snout of glacier

31 Jul 2016

In Down to Earth 96 (August 2016, ISSN 0969 3408), we have an article by geologist Brian Ellis who has been looking at records and visiting the site of a glacier that once filled the Nigard Valley in Norway, one of the outflows from the major Jostedal ice cap north of Sogn fiord. It goes back to the Little Ice Age and concerns documents of landowners complaining that tenant farmers had not paid their rent and court records from the same farmers who complain their farm is being overcome by advancing glaciers. In 1684 two farmers taken to court had as their defence they could not pay the rent because their high pastures were covered in ice. Later records show the ice was advancing across the valley floor bottom and Mjolver farm was in danger. This farm was located at the head of the Nigard valley which means the snout of the glacier had advanced right the way down. In 1738 the farm was abandoned as the growing glacier had swallowed up most of the meadows (and the cold blowing off the glacier prevented cereals from ripening, and eventually, from growing altogether). Between 1710 and 1735 the snout of the glacier advanced by 2800m (just over 100m per year). In 1742 officials found the glacier across the entire valley and in 1743 it carried away the farm buildings with a great mass of soil, grit and giant rocks (and these eventually formed a terminal moraine in around 1750). The ice advance between 1684 and 1750 was at an average rate of 50m a year, the Nigard valley being 3500m in length.

The glacier subsequently retreated and in so doing doing created several recessional stadial moraines (in between moraines) which have been have been well studied and dated. Between 1750 and the late 1930s the glacier first moved up the valley about 2000m at an average rate of almost 11m a year (a fairly slow process) but between 1935 and 1964 it moved back by another 1800m giving an average of 70m a year (and most of this fall back is now occupied by a lake). There has been further retreat since 1964 but monitoring by Norwegian glaciologists during the 1980s and 1990s show the ice front if advancing in some years and retreating in others which is just when the global warming scaremongering took off (and the retreat should have been obvious). More importantly, the evidence shows that ice growth and ice retreat can speed up or slow down as it has done over the last 300 years. You may also wonder why climate scientists like to go back to the Little Ice Age with their modelling and those weighted graphs that show an upward warming trend - right out of the Little Ice Age (or you may not wonder and be cynical enough to think it is purposely designed that way to pull the wool over the eyes of Joe Public - or those gullible enough to be taken in by the spin). It is no accident that the most rapid rate of retreat occurred in the 1930s, and just after, when temperatures were at their highest since the Little Ice Age (subsequently air brushed out of the graphsand the models as it didn't fit into the narrative). Amazing what a little tweaking of the data can do.

At http://Londonpavementgeology.co.uk ... we have an interesting site, the brainchild of a retired oil company executive, which purports to show where central London paving slabs were quarried (street by street). It is a work in progress.