[Greenbuilding] more on ice melt

Benjamin Pratt benjamin.g.pratt at gmail.com
Wed Aug 29 18:39:01 PDT 2012


However, isn't the greater volume of fresh water offset by the fact
that water expands when frozen (and shrinks when it thaws)?

On Wed, Aug 29, 2012 at 1:44 PM, Alan Abrams <alan at abramsdesignbuild.com> wrote:
> so ice cap and sea ice melt *does impact sea level....
>
> from:
>
> http://nsidc.org/news/press/20050801_floatingice.html
>
> Melting of Floating Ice Will Raise Sea Level
>
> 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.
>
> -AA
>
> Alan Abrams
> Abrams Design Build LLC
> design for purposeful living
>
> 6411 Orchard Avenue Suite 102
> Takoma Park, MD 20912
> office  301-270-NET- ZERO (301-270-6380)
> fax      301-270-1466
> cell     202-437-8583
> alan at abramsdesignbuild.com
> www.abramsdesignbuild.com
>
>
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-- 


b e n j a m i n p r a t t

professor art+design
the university of wisconsin stout



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