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Comment by Nils-Axel Mörner on the paper just published in Nature (497: 235-238) by Faezeh et al. on the Greenland ice melting and sea level rise

Written by Nils-Axel Mörner

With very great pleasure did I consume the paper by Faezeh et al. (2013) just printed in

Nature (May 9). After a careful study of four major marine-terminating outlet glaciers,

collectively draining 22% of the Greenland Ice Sheet, they were able to estimate the annual

dynamic losses at volumes corresponding to a mean global sea level rise of 0.01–0.06 mm per

year. In 100 years this would only give a sea level rise on 1-6 mm, which is insignificant. By

applying a hypothetical future warming or 2.8 oC they increase this value to 19–30 mm rise

by year 2200 (or about 9-15 mm by year 2100). Even this value is so low that it poses no

threat what so ever to humanity.

What was it I said, I may say referring to numerous previous papers of mine, but

especially the paper on “Setting the frames of expected future sea level changes” (Mörner,

2011), where the problem of the contribution of glacial melting is specially addressed (Fig. 1).

During the Holocene Climatic Optimum with a temperature 2.5 oC higher than today, the

Greenland ice cap seems to have been of roughly the same dimensions as today. The Little Ice

Ages of the last 600 years with significantly larger glaciers had small to insignificant effects

on mean global sea level. A sea level rise of today would never stay a chance to exceed that of

the main melting phase at the end of the Last Ice Age which amounted to about 10 mm year-1

(i.e. 1.0 m in 100 years); on the contrary, it would have to be well within these frames.

Now, we can see that the present day melting of the Greenland Ice Cap provides sea level

effects that are minute to negligible and fall well within the values of about 1 mm year-1 (Fig.

1) recorded during the last 300 years (Mörner, 2004).

References

Faezeh, M.N., Vieli, A., Andersen, M.L., Joughin, I., Payne, A., Edwards, T.L., Pattyn, F. &

van de Wal, R.S.W., 2013. Future sea-level rise from Greenland’s main outlet glaciers in

a warming climate. Nature, 497, 235-238.

Mörner, N.-A., 2004. Estimating future sea level changes. Global Planetary Change, 40, 49-

54.

Mörner, N.-A., 2011. Setting the frames of expected future sea level changes. In:

Evidence-based Climate Science, D.J. Easterbrook, Ed., Chapter 6, 197-209, Elsevier.

Morner sea level values

Fig. 1. Introduction of the new values on the Greenland ice melting contribution to global sea

level by Fraezeh et al. (2013) into the figure by Mörner (2011) on rates and amplitudes of

expected future changes in sea level with the frame of physically possible changes set at 10

±1 mm year-1 or 1.0 ±0.1 m in a century, and with the observed rate of changes in the last 300

years of 1 mm year-1 or 10 cm in a century.

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