Saturday, August 7, 2010

Sea Levels Rise!

Read on CNN a
story that a giant ice block has broken off Greenland and fallen into the arctic sea. This will cause the sea to rise, just like adding an ice cube to your drink causes the level of the water to rise.

This is different then sea ice melting -- that does not cause the level of the waters to rise, just like an ice cube already in your drink does not cause the water level to rise higher....

Thought it would be interesting to actually calculate the height the sea will rise from this particular chunk of ice.


First, the facts from the story:
The ice is 260 square-km (100 square miles). For comparison, our Kent county is 872 square miles. I usually encircle a 100 square mile area on my drive into and home from work each day.

The ice is "about half the height of the empire state building" which is 381 meters (1250 feet) tall, so we will be generous and say the ice is 200 meters tall.

Volume = Area * Height = [260 km² * (1000² m²/km²)][200 m] = 52 billion square meters of water. 1 cubic meter is 264 gallons, so 52*264 is nearly 14 trillion gallons. For comparison, at 100 gallons of water per day (unfortantely this is the lowest I could find for average American usage) this is 14,000,000,000,000 gal/ 100 gal per person per day/365 days per year/300,000,000 Americans = 1.27 years worth of fresh water. It would probably last us much less time. The article suggested 120 days -- which we would get if we assumed we used 388 gallons a day, or if the block was only around 100 meters high.

Anyway, the real question is how many beach houses will be flooded now... so lets continue.
The area of the oceans is roughly 335,258,000 square km. if we assume that the 90% of the ice block is in the water, and that the displaced water spreads itself out uniformily over the entire earth, and we assume the water level is a rectangular prism (volume = area*height) instead of the more difficult spherical shell (volume = 4/3π(R³-r³)), .. blah blah blah...
(.90)(52 billion km³)/(335,258,000 km² * 1000² m²/km²) = 0.000139 meters

That's the projected rise in sea levels. Granted, this is an over-estimate because the more accurate spherical shell calculations would be lower.

0.000139 m is a tenth of a millimeter, the width of the fattest crustiest piece of hair you can find.

That's like, really small.

No need to cancel your spring break Panama City plans.

Some might think I put this up to prove sarcastically that global warming isn't occurring, or is nothing to worry about -- that was not the intention at all. In fact, those who know me more closely would know the hesitation I had in putting this up in the first place because of that very reason. While I am hesitant to sell my beachfront property -- I do think caring for the environment is an important priority that we should not just shrug off as "God's job". If I remember correctly, it was one of the first things God asked us to do?

1 comment:

  1. Love the "warning: math content". :) I love how your mind works and the calculations you compute. I also like the comparisons you included to make the quantities comprehensible. Wow I used a lot of "k" sounding words in this komment...


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