Pilkey began his career with the study of abyssal plains on the deep sea floor. As a result of the destruction of his parents' house in Waveland, Mississippi in Hurricane Camille (1969), he switched to the study of coasts.Better late than never, I suppose, and I'd suggest the name "Waveland" might have hinted at something earlier. Perhaps I'm being unkind, but I'm in one of those moods where my wit has a pH of 2.0 and the sarcasm fairly flies from my fingertips. I know that sarcasm's considered as the lowest form of wit, but it's fun.
Anyway, I came upon "Sea Level Rise And The World’s Beaches" on Coastal Care, penned by said (retired) Professor Emeritus of Earth and Ocean Sciences, Nicholas School of the Environment, at Duke University, Orrin H. Pilkey himself. I thought "coastal care" involved not dropping litter and following the country code "take only photographs, leave only footprints", and resisting the temptation to vandalise wind turbines, you know, that sort of stuff. You might deduce that I came upon this gem of science and logic purely by chance, and you'd be right. He begins
Of all the various anticipated impacts of global climate change, sea level rise will likely be the first to produce a human catastrophe on a global scale. Heavily populated low-lying lands on deltas (e.g., The Ganges-Brahmaputra Delta) will be abandoned, displacing millions of people. Atoll nations in the Pacific (Tuvalu) and Indian Oceans (The Maldives) will disappear; major cities (Miami, Rotterdam, New York/Newark) will be building storm gates and abandoning the low-lying city fringes. Barrier islands lined with tourist facilities and high-rise buildings along the world’s coastal plains will either be abandoned or will be completely surrounded by massive sea walls. Development-lined beaches everywhere will be degraded and more than likely will be destroyed.Rotterdam already has a "storm gate" known as the Maeslantkering, completed in 1997. It works automatically, with warnings to shipping issued a coupla hours in advance. It's worth a look - when it comes to protection from the sea, the Dutch don't piss about - they build big and to last. This gate is just the northern half of the barrier, the two gates pivot out to meet in the middle of the waterway, when water is admitted to the curved caissons so they sink to the bottom. To allow this movement, the gates are supported on huge ball-joints (nearest the camera); they're 10 metres in diameter and weigh 680 tons each.
|Northern half of the Maeslantkering Source: Geolocation|
I think the Prof might have just the teeniest chip on his shoulder about storm surge. He continues, after discussing the last ice age and the result of its termination on sea-levels
Sea level change is actually a combination of the change in the volume of the sea (eustatic change) and the local up and down movement of the land (tectonic change). The rise is primarily occurring because the ocean water is expanding (thermal expansion). As the warming atmosphere transfers heat to the surface waters of the oceans, the waters gradually expand. The upper 2000 feet of the oceans are involved in this process and even though the amount of expansion per unit volume of sea water is slight, the huge quantity of water expanding in the oceans leads to a significant increase in the volume of the sea and hence to a rise in the level of the sea.
Even if we reversed global warming today, thermal expansion of the oceans would continue for centuries and probably millennia to come. This is because the downward motion of water warmed by contact with the warming atmosphere into deeper waters provides momentum like the momentum furnished to an engine by a flywheel. As the cold deep water is thus warmed it expands. At the same time, the loss of the warm water at shallower depths causes the water column there to shrink. The expansion at depth is greater than the contraction in shallow water so overall the ocean expands and the sea level continues to rise and will do so for a long time.Wait a mo' - let me run over that again - "the downward motion of water warmed by contact with the warming atmosphere into deeper waters provides momentum like the momentum furnished to an engine by a flywheel". Silly me thought that warmed surface water expanded upwards taking it's centre of gravity with it - very slow upward motion and therefore momentum. The next sentence is convolutingly fascinating - "the loss of the warm water at shallower depths causes the water column there to shrink". The warmed water's not lost, it's still there, above the as-yet un-warmed depths. The un-warmed deeper water is unaffected - no temperature change, no volume change. The depth of the colder layer is reduced, the water there doesn't shrink. Water column 1000 metres, top 100 metres expands to 100.1 metres, bottom 900 metres is unaffected, result 1000.1-metre depth. Call for a shrink.
After some discussion of melting glaciers and icecaps - in the Prof's icy mind, all are shrinking, none growing, he says
Sea level is dropping in Juneau, Alaska, because the Mendenhall Glacier has retreated away from the coast and the land is rebounding, having been released from the glacier’s weight. This is a widespread phenomenon in high latitudes in the Northern Hemisphere (e.g., Scandinavia) where the ice sheets of the last ice age have recently (in a geologic time sense) melted away. It is also happening in Greenland and the Antarctic where the land beneath the ice rebounds upward as the weight of the thinning glaciers decreases.Ummm no. The Mendenhall Glacier has certainly retreated in the last half-century or thereabouts, but it's just 12 miles (19 km) long, and its weight isn't that great compared with the mountains it slides down, a mere pimple compared with the depth of the crust. In any case, glacial rebound is delayed by centuries after top weight is reduced, so the land rebounds centuries after "the weight of the thinning glaciers decreases". I though geologists had a good sense of the timing and delayed action of crustal processes, and of scale. The Prof obviously has some difficulty conceptualising both, not a good trait in a geologist.
After some discussion of how rapidly (who said?) rising sea levels are and will increasingly affect coastal areas, he says
The point is that a very small sea level rise will cause a large shoreline retreat. Sea level rise is not to be easily dismissed.
Yet in the December 27, 2010, issue of Forbes magazine is an article that argues sea level is not rising. Swedish geologist, Nils Axel Mörner has written a pamphlet entitled Sea Level Rise is the Greatest Lie Ever Told. These and many other expressions of skepticism about sea level rise are part of a larger deniers movement largely funded by energy companies and libertarian organizations. It’s hard to fathom how a 150-year record of tide gauges and 19 years of satellite measurements of sea level change can reasonably be refuted.The amount of shoreline retreat rather depends on the profile of that coastline surely. I certainly agree with him on that last point, though - it's certainly difficult to fathom how such records can be refuted - scope for a few future posts there perhaps.
Newton is claimed to have said or written
I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.IMHO the "great ocean of truth" is still eluding Orrin H. Pilkey (and many others, sceptics included), and he should continue his beachcombing in the hope of acquiring a little of Newton's insight, and a firmer grasp of what's beyond his experience and limited knowledge of the world and how it works. A little humility turneth away wrath perhaps, to mangle several epithets in one go. Over and out.