Ben Nevis ‘growth’ leaves me feeling peaky

http://www.theguardian.com/environment/2016/mar/21/ben-nevis-growth-leaves-me-feeling-peaky

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When it comes to the height of Ben Nevis (Bigger Ben: UK’s highest peak just got a little taller, 18 March), has the Ordnance Survey not heard of postglacial isostatic rebound since the last ice sheets melted? Compared with Newlyn in Cornwall, which is slightly sinking, the latest GPS measurements suggest a difference in Ordnance Datum of nearly 2mm a year, equating to about 12cm over 65 years.

Such heights also depend on how the modern geoid (hypothetical sea level) is computed from freely available British Geological Survey gravity data gathered without the benefit of using local OS benchmarks measured to within the nearest cm, as even decades ago this was unaffordable. Why make such a fuss over this molehill, when anyway in Germany heights on 25k maps are usually quoted to within 10cm, with more detailed contouring in flatter areas?David Nowell Fellow of the Geological Society

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