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Antarctic Ice Loss The Scary Numbers

Is Antarctica getting warmer and gaining ice? | Environment | guardian.co.uk

Scientists have also used satellite observations of the land-based ice sheet to measure whether the Antarctic ice sheet has been losing or gaining ice.

Attempts to answer the question came up with estimates ranging from an increase of about 100bn tonnes of ice per year since the 1960s to a loss of 200bn tonnes a year over the same period. However, more recent reports agree that the ice sheet is losing ice – and indeed that the rate of loss has been speeding up.

The Antarctic Ice Cap contains about 85% of the world’s ice, which is about 80% of all the fresh water on earth. That ice weights about 24.5 million billion tonnes).

Assuming the higher figure of loss that is an annual loss of 200/24,500,000* 100 = 0.008% - we are lucky their measurements are so precise.

8 thousands of 1% - or are my maths wrong?

Comments

No. Maths looks OK.

My data source was:

http://www.johnstonsarchive.net/environment/waterworld.html

There they split the total Antarctic ice into floating and grounded - floating presumably will make little impact on sea level and I have ignored.
All the "grounded" was (unlike Gaul*) all divided into 4 parts:

East Antarctic Ice Sheet
West Antarctic Ice Sheet
Antarctic Cap
Continental Glaciers.

The ratio of ice volumes was: 23 : 3 : 0.2 : 0.05. Thus, only the East and West Antarctic Ice Sheet were important. All four areas were included below.

Volume was expressed in km^3.

Total volume of the 4 grounded areas was 26.3 10^6 km^3 (26,277,000 km^3)

Density of ice (from Kaye and Laby) 0.92 g/ml or 0.92 tonne/m^3

1 km^3 = 1000 * 1000 * 1000 m^3.

Hence, mass of grounded ice = 26.3*10^6 km^3 * 10^9 m^3/km^3 * 0.92 tonne/m^3

Answer: 24.2*10^15 tonnes (or 24.2 million billion tonnes).

Using your figure for annual ice loss gives a %age figure close to yourself and definitely not out by multiple factors of 10.

QED

(*Caesar divides Gaul into only 3 parts - Caesar's Gallic Wars. I did Latin at O Level!)

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