- Average yearly retreat of the Himalayan glaciers: In 2006, 30 metres;
- Rate at which Gangotri is melting per year: 28.1 m
- Gangotri Length: approx 30 km;
- Year in which Gangotri will disappear: 2050, if glacier melt continues at the same rate.(emphasis mine)
Friday, December 4, 2009
Innumeracy
I happened upon an article discussing glacial retreat and ice melt. At the end of the article there were several ‘glacial facts’. Here are some:
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7 comments:
Yep, frustrating.
Of course, glaciers don't melt only from the end, they also melt from the top. Possibly the constant rate referred to in the last bullet is referring to something proportional to the surface area of the glacier. As the glacier gets thinner, the linear rate of retreat will increase.
Perhaps the article meant "if the melting rate continues to increase at the same rate". Or perhaps the newspapermen just can't do math.
the newspaperman is just reading stuff propagating from a typo. Some years ago, someone typo'ed "2350" into "2035" and it's taken on a life of its own.
Jrm, it's not a linear approximation, it's exponential, each year there's less and less, that rate is proportional to the actual size, next year it will be smaller and the melting rate will be larger, next time get your facts right.
Ana: I'll grant you that it may be exponential, but the article said “if glacier melt continues at the same rate” Regardless of what is actually going on, the article as written does not make sense.
But the rate may be referring to the volume that melts or something like that. It's also quite possible that some of the numbers are approximations, e.g. the length could very well not be adapted to the ground formations underneath whereas the yearly retreat (being of much smaller scale) might be.
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