It’s hard to tell from the picture but we’re going through a washing
machine, figuratively. Thankfully there’s more rolling (side to side)
than pitching (up and down) and that seems to agree with me.
Sea LevelThe level of the surface of the ocean relative to the land, halfway between high and low tide, used as a standard in calculating elevation. Rise 101
Some of the students of Brooklyn Prospect Charter School’s
Environmental Science class would like to take a closer look at sea
- “Why do we need to worry about melting?” – K. S., 11th grade
- “What happens if sea level rises?” –M. T., 11th grade
- “If ice sheets are melting and sea level is rising, how can we halt
it?” – A. W., 11th grade
- “If all the ice sheets in Antarctica melted, what would happen?” I.
T., 12th grade
- “How can you slow down ice caps from melting?” P. S., 10th grade
According to the National Oceanic at Atmospheric Association, sea level
is currently rising about 3mm per year across the world (though it is
unevenly distributed across the globe). Similar conclusions have been
independently verified by a variety of institutions. This rate of sea
level rise is significantly faster than it has been over the past
century and the rate is still increasing. Scientists predict that sea
level rise could rise up to 6 feet by the end of the century.
How do we know sea level is rising?
Scientists use tide gauges around the world to track the height of
water level for a long period of time to obtain average sea level.
Scientists also use satellites to measure sea level from space. The
satellites bounce microwave pulses off the ocean surface to determine sea level height accurately within a few centimeters.
Why is sea level rising?
Two main mechanisms contribute to rising sea level: melting of major
stores of land ice, like ice sheets, and thermal expansion.
As the average global temperature increases, glaciers and ice sheets
are melting at an unprecedented rate. Although sea ice already in the
ocean does not impact sea level, land ice does. When melt water from ice
sheets and glaciers runs off the land into the ocean it increases the
total volume of ocean water, causing the sea level to rise.
Fresh melt water is generally warmer than the surrounding ocean water.
And, as global temperature increases, ocean temperature increases as
well. Warmer ocean water undergoes Thermal Expansion—when the volume
of the ocean increases due to heat. The same amount of water will take
up more space when warm than it does when it is cold, further increasing
sea level rise.
Why is sea level rise a problem?
Higher sea level threatens coastal cities and island nations with the
risk of flooding, strong storm surges, coastal damage and contamination
of fresh drinking water sources. A rise of “6 feet” doesn’t mean that
the beach will move inland 6 feet. As sea level rises 6 feet directly
upward, the ocean could move inward much farther, depending on the
topography of an area. This is why sea level rise will impact some
areas, particularly low lying coastal areas, more than others. If sea
level rise continues as predicted, some low, island countries--like the
Maldives—and coastal cities—like Miami--could be entirely underwater.
How does studying ice stream dynamics help?
Because melting ice sheets on land, like the East Antarctic Ice Sheet,
and glaciers like those in Antarctica, directly affect sea level rise
it’s important to know more about them. East Antarctica contains enough
ice to raise sea level 11 feet if it were to all melt. It’s important
for us to know how fast this ice sheet is melting to know how it will
contribute to sea level rise. By studying ice sheets and glaciers, we
can learn about how much water they contain and how fast they are
melting. These values are important in allowing scientists to predict
how much sea level will change over a given period of time.
Studying ice stream dynamics, like we are doing on this research trip,
will help scientists determine which glaciers in East Antarctica are
under the greatest threat from melting and how fast they are melting to
create more up-to-date and accurate global sea level rise models and
What can we do?
Sea level is already rising. However, with effort, we can slow the rate
of rise and with ingenuity we can mitigate the impacts of sea level
rise. We need to do what we can now, but we will also need scientists
and engineers in the future to help us adapt to new and changing global
Explore on your own. To learn more or explore impacts in your area
check some of these websites:
NOAA’s Sea LevelThe level of the surface of the ocean relative to the land, halfway between high and low tide, used as a standard in calculating elevation. Rise Page
ClimateThe average weather over a particular region of the Earth. Climate originates in recurring weather phenomenon that result from specific types of atmospheric circulation. Central
NASA/JPL’s Sea LevelThe level of the surface of the ocean relative to the land, halfway between high and low tide, used as a standard in calculating elevation. Rise Page
Make a change. Even small changes, like walking instead of driving or
turning off the lights, can really impact how much carbon emissions you
produce, which ultimately impact global climate and sea level rise. For
more suggestions on how to reduce your carbon footprint, check out the:
Try it at home
Sea Ice vs. Land Ice Experiment. With this simple experiment you can
see how sea ice and land ice are different in how they affect sea level.
Sea Ice: Fill a clear plastic cup halfway with water and add a small
handful of ice cubes. Mark the water level with a permanent maker on the
cup and measure. Return when the ice has melted and check the water
level. Re-measure and record your results.
Land Ice: Place a smaller cup upside down in a clear plastic cup. The
small cup should completely fit upside-down in the larger cup. Fill the
large cup about halfway with water, but be sure the water does not cover
the bottom of the smaller cup. Place a small handful of ice cubes on the
smaller cup, out of the water. Mark the water level with permanent
marker on the large cup. Return when the ice has melted into the large
cup and check the water level. Re-measure and record your results.
What did you observe?