1. This work is supported by the National Science Foundation’s Transforming Undergraduate Education in STEM program within
the Directorate for Education and Human Resources (DUE-1245025).
What causes sea level to change?
Unit 2: Part 1

2. Sea level has changed a lot throughout
Earth’s history:
Modified from:
http://www.bgs.ac.uk/discoveringGeology/climateChange/general/coastal.html?src=topNav
In groups, brainstorm about processes that cause sea level to
change (you should think of at least four).

3. Processes that cause sea level to change:
http://www.grida.no/graphicslib/detail/causes-of-sea-level-rise-from-climate-change_d0cf

4. Which process do you think is currently
causing the most sea level rise?
A.Changes in terrestrial water storage
B.Subsidence in coastal regions
C.Ocean circulation changes
D.Warming ocean causing water to expand
E.Melting of glaciers and ice sheets

5. Which process do you think is currently
causing the most sea level rise?
A.Changes in terrestrial water storage
B.Subsidence in coastal regions
C.Ocean circulation changes
D.Warming ocean causing water to expand
E.Melting of glaciers and ice sheets

6. Estimated contributions vs.
observed rates of sea level rise
• Thermal expansion currently accounts for
roughly half of the observed sea level rise;
• While Greenland and Antarctica have the
potential to contribute substantial amounts
of ice (around 120m of global sea level if
they both completely melted), their current
contribution is dwarfed by small mountain
glaciers and ice caps;
• Sea level rise that is measured with
satellites and tide gauges is larger than the
sum of the components. This discrepancy
highlights the need for additional
measurements!
http://www.grida.no/graphicslib/
Author: Hugo Ahlenius, UNEP/GRID-Arendal

7. While sea level changes are global, local geologic
controls cause large differences in measurements.
http://tidesandcurrents.noaa.gov/sltrends/
We will learn
about these local
differences
throughout the
module.