Melting of Floating Ice Will Raise Sea Level

Aug 04, 2005

When ice on land slides into the ocean, it displaces ocean water and causes sea level to rise. People believe that when this floating ice melts, water level doesn’t rise an additional amount because the freshwater ice displaces the same volume of water as it would contribute once it melts. Similarly, people also think that when ocean water freezes to form sea ice and then melts, the water is merely going through a change of state, so it won’t affect sea level. However, in a visit to NSIDC in May, Dr. Peter Noerdlinger, a professor at St. Mary’s University in Nova Scotia, Canada, suggested otherwise.

In a paper titled "The Melting of Floating Ice will Raise the Ocean Level" submitted to Geophysical Journal International, Noerdlinger demonstrates that melt water from sea ice and floating ice shelves could add 2.6% more water to the ocean than the water displaced by the ice, or the equivalent of approximately 4 centimeters (1.57 inches) of sea-level rise.

The common misconception that floating ice won’t increase sea level when it melts occurs because the difference in density between fresh water and salt water is not taken into consideration. Archimedes’ Principle states that an object immersed in a fluid is buoyed up by a force equal to the weight of the fluid it displaces. However, Noerdlinger notes that because freshwater is not as dense as saltwater, freshwater actually has greater volume than an equivalent weight of saltwater. Thus, when freshwater ice melts in the ocean, it contributes a greater volume of melt water than it originally displaced.

float_1


Figure 1: A freshwater ice cube floats in a beaker of concentrated saltwater. Note that the ice cube floats much higher in the saltwater than it would in a glass of freshwater because saltwater has a greater density.

float_2


Figure 2: When the freshwater ice melts, it raises the water level. Freshwater is not as dense as saltwater; so the floating ice cube displaced less volume than it contributed once it melted.


Noerdlinger's collaborator, Professor Kay R. Brower, of the New Mexico Institute of Technology, Socorro, validated the effect experimentally as seen in Figures 1 and 2.

Source: University of Colorado Boulder

Explore further: Space sex geckos at risk as Russia loses control of satellite

add to favorites email to friend print save as pdf

Related Stories

Verizon launches rewards program with tracking

12 minutes ago

Verizon Wireless is launching a nationwide loyalty program this week for its 100-million-plus subscribers. There's a twist, though: To earn points for every dollar spent, subscribers must consent to have their movements tracked ...

Technology tracks the elusive Nightjar

17 minutes ago

(Phys.org) —Bioacoustic recorders could provide us with vital additional information to help us protect rare and endangered birds such as the European nightjar, new research has shown.

Essential oils may provide good source of food preservation

37 minutes ago

A new study in the Journal of Food Science, published by the Institute of Food Technologists (IFT), found that essential oils may be able to be used as food preservatives in packaging to help extend the shelf-life of foo ...

Recommended for you

Satellite galaxies put astronomers in a spin

8 hours ago

An international team of researchers, led by astronomers at the Observatoire Astronomique de Strasbourg (CNRS/Université de Strasbourg), has studied 380 galaxies and shown that their small satellite galaxies almost always ...

Video: The diversity of habitable zones and the planets

8 hours ago

The field of exoplanets has rapidly expanded from the exclusivity of exoplanet detection to include exoplanet characterization. A key step towards this characterization is the determination of which planets occupy the Habitable ...

User comments : 0