How can Greenland lose 269b tons/year and loose only 269km3?

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Discussion Overview

The discussion revolves around the discrepancy between the reported loss of 269 billion tons of ice from Greenland and the corresponding volume of 269 km³. Participants are examining the calculations related to ice density and volume, as well as the sources of the numerical values provided.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant calculates the volume of ice corresponding to 269 billion tons using a density of 920 kg/m³, arriving at a volume greater than 269 km³.
  • Another participant questions the units of the mass figures, asking whether they refer to tons, long tons, or metric tons, and notes that glacier ice density can vary with depth and temperature.
  • A participant points out a potential error in the volume calculation, emphasizing the conversion between cubic meters and cubic kilometers.
  • There is a request for clarification on the source of the original mass and volume figures, questioning whether the mass was derived from volume or measured independently.
  • One participant reiterates the volume calculation, converting cubic meters to cubic kilometers and confirming the earlier volume estimate.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the accuracy of the original figures and the calculations presented. Multiple competing views remain about the interpretation of the data and the calculations involved.

Contextual Notes

There are limitations regarding the assumptions made about ice density and the definitions of the units used for mass. The discussion does not resolve these uncertainties.

IvicaPhysics
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The density of ice is 920 kg/m3.
Now let's calculate.
m = 269 000 000 000 000 kg
p = 920 kg/m3
-----------------------------
v=?
V=m/p
V=269 000 000 000 000 kg / 920 kg/m3
V = 292 391 304 347 m3 = 292 391 304.347 km3
v > 269 km3
*NOTE* I made a mistake in the title. I meant to write 269 km3
[Note: Title fixed by moderator]
 
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IvicaPhysics said:
V = 292 391 304 347 m3 = 292 391 304.347 km3
There's your problem. If 1 km = 1000 m, then 1 km3 = (1000 m)3 = 1 000 000 000 m3.
 
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It would be interesting to know the source of the original two numbers. For example was the mass calculated from the volume anyway or was the mass measured independently by gravitational survey?
 
IvicaPhysics said:
V = 292 391 304 347 m3 = 292 391 304.347 km3
v > 269 km3

As DrClaude said, 1 km3 = (1,000m)3=1,0003m3=109 m3
or
1m3 = (0.001km)3=0.0013km3=10-9km3
so
V = 292 391 304 347 m3 x 10-9km3/m3= 292. 391 km3