IDS 102 Sea-level Changes

Each day the level of the oceans varies with tidal forces and storms, however these variations do not create long-term changes in the level of the ocean. One of the hypothesized long-term effects of global warming is that the level of the oceans will rise and flood coastlines around the world.

From observations around the world it appears that the rate of global sea-level rise is between 1.0 mm/yr and 2.4 mm/yr. Convert these rates into feet/century. (2.54 cm = 1 inch)

Although we cannot perceive this change, the land in some places around the world is sinking due to the weight of sediment pushing the Earth’s crust downward. For a moment, assume that global sea level is not changing. If you made sea-level observations at a specific location over time, how would the sea level appear to change if the land is sinking?

The opposite trend would happen if the land were uplifting due to tectonic forces (forces that build mountains). Now, let’s be real—the ocean level is not static due to melting ice masses and in some places the land is sinking and some other places the land is uplifting. How can we determine whether a specific geographic location is sinking or uplifting using this type of data? (Your answer should be specific about the rates of sea level change).

Check with an instructor before continuing.

On the other side of this page are sea level graphs of three places. Determine the rate of sea-level rise (a negative number would indicate a drop in sea level) from the graphs in units of mm/yr. Also determine if the location is stable, sinking, or uplifting. Site A:

Site B:

Site C: