26

Sea level has a strong seasonal signal. The annual variability is less than the daily changes associated with tidal forcing in most locations, but still can be on the order of 5-10 cm (maximum values about 15 cm). The causes of the seasonal fluctuations are mostly associated with seasonal changes in wind intensity and patterns, changes in temperature that ...


20

Earth's radius is about 6400 kilometres. That's 6400000 metres. Let's say that you have a mound 20 metres high, burying an older settlement. Your new "radius" is now 6400020 metres. Let's say that $g = 9.8\ \rm m/s^2$ at 6400, your new gravity will be $g = 9.799939\ \rm m/s^2$. Clearly, this is hardly "lower level of gravity". To make this even less ...


6

Tectonic activity can change the volume of oceanic basins and hence, modify the sea level, ice not involved. Firstly let's explain the left picture. At Cretaceous the tectonic activity was high. The flux of material from mantle to ocean ridges and plateaux reduced the volume of ocean basins, wich produced a global high sea-level observed in differents ...


5

You could try building one using a global Digital Elevation Model. There are several freely available like TanDEM-X, SRTM, or ASTER GDEM. You'd have to look for all the pixels containing a negative value. Adjacent negative pixels would give you connected regions below sea level, and you could easily estimate their area just by multiplying the number of ...


5

A paper about this was published yesterday in Nature Climate Change: Sandy coastlines under threat of erosion (Vousdoukas et al. 2020). While shoreline change can be the combined result of a wide range of potentially erosive or accretive factors, there is a clear cause and effect relationship between increasing sea levels and shoreline retreat, pointing ...


5

As a prescript, your question is firmly within the field of Glacio-Isostatic Adjustment (GIA) modeling of the Earth and the sea level. The main scientific names doing research in this direction are Jerry Mitrovica, W.R. Peltier, Roblyn Kendall, Glenn Milne, Kurt Lambeck, Giorgio Spada, and probably some more that I'm forgetting. It all comes down to, ...


5

To address your original concern, no, the fact that there are buildings underground does NOT mean that the surface of the earth is higher than in the past. What is actually happening is that these buildings are subsiding into the ground. How? Believe it or not, earthworms. Worms were once constantly tunneling through the soil underneath ancient buildings, ...


2

In the Arctic there is mostly floating sea ice and the mass of this does not change the sea level. When snow falls on the floating sea ice the weight of the snow is the same as the weight of the sea water it displaces so there will not be any change in sea level from this. But the snow falling on land during winter is water temporary removed from the sea, ...


2

SLR is thought to be caused by temperature rise, which is caused by CO2 rise and other factors. Temperature has been rising since before 1850. It could be another Question: "Why temperature does not correspond with CO2 levels since 1850". The reconstructions used, in order from oldest to most recent publication are: (dark blue 1000-1991): The ...


2

The jaguar is a close relative of the Asiatic leopard and must have had a common ancestor within the last 5 million years. The South American tapir is obviously closely related to the Malayan tapir and must also have had a common ancestor within he last 5 million years. While the first statement is more or less correct, the latter is not. The Asian and ...


1

This is no an answer per se, just a back-of-the-envelope calculation for fun. Lifting 1 kg (one litre) of water up a height of 1 meter uses 9.8 (let's say 10) joules of energy. Let's say you want to lower the sea level by 1 meter. You need to pump 3.6e17 litres (3.6e14 m2 of ocean area = 3.6e14 m3 to pump * 1000 for litre conversion). Let's say you want ...


1

During glaciations, the shelves down to ~100m depth would have been above sea level, but they would have been covered by ice sheets. Geology.com The actual "ocean floor" would still be deep water. There is a general explanation of the oil formation here and here, although they don't say when (or where the continents were when the sediments were deposited), ...


1

Arkaia's answer gives good information on the primary cause, which is the multitude of different astronomical changes that operate on various different timescales. However, there's an additional consideration, which is "storm surge" or, more colloquially, "what the weather is doing". Differences in atmospheric pressure between different areas can lead to ...


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