Melting Icebergs Don’t Cause the Sea Level to Rise
May 26, 2017 at 12:00 pm Stephanie Wolek 9 comments
Even among people who understand that the sea level is rising due to climate change, there are still some misconceptions floating around. It makes sense that as the temperature rises, floating sea ice would begin to melt, adding extra water and raising the sea level. In reality, that’s not quite how it works and sea ice is the least of our worries.
Sea ice is melting and we’re losing icebergs that have existed for millions of years. This doesn’t cause the sea level to rise, however, because the volume of this floating ice has already been accounted for. The ice was already displacing the water and as it melts, it simply adds the same volume in a liquid form. Put a bunch of ice cubes in a full glass of water and the glass won’t overfill from the ice melting.
If floating sea ice isn’t to blame for our rising sea level, what’s the cause? As water warms up, it expands—an oddity specific to water molecules due to weak chemical bonds that can be easily broken with a bit of energy. Until water reaches its boiling point and beings to evaporate, it’ll always expand. The only other time water expands is right as it freezes and this effect only lasts during a very specific temperature range (water really is a strange molecule).
Seawater expansion isn’t the only reason for rising sea levels; land ice is also to blame. Although floating glaciers don’t cause much of a problem when they begin melting, land ice is a different story. Terrestrial glaciers and ice sheets, generally found in mountains and valleys, really do add extra water to the sea as they melt. This is a huge problem because our glaciers are currently melting very quickly. Glacier National Park in Montana contained approximately 150 glaciers. Modern estimates based on a large number of studies show that by 2030, the park might not have any glaciers left. Currently, less than 30 glaciers remain in the park. Although a dramatic example, this melting isn’t limited to any specific part of the planet. Terrestrial ice is melting everywhere and this adds a ton of water to our oceans—leading to both a rising sea level and changes in water chemistry that can negatively affect marine life.
As greenhouse gases continue to trap heat, warming our planet’s climate, seawater expands and the sea level rises. The melting of floating icebergs doesn’t matter much in this scenario but terrestrial ice sheets and glaciers sure do. These sheets of land ice add extra water to our ocean, leading to sea level rise and changes in water chemistry.
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Image: TomaB (cc)
Sources: umaine.edu, nasa.gov, noaa.gov, nationalgeographic.com, nasa.gov
Entry filed under: Be Green. Tags: climate change, global warming, icebergs, sea level.
Broken Secrets 
1.
Newton Snookers | May 26, 2017 at 6:23 pm
Your article is confusing to the lay person. You are correct that floating sea ice will yield no net change in the sea level. However, the vast majority of water ice on earth is not on the sea and by melting it off of land, that WILL generate a dramatic net increase in sea level. If the Antarctic ice melts from that continent, the sea level increase will be unbelievable.
2.
Blake | August 5, 2017 at 8:05 pm
It actually says pretty much that exact thing in the article.
3.
Brendt | July 5, 2017 at 12:52 pm
I think you mean to say “begins to evaporate,” when you say “beings to evaporate.” Unless there are beings involved in evaporation, which would be pretty amazing.
4.
UnPierrot | August 3, 2017 at 8:18 am
Sea floor rise and deep volcano add volume too.
5.
Earl Desuba | October 29, 2017 at 12:23 pm
Land subsidence is also a factor.
Not all of the volume of floating ice has been accounted for. Pressing down on an ice cube causes the waterline to rise.
6.
Earl Desuba | October 29, 2017 at 12:41 pm
Also land erosion. Mountains being washed down streams and rivers then dumbed into to sea.
7.
Mr | December 10, 2017 at 8:06 am
“we’re losing icebergs that have existed for millions of years.”
There are no million year old icebergs. Perhaps you meant glaciers?
8.
Peter Hill | October 7, 2018 at 3:54 pm
Icebergs have, in fact, been around for millions of years – but not the same ones!
9.
Ice | February 7, 2019 at 12:30 am
If you need to melt snow and ice off your sidewalks and driveway, be sure to use products that don’t use caustic or hazardous ingredients. There are safe and effective ice melt products that won’t irritate sensitive skin or foot pads.