North Pole melts -900 AD

[Umbral]

There is a big discussion in scientific cirles about warm cycles versus man-made climate change. What seems to be beyond dispute is that the north polar sea has been ice free for long periods, in fairly recent times. On a geologic scale.

What is the climate passes a tipping point, the arctic warms up a bit, and the north polar ice cap melts -over the period 850-900 AD?

As the ice vanishes, there would likly be some futher warming, as the darker sea absorbs more sunlight.

Now the map does not cut off at the top anymore. You need to look at the globe insted. The north of Norway is equidistrant from Italy and Alaska. But Alaska is easier to sail to. The sailing distance that would take a longship to Cape Verde, will now take it nearly to Japan.

As well as all the vast territories in Siberia and Canada, going from nearly inacessible to close by in a stoke. And getting a slightly pleasanter climate.

I really cannot think of any remotely plausibe single event that would effectively change the map more than this. Short of an Ice Age.

Now what?

Edit: The distances are by air. In miles sailed, the miles that takes you to Rome from Northern Norway, would very nearly take you to Hokkaido in Japan.

 

[dreadnought jenkins]

well, I guess that could lead to a lot more viking settlement of the north? This was about the time before the vikings spread out or were starting to move out of their homelands... I don't know im no expert. But what about all that excess water and rising sealevels. What would that do.

 

[DuQuense]

Given a Ice free Artic, there are predictions of between 15~20 oC water tempurture in Summer. this means no return of the ice any time soon.
As this is mosly floating ice, it doesn't change the ocean level by much, immediatally, thro over time greenland [=+15m] will melt and cause a slow change.

whe will have a settlement of stizbergen,frans joesphland and the other russian artic islands, headed East, while the iceland/Greenlanders start west. The Inuit in the Americas, and the Reindeer Peoples of lappland/Siberia pick up on the Rus Culture as theirs has just collasped.
By 12~1300 the Rus Circle the Globe and dominate the Artic Sea.

 

[MarkA]

Sea levels would rise. Inundation of some lowlying areas and an increase in marshland and therefore maleria becomes even more endemic in the Med particularly Italy.

Of more concern would be the collapse of the Gulf Stream. All that extra fresh water in the ocean would mean the Gulf Stream simply stops. This would have an extraordianary effect on the British Isles.

Once Northern Europe warms to such a degree then the Tundra melts. All the extra CO2 released causes even more warming. Not to mention the effect on the ecology of the whole of the North. Mass migrations and extinctions leading to who knows what.

 

[NapoleonXIV]

Doesn't all the ice freshwater change the seawater salinity? And doesn't this cutoff the North Atlantic conveyor and cause the dreaded Lesser Dyas Ice Age scenario?

Now the Litte Ice Age comes 300 years early, and is a BIG ice age.

Or not, what could continue to keep the ice melted then?

 

[Umbral]

I've been thinking since last night.

Back then, there was the medival warm period, when the climate was warmer than today. It culminated around 1250 or so, to be followed by the little ice age, when the Thames froze over every winter.

Now I don't know what caused these changes, and given the complexity of climate mechanisms, I am not sure if anyone does know for sure.

But we could postulate that some mechanism that drove the warming in the middle ages got a little bit stronger. Some small butterfly effect cascading into a bit more warmth.
Once the ice caps melt, the ocean will absorm more heat, and the tundra will release CO2, reinforcing the effect.

The climatic consequences would be complex, but some of the more easily predicted ones are:

-No rise in sea levels. The north polar icecap is freefloating. If the temperature does increase to 15-20 degrees, we could see thermal expansion and runoff from Greenland fuel a minor rise.

-Gulf stream stops. This does not neccessarily lead to big changes, because of the general heating of the ocean that is occurring. We could instead see large areas of the arctic enjoy a climate like that enjoyed by the gulf streamed areas today.

-Tree lines creep northwards and upwards. Fish and animals migrate north, and the tundra turns into bogs, forest and grassland.

Greenlands coasts will probably warm, and the ice will retreat from the coasts. Nothern greenland may be marginally habitable, much like southern Greenland at the time, OTL. Southern Greenland may become more like the Oslo-Stockholm area OTL. Ice retreating from the sothern tip of the island entirely. There will not be anything like the scandinavian soil cover, of course.

Newfoundland warms as well, to something like Britain today. On the down side, the cod migrates north.

Siberia warms, Tundra turning into bogs. Digging for mammoth ivory may be a growth industry. Russias geography, with a lot of major rivers running northwards, is suddenly an advantage. The climate may end up as a more boggy and warmer version of Northern Norway.

The islands in the polar sea warms up to about the same level.

Ocean salinity changes, temporarily disrupting a lot of deep sea currents.



Of course the medeval warm period was followed by the little ice age. Now we are looking at two possibilities. Either the warming has proceeded so far as to be self-sustaining.

Or conditions will tip back, but this time with the gulf stream gone. If so, I could see a short, real ice age spell following the warm spell.

The little ice age reached its peak in the 1700s, I think. In TTL, it may lag a little, due to the climatinc inertia of the warm period.

But we would have had a brief golden millenium of the arctic acting as a second mediterranean sea, round, warm as bathwater, and with massive land areas and unexploited natural resources.

Untill the ice retuned, and scraped away every sign that there had ever been men there.

 

[Tocomocho]

-No rise in sea levels. The north polar icecap is freefloating. If the temperature does increase to 15-20 degrees, we could see thermal expansion and runoff from Greenland fuel a minor rise.

A melt of Greenland's ice would have some big consequences. For example, one million years ago the ice in Greenland was probably the half of today. What where the consequences? Well, look at the London of that time: it has a sea harbour, hippopotamuses and families of mosquitos that today only exist in Sub-saharian Africa, which are a probable indicative of the presence of now tropical diseases. The impact in human society would be inmense. For example, the horse is likely to became extinct in most of Europe due to the arrive of the tse-tse fly from Africa (apparently, the only cause because it doesn't attack the zebras is because there is something in their white/black pattern that repels the flies; the now extinct quaggas of South Africa had not this coloration because they lived in a region without the tse-tses). And the age of heavy cavalry in warfare is next coming...

 

[Umbral]

Melting the Greenland ice cap would have big consequences for sea levels, agreed.

I meant to say that the Greenland ice caps, being on land, would not melt anywhere near as quickly. The glaciers would retreat from the coastline, and this would cause some runoff. The melting of the inland glaciers would probably take centuries, if not millennia. Given that the warmer oceans around Greenland would lead to increased snowfall in winter, they might stabilize some miles from the coast.

If the Arcitic really did warm up to 10-20 degrees, there would be some thermal expansion to lift sea levels, but how much? Maybe a meter? (Random number pulled out of my hat. Anyone know?)

The horse point is really interesting...especially as the deep inlands, like Hungary and Mongolia might not have this problem...

 

[DuQuense]

Thermal rise is measure in mm/degree so whe are seeing 4-6 inches here [max]

the end of the little ice age in 1750, is blamed on the Great Clearing that started in 1250. and on the increasing CO2, from cutting down so many forests.

Here the Great clearing will start earlier, and be more widespread, so I don't see a return of the ice.
at least till the Astromonical forces tip so far, the Greenhouse effect is over Powered. [OTL shows a full thousand years at least here]

 

[MarkA]

All this sounds so benign. However...

An increase of 10-20 degrees would be catatrophic for the earth and for us! It would lead to the melting of the Antarctic ice cap, the complete change of current patterns in the ocean, mass extinction of the photoplankton and the collapse of the ocean food chain. Once that happens then life on earth is in real danger. It may come through like it has in previous mass extinctions, but there would be no humans around to witness it.

Temperature rises like that would mean no more winters and human habitation in southern Europe would be impossible in a few years with the zone of habitation shrinking dramatically year by year. Catastrophic droughts and/or severe flooding would destroy agriculture. With fish stocks gone or migrated to where the people cannot find them and domesticated land animals losing their environment, what are the humans supposed to eat?

Large temperature increases on this scale would mean forest fires would burn out of control for longer periods.

 

[Tyr]

This probally should be in ASB. Not just is it a big geographic change but its quite a impossible one (have the poles ever melted?....I don't think so. CMIW thought)

The standard answer is that we would enter into another ice age due to the dilution of the seas which would cause the caps to steadily reform with avengence.

But then again if we are removing the caps entirely we could well see a run away greenhouse effect due to sunlight not being reflected- also all that extra water in the atmosphere....Earth could well turn into Venus mark 2.

 

[Umbral]

All this sounds so benign. However...

An increase of 10-20 degrees would be catatrophic for the earth and for us! It would lead to the melting of the Antarctic ice cap, the complete change of current patterns in the ocean, mass extinction of the photoplankton and the collapse of the ocean food chain. Once that happens then life on earth is in real danger. It may come through like it has in previous mass extinctions, but there would be no humans around to witness it.

Temperature rises like that would mean no more winters and human habitation in southern Europe would be impossible in a few years with the zone of habitation shrinking dramatically year by year. Catastrophic droughts and/or severe flooding would destroy agriculture. With fish stocks gone or migrated to where the people cannot find them and domesticated land animals losing their environment, what are the humans supposed to eat?

Large temperature increases on this scale would mean forest fires would burn out of control for longer periods.

I think you misunderstand. We were talking about the warming of the arctic ocean. When the ice melts, the water there have risen to temperatures of 15 - 20 degrees, from about 0 today.

So only a rise in the sea temperatures of this area, not a global rise.

Of course, when it did rise that far, it was indeed a bad time:

http://news.bbc.co.uk/2/hi/science/nature/3631764.stm

But a rise of 5 degrees, local to this area, would have the same effects in terms of opening up the sea and land around it.

This probally should be in ASB. Not just is it a big geographic change but its quite a impossible one (have the poles ever melted?....I don't think so. CMIW thought)

The standard answer is that we would enter into another ice age due to the dilution of the seas which would cause the caps to steadily reform with avengence.

But then again if we are removing the caps entirely we could well see a run away greenhouse effect due to sunlight not being reflected- also all that extra water in the atmosphere....Earth could well turn into Venus mark 2.

Actually, it seems to not only be possible, but easy, and an occasional event. On a geologic scale. Don't forget that our present situation with ice caps is very unusual. The planet rarely has them.

But I am not sure if this would much affect Antarctica. Somewhat, I suppose, the initial warm spell, and slight reinforcing, but some of the Arctic feedback mechanisms would be local.

 

[MarkA]

I think you misunderstand. We were talking about the warming of the arctic ocean. When the ice melts, the water there have risen to temperatures of 15 - 20 degrees, from about 0 today.

So only a rise in the sea temperatures of this area, not a global rise.

Of course, when it did rise that far, it was indeed a bad time:

http://news.bbc.co.uk/2/hi/science/nature/3631764.stm

But a rise of 5 degrees, local to this area, would have the same effects in terms of opening up the sea and land around it.



Actually, it seems to not only be possible, but easy, and an occasional event. On a geologic scale. Don't forget that our present situation with ice caps is very unusual. The planet rarely has them.

But I am not sure if this would much affect Antarctica. Somewhat, I suppose, the initial warm spell, and slight reinforcing, but some of the Arctic feedback mechanisms would be local.

You cannot have a local event that raises temperatures that much. World weather does not work like that. The whole globe is interconnected by wind and ocean currents.

If the Arctic sea temperature rose by 15-20 degrees, then the rest of the planet would be so affected that life on earth would almost certainly enter a mass extinction phase.

 

[Umbral]

Quite true, from the link. And you clould have a rise in sea temperatures which had its biggest effect in the arctic.

However, as said, a few degrees work just as well for our purposes. And we can have that as a local event. With knock-on effects, of course, but without massively changing the planet.

Like the gulf stream being interrupted, but without melting the whole of Greenland and Antarcticas ice caps.

 

[arctic warrior]

Going for a say 5C warming of the arctic would still melt the sea ice and would make the glaciers of the northern hemisphere retreat in land, as they seems be. This would be enough to keep the Arctic Ocean - and we'd have to rename it - ice free. It won't have to warm to 15-20C as a swimmingpool isn't necessary, just a new cross polar highway. That would make for cod and other fish to move north and peoples would follow. Greenland would be much more welcoming for Eric and his followers - today they grow potatoes in southern Greenland.
Because of de-salination of sea water the Gulf stream would turn south and that would change weather in Europe and North Africa. If our wet weather in the British Isles and the Baltic move south to say the Med, Sahara might see another fertile season, something like the Med area today. But how would de-salination work on fish like cod? Would they go south yet again or die-off or adjust?
The perma frost in Siberia and Canada would thaw and release CO2, but I'm not sure if everybody agree on the final consequenses on these effects.
Peoples here at least seem to be divided in opinion.

 

[stevep]

The nasty bit that no one has mentioned is that if the northern cap melts and the permafrost in the Arctic goes then we will possibly get a lot of the methane tied up there being released. This would have a big impact on the climate as its a fair more [FONT=&quot]formidable [/FONT]greenhouse gas that CO2.

Steve

 

[arctic warrior]

The nasty bit that no one has mentioned is that if the northern cap melts and the permafrost in the Arctic goes then we will possibly get a lot of the methane tied up there being released. This would have a big impact on the climate as its a fair more [FONT=&quot]formidable [/FONT]greenhouse gas that CO2.

Steve

We'll I think that has been touched upon - but do scientists agree on what the long term effect will be???

 

[stevep]

We'll I think that has been touched upon - but do scientists agree on what the long term effect will be???

Think it would depend on how much methane was released how rapidly. However it would give a big , or possibly very big push to further warming.

Steve

 

[arctic warrior]

Think it would depend on how much methane was released how rapidly. However it would give a big , or possibly very big push to further warming.

Steve

But really it's a matter of belief - let's give it a few hundred years...

 

[MarkA]

But really it's a matter of belief - let's give it a few hundred years...

A matter of belief? Is science just a belief system on a par with religion?

Nonsense.