Contribution of local human activities to sea ice melt

[Paddy]

Has anyone calculated what scale of positive feedback may be expected from increasing human activities within the arctic circle as a result of the ice melt leading to further ice melt?  I can see five main ways in which human activity seems set to increase:

1) Increased freight shipping, especially via the Northern sea route
(Numbers are up from 4 ships in 2010 to 46 vessels in 2012, shipping 1.26 million tonnes, to a predicted 20 million tonnes shipped in 2020)
2) Increasingly northerly fishing
3) Exploratory drilling
4) Infrastructural upgrades, mainly to support 1-3, e.g. harbour expansion and floating nuclear power plants
5) Science and tourist traffic

I'm particularly wondering if the extent to which this has all increased already might be part of why the melt went on longer in 2012 than prior years, and hence if we might expect a repeat of the long melt this year as shipping etc. looks set to rise further.  What I haven't found is any numbers on the likely impacts of such changes, to tell me whether I'm barking up the wrong tree or not.  Can anyone help me out on this?

[Neven]

The effect of ships breaking up ice is minimal, but their exhaust (read: soot particles) could have a more than minimal effect. Very hard to quantify though.

[Paddy]

So the general consensus is [minimal mechanical break-up] + [minimal local heating] + [possibly more-than-minimal effect on solar heat absorption via soot]=[possibly more-than-minimal total effect]?

[anonymous]

Can anyone help me out on this?

Paddy, include the size of the Arctic in your calculation. Imagine 20 icebreakers in an ocean twice the area of Australia. You'll need a lot of zeros after the comma for a serious impact calculation. However, this instantly changes if you include wells leaking black crude enduring all seasons in cold Arctic waters. So keep an eye on the Prirazlomnoye platform.

[Paddy]

Can anyone help me out on this?

Paddy, include the size of the Arctic in your calculation. Imagine 20 icebreakers in an ocean twice the area of Australia. You'll need a lot of zeros after the comma for a serious impact calculation. However, this instantly changes if you include wells leaking black crude enduring all seasons in cold Arctic waters. So keep an eye on the Prirazlomnoye platform.

However, there is a small force multiplier in the way that icebreakers and other vessels don't act throughout the arctic, but more near coastlines and through straits etc., and don't act throughout the year, but mostly when the ice is near its minimum.  Also, they include some pretty big and powerful vessels (including the nuclear-powered Arktikas), and there are a few more than 20, though I don't know how many are active in the Arctic at one time even during peak traffic.  And then, of course, there are the further mechanical and locally-warming effects of the other ships that follow them, or that skirt around the edges of the ice, but I take your point.

[Neven]

Paddy, here's a good piece that was on the NSIDC Icelights blog: Are icebreakers changing the climate?

Conclusion:

How much ice does an icebreaker break?
Meier decided to crunch some numbers and find out. While his numbers are an estimate, he said, they provide a helpful comparison of just how much icebreakers might contribute to summer ice loss.

Meier said, “In late June, when the sun’s energy is strongest, the total sea ice extent is around 10 million square kilometers or 3.9 million square miles. An icebreaker cruising through the ice for 1,000 kilometers (620 miles) and leaving an ice-free wake of 10 meters (33 feet) would open an area of water 10 square kilometers (3.9 square miles) over the entire cruise.

In contrast, the Arctic sea ice cover decreases by an average of over 9 million square kilometers or 3.5 million square miles each year during its melt season—an area larger than the contiguous United States.  In total, researchers estimate that the number of icebreakers traversing the Arctic at any given time is usually less than three. So, Meier said, “The actual contribution is miniscule—only one part in a million of the total ice cover.”

[Paddy]

Heh, OK, I suppose that does answer it pretty well.  (Although the bigger icebreakers are 30 metres in beam, not 10 metres, and to have a fuller estimate, I'd still like to know how many thousands of km are travelled by icebreakers moving through the ice in total each year ... incidentally, ). 

[Alistair]

The video was interesting but ...

As per the commentary, the notion of an ice free North Pole is just ridiculous ;-).

It wasn't leaving an ice free wake, it was leave a sea of broken, slightly cracked ice behind it so I don't think the impact of a bunch of icebreaker across the expanse of the Arctic is going to be very much.

This trip is also an exception (it's not like it is a daily occurrence that one of these things goes to the pole).  The main use is to guide traffic along the northern sea route and the like where they will be travelling along defined lanes not going around breaking as much virgin ice as they can every trip.

[Laurent]

The icebreaker have no impact on the ice ?
It was certainly true in the recent past but now that the ice is thin (around 1m), that does certainly play a role ! The reason is, the icebreaker create some edges (late spring, summer, early automn) where the sea can attak the ice, it does mix the algae and the ice, increasing the algal activity, dimishing albedo, it does bring some soot strait where it should not be...
Because they follow the same path, it is not a problem ?
Of course no, the ice drift so taking the same path they will regularly streake the ice and create some spagueti.
Very soon there won't be any ice left in summer, we will have to see for the rest of the year so ... !
Busyness as usual is not an option !!!

[jdallen]

The icebreaker have no impact on the ice ?
It was certainly true in the recent past but now that the ice is thin (around 1m), that does certainly play a role ! The reason is, the icebreaker create some edges (late spring, summer, early automn) where the sea can attak the ice, it does mix the algae and the ice, increasing the algal activity, dimishing albedo, it does bring some soot strait where it should not be...
Because they follow the same path, it is not a problem ?
Of course no, the ice drift so taking the same path they will regularly streake the ice and create some spagueti.
Very soon there won't be any ice left in summer, we will have to see for the rest of the year so ... !
Busyness as usual is not an option !!!

In terms of scale, the pure mechanical impact *will*  be trivial.  The YAMAL on its trip back and forth across the center of the arctic at *most* would have disrupted a total surface area of about 200 KM2.  At that, it would not have created leads, just created a broken up section of ice.  All in all, compared to natural forces, we are still talking about less than 1/20th of one percent of daily changes to the ice.

Soot is another issue entirely, as it isn't applying energy directly; rather it permits energy to be applied, a big difference.  It provides an odd argument in favor of nuke-powered icebreakers, for sure.

[Laurent]

The yamal was alone, we are talking of around 50 boats every day (or more) (not necessarily icebreaker)!
The mechanical strength of the ice is important in the melting at the microscopic level but also at the Arctic level, we are seeing right now the effect of a mechanical separation due to the opening in the middle of the central arctic...exiting and terrifying.
Nuclear power is not a option either (unless you can guaranty the safety of the people after 100 years, unless you can pay the assurance in case of problems type Fukushima...)
The polar passage will be a major one simply because it is shorter from China to Europe !

[jdallen]

The yamal was alone, we are talking of around 50 boats every day (or more) (not necessarily icebreaker)!
The mechanical strength of the ice is important in the melting at the microscopic level but also at the Arctic level, we are seeing right now the effect of a mechanical separation due to the opening in the middle of the central arctic...exiting and terrifying.
Nuclear power is not a option either (unless you can guaranty the safety of the people after 100 years, unless you can pay the assurance in case of problems type Fukushima...)
The polar passage will be a major one simply because it is shorter from China to Europe !

I'll leave a discussion of nukes for a different thread; it is a topic which generates more passion than I care for.   The polar passage won't be used until it is virtually ice free.  That said, even fifty ice breakers would have a negligible effect in the ice compared to natural forces.  It is a matter of scale and amplification.  Human activity has an appreciable effect only when it is amplified by nature, and/or when it is over longer timescales (e.g. conversion of land for agriculture.).

That is part of why we end up having to fight so hard in our efforts to change our collective behavior. The feedback is indirect.

[ChrisReynolds]

You just have to look at the movement of the pack as seen in timeseries of ASCAT/Quikscat to appreciate the small effect ice breakers have on the pack.

EDIT, link to ASCAT timeseries:
https://docs.google.com/file/d/0B3pB-kdzoLU3enpsVkZGZDdFZEk/edit?usp=sharing
Such movement of the pack is common to all years and it is only accomplished with a lot of cracking (tension) and ridging (compression), that image is of the widespread fracturing seen this winter, but the pack is always on the move as shown in the animated gif.

[Laurent]

I am seeing the goat's head in the animation ! (for whose who are looking for it)
My point is not the past or even now but in the near futur.
Ice free arctic is shedule around 2015, when we are on the edge the human activity will take all the opportunities available, especially if it is faster, cheaper.
Does any one know how many ships could we expect if the way was safe replacing Panama, Suez canal ?

[Juan C. García]

Heh, OK, I suppose that does answer it pretty well.  (Although the bigger icebreakers are 30 metres in beam, not 10 metres, and to have a fuller estimate, I'd still like to know how many thousands of km are travelled by icebreakers moving through the ice in total each year ...

Suppose that an icebreaker enters to this melt pond. Should we be concern that warmer water enters inside the pond, making the melt faster that before the ice breaks, or we will still considered just the beam of the icebreaker.

(Log in to view the image)

[Bob Wallace]

If Bill Gates finds a dime on the sidewalk should we re-figure his net worth?

[Juan C. García]

If Bill Gates finds a dime on the sidewalk should we re-figure his net worth?

Even that I can agree that the impact is not important in 2012 or 2013, I share the concern of the possible impact in 2020, when the traffic with Japan and China with Europe and Eastern USA will be with ships crossing the Arctic Ocean, possibily as early as May.

[Bob Wallace]

The impact will be mixed.  There will probably be a regular route that will get more stirring up but overall it will be a small percentage of the greater Arctic.  And there will be more soot on the ice.

But there will also be a fuel savings which will mean something in the way of less CO2 emissions.

[Juan C. García]

The impact will be mixed.  There will probably be a regular route that will get more stirring up but overall it will be a small percentage of the greater Arctic.  And there will be more soot on the ice.

But there will also be a fuel savings which will mean something in the way of less CO2 emissions.

Sounds reasonable both (positive and negative feedbacks). Maybe I am just being emotional, but I feel like the last place of Earth without human activity is going to lose its virginity.

[Anne]

The impact will be mixed.  There will probably be a regular route that will get more stirring up but overall it will be a small percentage of the greater Arctic.  And there will be more soot on the ice.

But there will also be a fuel savings which will mean something in the way of less CO2 emissions.

Sounds reasonable both (positive and negative feedbacks). Maybe I am just being emotional, but I feel like the last place of Earth without human activity is going to lose its virginity.

It lost that a long time ago. The sea ice has the trick of being a virgin again each year, but the merkin is beginning to wear thin.

[Paddy]

Oh dear, what have I started...  Anyway, as I see it there are lots of feedbacks in this vein, but the effects of just about all of them are individually minimal:

Positive:
- Soot production
- Direct mechanical destruction of ice sheets by icebreakers
- Indirect mechanical disruption of ice and facilitation of warming by the wake of ship traffic
- Disruption of refreezing by the wake of ship traffic
- Local heat production of ship traffic and new arctic stations, e.g. drilling platforms, floating nuclear power plants, expanded harbours etc.

Negative:
- Less carbon-intensive shipping (no great effect, as there may well be more shipping overall, and the icebreaker escort requirement cuts into the saving).

Such minimal impact as this would have would mostly be when the ice has retreated enough to allow ship traffic, so in the months of June to November or so.  If I were to speculate, I'd reckon it might have more of an impact on stopping the annual refreeze than on facilitating the melt (thinking about the effects of the turbulence caused by the ships passage), hence contributing very slightly to how late in the year the refreeze begins.  Even the 1.5 million or more tons of cargo that might be shipped this year and the ships required to carry that are pretty small potatoes compared to the size of the ocean they're in.  But they may well keep the northern sea route itself open a little longer, albeit without generally impacting the rest of the ocean.

[lanevn]

Strange, that this article still is not here http://www.washingtonpost.com/blogs/wonkblog/wp/2012/12/04/want-to-slow-arctic-melting-stop-flying-over-the-north-pole/