluid in which they are sitting. This does not mean that an object has to be lighter than the fluid, as in the case of a boat; objects just need to have a greater ratio of empty space to mass than the fluid.More to the point, pound for pound, ice takes up 9.05% more volume than its liquid counterpart. Converting liquid water into solid requires more volume; reversing the process requires less volume. Thus, melting ice caps and oceanic ice (e.g. icebergs) wouldn't necessarily increase oceanic levels at all simply because liquid water is more dense than solid water.
Moreover, it is estimated, at least in the case of icebergs, that only 10-20% of the volume of the ice sits above the water. Assuming that the visible area is closer to 10% of volume than 20%, an iceberg that melts completely would have virtually no effect on ocean levels, since the visible volume is basically the same as the difference in volume between the solid and liquid forms of water. As such, as the berg melts it would condense in volume and not cause anymore displacement.
Considering that water covers 71% of the earth's surface while only 1.7% of that volume is in solid form, it seems downright illogical to assert that such a relatively small amount of water will lead to increased oceanic levels as it condenses in volume. Granted, some solid water is on land (e.g. glaciers), but given that water condenses when it melts, it does seem remarkably ignorant to hypothesize that melting ice caps will lead to unparalleled catastrophe.
Finally, one must also account for evaporation when discussing the water cycle. If higher temperatures led to more melted ice, they would also likely lead to an increase of water vapor in the atmosphere. Per Wikipedia:
The main ways water vapor is added to the air: wind convergence into areas of upward motion; precipitation or virga falling from above; daytime heating evaporating water from the surface of oceans, water bodies, or wet land; transpiration from plants; cool or dry air moving over warmer water; and lifting air over mountains. [Emphasis added.]Ocean water evaporation is very much contingent on relative temperature:
The most noticeable pattern in the time series is the influence of seasonal temperature changes and incoming sunlight on water vapor. In the tropics, a band of extremely humid air wobbles north and south of the equator as the seasons change. This band of humidity is part of the Intertropical Convergence Zone, where the easterly trade winds from each hemisphere converge and produce near-daily thunderstorms and clouds. Farther from the equator, water vapor concentrations are high in the hemisphere experiencing summer and low in the one experiencing winter. [Emphasis added.]Obviously, if more ocean water evaporates in the summer when the temperatures are warmer, then it should make sense to assert that warmer global temperatures will generally extend and/or accelerate this cycle. If that is indeed the case, then it should also seem reasonable to assert that the evaporation cycle would ameliorate the admittedly limited effect of melting ice. Hell, for all anyone knows, the evaporation cycle might be severe enough to add so much water to the atmosphere that ocean levels recede and the coastline expands.
Anyhow, as Karl Denninger points out, the mere fact that ocean levels haven't risen in conjunction with temperature should suffice to refute the theory that global warming leads to rising ocean levels. In fact, given the basic science of the water cycle and the chemical properties of water, it seems to be a downright ignorant assertion. Perhaps it would be best to simply start ridiculing global warming scaremongers for being so ignorant about science.