I know how distraught you are over the news stories that strike fear in your young heart.
“Climate change causes the tides to rise!”, you are told. May I put your fears to rest? Do you not want to return to your Swedish playmates, hang out, watch goofy movies, and chat over Starbucks? Are there Starbucks stores in Sweden?
The threats to Venice are manifold and they don’t come from above, from atmospheric climate changes wrought by human activity.
Susceptibility to flooding is a built-in feature of Venice. How so?
- the city was built on a marsh, a lagoon
- its foundation is not rock but mud
- its buildings rest on ten million tree trunks driven into the marsh
The news media like CBS, NBC, ABC, and CNN would have you believe the tide is rising. Well, in fact, it is rising – and falling – two times each day as a function of the moon, the sun, the planet earth and their relative positions. Tides vary between high and low, neap tides and spring tides. Let’s call on the grownup scientists, genuine climate scientists, at NOAA to explain these tidal events.
Another factor governing destructive high tides in Venice is the geology upon which Venice was constructed is land subsidence. Tides are not actually rising; Venice is sinking into the mud upon which it was constructed.
Venetian land subsidence, both natural and induced by groundwater withdrawal, and northern Adriatic Sea eustacy have caused 23 cm of relative land subsidence referred to as the mean sea level over the last 100 years. This relative elevation loss has been vital for Venice’s existence, inasmuch as Venice lives in the water. After a short overview of the process during the past decades, the actual trend of relative ground-sea movement is presented by integrating high precision leveling, remote sensing measurements and tide gauge records. Geodetic and Interferometric Synthetic Aperture Radar (InSAR) data evidence the present ground stability of the central part of the lagoon, where the city of Venice is located, and slight sinking rates at the northern and southern extremities of the lagoon edges …Journal of Marine Systems, 11/1/2004 | Eustacy and land subsidence in the Venice Lagoon at the beginning of the new millennium
Is there even one piece of evidence that human activity is creating the flooding problem in Venice? To be sure, yes there is. As stated above, land subsidence is almost always a consequence of the extraction of ground water by cities and industries.
This is a phenomena common to all coastal areas. It’s happening in Norfolk, Virginia, Miami, Florida, and even my own little ole hometown of Palacios, Texas.
Prevailing winds have more to do with inland waterway apparent sea level rise. When high tide, a property facing south to oceanic waters will experience much higher tides if the prevailing wind is out of the south.
A local-to-Texas example, the flooding of Bridge City, Texas in November 2008. Storm surge ahead of Hurricane Ike pushed water from the Gulf of Mexico up to and over the normal high-tide mark in this coastal city. My wife and I can attest to the Venice-like devastation – we served on the disaster relief team of our church.
To further give you peace, Greta, just know that we old folks have lived through coastal flooding in Texas for over seventy years. Flooding, however undesirable, is a natural phenomenon. Natural means “not man-caused”.
In my lifetime, I have witnessed huge losses of private property on coastal areas. The choices are (1) move to higher ground and (2) make the ground higher. The city of Galveston, Texas made the second choice after the deadliest hurricane in Texas history took the lives of thousands of residents.
So by a ratio of 150 to 1 the people who could vote decided to undertake a wild engineering scheme. They would build a great dam, a Sea Wall along the south Gulf coast. It’d be 17 feet high and 3 miles long with a skirt of protective granite rip-rap. But the Sea Wall was a piece of cake compared to what followed. Next they raised the whole city.University of Houston, Copyright © 1988-1997 | Engines of our Ingenuity: No. 865 Raising Galveston
I know you are relieved, Greta. That’s why you are now smiling!