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Greenland Ice Sheet Melt

By Eco Guy 9:00am 30th November 2012
We look at reports regarding the rate of Greenland ice sheet melt.

According to recent reports (see CNN & The Australian) it appears that the speed of the Greenland ice melt has been increasing at an 'alarming' rate...

The trouble with this is that this is only a problem if:

  1. The measurements are indeed accurate enough to allow this analysis to stand, and,
  2. The melt water remains as melt water and is not taken up by other parts of the climatic system (i.e. it gets converted back to ice somewhere else) and remains in balance as a whole.

Now, look at the following:

Embracing Data 'Noise' Brings Greenland's Complex Ice Melt Into Focus

To quote:

"An enhanced approach to capturing changes on Earth's surface via satellite could provide a more accurate account of how ice sheets, river basins and other geographic areas are changing as a result of natural and human factors. In a first application, the technique revealed sharper-than-ever details about Greenland's massive ice sheet, including that the rate at which it is melting might be accelerating more slowly than predicted."

Basically a way has been found of 'cleaning up' the satellite data to give us a more accurate picture of the rate of ice melt. again to quote:

"In addition, the enhanced detail of where and how much ice melted allowed the researchers to estimate that the annual acceleration in ice loss is much lower than previous research has suggested, roughly increasing by 8 billion tons every year. Previous estimates were as high as 30 billion tons more per year."

I think you will agree that is some difference between 30 billion and 8 billion tones a year.

How much is a billion tones of water?

One 1000 litres or kg's of water is a ton, that takes up one cubic meter. Therefore a thousand by a thousand by 1 meter square of water is one million tones. Go up another 1000 meters so you have a 1000 meter by 1000 meter by 1000 meter cube and that is equal to 1 billion tones (water is heavy!).

Now the surface area of the Earth is 510 million square kilometers. So if we take the millimetre 'height' of our 1km cube (i.e. 1 million millimetres) and divide that by the Earth's surface area we get how much 1 billion tones of water increases surface height if equally spread across the planet, which is easy, its 1/510 of a millimetre or 0.0019 mm.


So 1 billion tones water EQUALS 0.0019 mm of surface height increase.


Basically, what is everybody getting so worried about???

Water freezes..

Now you can't just look at Greenland and its ice melt without considering places where the ice is freezing. Have a look the graph below of Antarctic Sea Ice Extent.

Notice something strange? Yes, the Antarctic has accumulated well over a million square kilometers of sea ice above the average. Now even if that ice was just 1cm deep (likely to be far deeper in the places where it is covered, but this makes for simple maths) then that equals 10 1km cubes of water or 10 billion tones of water...



See how utterly daft it is to consider what happens in one part of the environment without the other parts? Also this points out how important it is to have accurate measurements.

Related Content Tags: greenland, ice melt, antarctic, climate change, environment

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