“Pytheas visited an island six days sailing north of Britain, called Thule. Probably Thule was (part of) the Norwegian coast, although Iceland, the Shetland Islands and Faeroe Islands have also been suggested by historians. Pytheas says Thule was an agricultural country that produced honey. Its inhabitants ate fruits and drank milk, and made a drink out of grain and honey. Unlike the people from southern Europe, they had barnss, and threshed their grain there rather than outside.

He said he was shown the place where the sun went to sleep, and he noted that the night in Thule was only two to three hours. One day further north the congealed sea began, he claimed. As Strabo says (as quoted in Chevallier 1984):

Pytheas also speaks of the waters around Thule and of those places where land properly speaking no longer exists, nor sea nor air, but a mixture of these things, like a “marine lung”, in which it is said that earth and water and all things are in suspension as if this something was a link between all these elements, on which one can neither walk nor sail.

The term used for “marine lung” actually means jellyfish, and modern scientists believe that Pytheas here tried to describe the formation of pancake ice at the edge of the drift ice, where sea, slush, and ice mix, surrounded by fog.
After completing his survey of Britain, Pytheas travelled to the Shallows on the continental North Sea coast. He may also have visited the Baltic Sea, but he did visit an island which was a source of amber, probably Helgoland.

No record survives of his return voyage. He may have returned by the way he came; or perhaps by land, following the Rhine and Rhône rivers. ”

http://www.fact-index.com/p/py/pytheas.html

Only because his vocabulary was not up to describing sea ice, which he had never seen before.

There’s an old story about an African sent to observe a missionary preaching to his flock.
The African reported to his people that a man wearing a dress held a black bird with speckled wings in his hands and when the wings were spread God talked through the man in the dress.
The African had no words in his vocabulary for Book, pages, printed words, reading , etc.

There have been recalculations that took into account previous errors in calculations and the island was pinpointed.
The odd description has been recognized to mean that the ship could not make land fall due to drifting pancake ice and debris and thick mist or fog.
Similar descriptions of fog making it hard to tell where the sea ended and sky began are found in much later tales of the sea, but are more easily understood.

I’m no scholar, I just had a strong interest in history, and the less that was known for certain the more my curiosity was peaked.
Legends often have a basis in fact, and this is an example.
The Icelandic Sagas are more than a cut above legends and are in the realm of historical facts and observations.

Great disasters leave their mark in legend, written accounts, and in modern archaeology.
Sifting through this to find truth is not always easy, but taking the easy way out by simply ignoring it all because it would be inconvenient to your world view is not very honest.

When events were written down long after the fact there were procedures in use since Ancient Greece to get at the truth.

It would not be surprising to see a lot of sea ice in 1695, as that was a relatively cool period in the Northern Hemisphere:

http://www.skepticalscience.com/new-remperature-reconstruction-vindicates.html

I’ll dig up links to a few.
The maps of the Norwegian sea include the eastern tip of Iceland, not the entire island. Maps like this don’t stop at the demarcation they show the limits of the sea and surrounding waters. Land for some distance beyond the NS is shown as far as Greenland.

“Also remember that deep in winter there may be some drift ice floating through the Denmark Strait which means ice may be pushed towards Iceland. There is also ice coming from some of the glaciers. And yet, none of this means there was any problem with sea ice for those poor Vikings in their small boats, since they travelled primarily in spring and summer.”

They didn’t travel to Iceland at all before the 9th century.

The Greek who first saw “Ultima Thule”, believed to be one of the Norwegian islands further south, described it in terms that modern mariners recognize as being surrounded by plate ice impassable for sailing ships of that day.

So was the Norwegian sea always free of significant sea ice before the 7th century?
Irish Monks had reached Iceland in the 6th century, and it was warm enough for them to set up a settlement. How much ice did they have to contend with?

In 1695 Iceland was completely locked in ice, the inhabitants were in peril.
That on the edge of the warmer Norwegian Sea.

The main point is the ice around Greenland. That we know became impassable at the end of the Medieval Warming Period.

The Norwegian sea as I said didn’t have much sea ice, and neither did the Greenland sea during the MWP.

The Cog was the safer choice when drifting sea ice returned .
Besides its sturdy cross beam braced hull that could better withstand impact with drifting ice, the crew and cargo were better protected from the elements , and the Cog had a primitive but effective bilge pump to handle sea water that reached the hold during storms at sea.

During the MWP passage to Iceland and Greenland, not to mention navigating around the entire island of Iceland as the first Viking explorers had done, was a cake walk compared to later centuries, until more recent times at least.

Here’s a rough map without ice
http://www.worldatlas.com/aatlas/infopage/norwegiansea.htm
Note only the very eastern tip of Iceland touches the Norwegian sea.

As listed here
http://en.wikipedia.org/wiki/Norwegian_Sea
The “Basin Countries” are Iceland and Norway.

I’ll add a few sea ice maps later.

If you mean the Norwegian Sea, I’d love to see those maps, because the Norwegian Sea formally does not include Iceland and the Norwegian Sea is considered ice-free all year round.

Also remember that deep in winter there may be some drift ice floating through the Denmark Strait which means ice may be pushed towards Iceland. There is also ice coming from some of the glaciers. And yet, none of this means there was any problem with sea ice for those poor Vikings in their small boats, since they travelled primarily in spring and summer.

China
https://www.google.com/url?q=http://faculty.fgcu.edu/twimberley/EnviroPol/EnviroPhilo/WarmPeriod.pdf&sa=U&ei=1JHIVNyoH8W7ggTviYPoBg&ved=0CAcQFjAB&client=internal-uds-cse&usg=AFQjCNEQfMGbGQ5dxj8I1KY2N81r2OEC9Q

BTW
The Cog was braced with cross beams in much the same way as Roman era ingot/ore carriers of the Gauls.
The Romans wrote that these ships were not vulnerable to damage by ramming because of the cross beams one foot thick.
The Romans adopted this design for merchant ships sailing in the Atlantic. The “Asterix Ship” now under study is the best known example.
Most modern maps of the Norway Sea that I’ve seen show Iceland pretty much surrounded by sea ice except for the eastern tip.
Greenland seems to have been little troubled by sea ice till aprox 1300 about the time that sea ice became a concern in Iceland. As sea ice increased the Greenland settlements became unsustainable. The cargo ships, even the sturdiest, just stopped coming, it wasn’t worth the risk.
Dunwich was inudated by an epic storm and partly destroyed in 1286, another massive storm pretty much completed the job in 1347.

The cities and town in Britain and on the coast of the continent destroyed by storms during and towards at the end of the Roman era are harder to pin down, some sliding into myth.
Earlier the Romans had written of the seas around Albion being unusually calm and easy sailing.

The subject is whether the effects of Global Warming are being felt earlier than predicted.
If more than one factor is at work then why not investigate any possible contributors.
Generally unexpected events are due to a combination of factors.
Look in one direction too long and we might get blind sided.

The greatest storms, the ones that destroyed cities and inundated the countrysides destroying other towns and villages driving inhabitants inland seem to have come towards the end of those warming periods.

When all you have is a hammer every problem looks like a nail.