Update

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.

Rough Weather
A view from the porthole of the NBP main deck as we head south in rough weather.

Sea Level Rise 101

Some of the students of Brooklyn Prospect Charter School’s Environmental Science class would like to take a closer look at sea level rise.

  • “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.

SLR Tools
A NOAA buoy used to measure sea level (Photo courtesy of NOAA); a chart of sea level taken from satellite data(Picture courtesy of NASA/JPL).

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.

SLR in San Pedro
Predicted changes to sea level in San Pedro, CA. Map Courtesy of NOAA. Check their website (link below) to see predicted changes for your area.

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 predictions.

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 situations.

Explore on your own. To learn more or explore impacts in your area check some of these websites: NOAA’s Sea Level Rise Page Climate Central NASA/JPL’s Sea Level 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: Environmental Protection Agency Carbonfund Organization

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?

Date
Weather Summary
Rainy
Temperature
52 F
Wind Speed
32 mph
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Comments

Susan Steiner

great analogy!! glad the rolling is better than the pitching!! great, detailed, timely post!!

Dominique Richardson

Thanks, Susan. Unfortunately we've altered our direction a little bit so now there is a bit more pitching. I'll have more photos for
tomorrow's post.

Lucy Coleman

Dominique-
This is a fabulous description of the role of land ice vs sea ice on ocean levels. Thank you for explaining it so clearly to us readers. I hope your seas settle down a bit there.... Looking out your window makes me nauseous from here!

Lucy

Dominique Richardson

Hi Lucy! Wonderful to hear from you! The seas have settled down enough for us to get comfy before the next part of the storm reaches us this
evening. It's definitely been an exciting trip down so far. Hopefully
we'll be reaching the calm waters protected by sea ice by Friday or
Saturday. Then we can get started with the science!