Arctic Ice Loss and The AMO
By Paul Homewood
Shock news! Scientists discover natural climate cycles.
From the Mail:
The Arctic icecap is shrinking – but it’s not all our fault, a major study of the polar region has found.
At least half of the disappearance is down to natural processes, and not the fault of man made warming.
Part of the decline in ice cover is due to ‘random’ and ‘chaotic’ natural changes in air currents, researchers said.
The study, separating man-made from natural influences in the Arctic atmospheric circulation, said that a decades-long natural warming of the Arctic climate might be tied to shifts as far away as the tropical Pacific Ocean.
Astonishingly though, the study makes no mention of the Atlantic Multidecadal Oscillation, which also has a significant effect on Arctic sea ice extent.
Since the late 1970s, the AMO has moved from the coldest point of its cycle to its highest, coinciding with a decline in Arctic sea ice coverage.
On the previous occasion when the AMO cycled from cold to warm, between the 1920s and 1950s, there was also dramatic warming in the Arctic and reduction of sea ice. It even had a name, “The Warming in the North”.
As early as 1922, its effects were already being noted:
HH Lamb reported that Arctic sea ice declined by between 10 and 20 per cent between 1920 and the late 1930s.
HH Lamb: Climate, History and the Modern World – p260
And the effect of the AMO on land temperatures was unmistakeable.
For instance, Tasiilaq in Greenland:
Annual temperature in Akureyri, northern Iceland
The AMO turns cold
Around 1960 the AMO turned abruptly to enter its cold phase. And as the above graphs show, the effect was just as dramatic.
And as Lamb reports, there was a resultant massive expansion in Arctic sea ice.
HH Lamb: Climate, History and the Modern World – p271
Indeed, as a recent paper by Gagne et al, Aerosol-driven increase in Arctic sea ice over the middle of the 20th Century, found, recently recovered Russian observations show an increase in Arctic sea ice from 1950 to 1975 as large as the subsequent decrease in sea ice observed from 1975 to 2005.
According to NOAA, the AMO is an ongoing series of long-duration changes in the sea surface temperature of the North Atlantic Ocean, with cool and warm phases that may last for 20-40 years at a time and a difference of about 1°F between extremes. These changes are natural and have been occurring for at least the last 1,000 years.
But for the current batch of activist polar scientists, it might as well never have existed.