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Topics - Comradez

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Arctic sea ice / Will the Bering Sea ever be the same again?
« on: June 30, 2019, 08:20:15 PM »
One of the most dramatic developments this year has been the record warmth in the Bering Sea and Chukchi Sea.  For anyone who has not been paying attention, here are two articles that summarize what has been going on:

As Arctic neared 2019 winter max, Bering Sea was virtually ice-free
18 March 2019
https://news.mongabay.com/2019/03/as-arctic-neared-2019-winter-max-bering-sea-was-virtually-ice-free/

Record-Breaking Heat in Alaska Wreaks Havoc on Communities and Ecosystems
MAY 30, 2019
https://www.smithsonianmag.com/science-nature/record-breaking-heat-alaska-wreaks-havoc-communities-and-ecosystems-180972317/

The ocean along the Alaskan coast is already getting up to around 15 Celsius in some places.  That's 60 F.  Almost warm enough for a cool dip in the water!  And this has been having a huge effect inland as well.  These past several weeks they have been having highs around 70 F and lows around 50 F along the Yukon and Kuskokwim rivers.  That's about 10 F above normal. 

This winter, the sea ice is going to have a hard time overcoming all the warmth absorbed in the Chukchi Sea...and then overcoming all of the warmth in the Bering Sea...so much so that I really don't see how the Bering Sea ice can bounce back from this.  We may be witnessing the transition of the majority of the Bering Sea from seasonally ice-free to perennially ice-free. 

Last year the sea ice extent only made it down the coast of Alaska to roughly the area just barely past the Yukon River delta (see map below).  Norton Sound only had the most tenuous tendrils of ice for a couple of days at most.  For most of the winter, the ice extent didn't even make it past Nome. 

Map of Norton Sound region:



Map of Bristol Bay farther south:



How far south along the Alaskan coast will the ice make it in 2020?  Going from north to south, here are the options (could we make this into a poll?):

  • Not even making it to the Bering Strait (significant open water in Chukchi Sea all winter, no continuous ice in Bering Sea)
  • Bering Strait (no continuous ice in Bering Sea, but no significant open water in Chukchi Sea)
  • Nome
  • Yukon River delta (as far south as Nunivak Island)
  • Kuskokwim River delta
  • Bristol Bay (Dillingham/Port Heiden)
  • Port Moller
  • Cold Bay or farther

In the last decade, this is roughly how far the continuous sea ice extent has made it each winter (by continuous, I mean that I am not counting little microscopic pieces of ice in sheltered bays as part of the ice extent unless it is continuous with the rest of the Bering Sea ice pack) :

2010:  Port Moller (March 23rd)
2011:  Bristol Bay (Dillingham/Port Heiden) (March 4th)
2012:  Cold Bay (March 21st)
2013:  Bristol Bay (Dillingham/Port Heiden) (March 24th)
2014:  Bristol Bay (Dillingham/Port Heiden) (March 19th)
2015:  Bristol Bay (Dillingham/Port Heiden) (March 15th)
2016:  Kuskowkwim River delta (March 9th)
2017:  Port Moller (March 28th)
2018:  Kuskowkwim River delta (March 12th)
2019:  Yukon River delta (March 22nd) Edit: Kuskowkwim River delta (Jan 20th)

I'm gonna put my bet on Nome edit: the Yukon River delta areaThat is to say, I think there are better than even odds that Norton Sound won't even ice-over this coming winter.  hat-tip to Niall Dollard for pointing out that the ice extent was much farther in January and February of 2019, with Norton Sound solidly frozen and the ice making it all the way beyond the Kuskokwim delta area.  I honestly didn't even think to check dates that early in worldview.  I've changed my prediction accordingly.

2
Consequences / Arctic Thermal Oases and agriculture?
« on: July 02, 2017, 05:03:19 AM »
Recently I've been fascinated by the discovery that there are apparently so-called "thermal oases" in the high Canadian arctic.  There seem to be at least 3 of them:  Ellesmere Island around Lake Hazen, the area of Ellesmere Island around and Tanquary Fiord, and the east section of Axel Heiberg Island. 

Due to a combination of foehn winds, topographic shelter from the arctic ocean and nearby glaciers, and of course high summer insolation, these areas apparently routinely have up to 75 frost free days each summer.  You can verify for yourself on worldview that these areas often lose their snowcover by mid-June and remain without snow until the beginning of September.  In 2012 these areas even lost their snowcover by the first week of June.  Apparently, common summer temperatures are anywhere from 5 Celsius to as high as 20 Celsius. 

Of course, these areas still get bone-chilling cold in the winter.  But I can't help but wonder whether we might see the effects of climate change pop up in these areas sooner than some other areas further south. 

In fact, there are fossilized trees in these parts from the Eocene, especially on Axel Heiberg Island.  Surely we will not see the return of forests to these parts anytime soon.  But might we see more modest changes sooner than expected in these parts? 

On a related note:  I wonder if summer agriculture might ever become possible up there within our lifetimes.  I wonder if it might even be possible now, with the right setup.  Now, I'm sure it will not be economically efficient to do...but I wonder...could it be done?  The space colonist in me is curious.  What I mean is, even though these parts of the Earth aren't a different planet, they might as well be from the way they look in most pictures I've seen.  When you look at pictures of these places in the summer, they have a very "Martian" feel to them:  gentle plateaus all brown and desolate-looking despite the warm-looking sunlight falling upon them. 

And for some reason the idea of colonizing these parts and growing all the food and fuel you'd need for survival and heating appeals to me.  And yes, I know that the natives hunt seals, musk ox, etc. and survive just fine without any fancy agriculture...but still, I wonder.  What if you didn't want to reduce any of those herds?  What if you were vegetarian and wanted to live really self-sufficiently?  Could it be done? 

At first glance, it would appear that the length of the frost-free growing season and the summer temperatures are not the main issue.  There are many crops that need only 45-75 frost free days to grow and which grow just fine at any temperature above 5 Celsius:  wheat, lettuce, radishes, peas, broccoli, spinach, carrots, celery, etc. 

My guesses for what would most hold back agriculture up in these parts would be:
1.  High winds.  You would need either just the right topography, or a man-made windbreak, or an indoor greenhouse to protect crops from the constant high winds that will wear down anything but the shortest grass or arctic willow. 
2.  Permafrost.  You would need to either have raised beds set in special containers, raised off the ground on pylons to keep the soil from the icy touch of the earth, or you'd need a greenhouse. 
3.  Bad soil quality.  Even if you did get enough soil thawed out in the June sun, the "soil" up there is crap.  But...speaking of crap, might it be possible to gradually "Mark Watney" your way to a stockpile of better soil, if you know what I mean
4.  Lack of precipitation.  You would have to hand-irrigate all of your crops.  So, you would need to settle near some fresh water source that thaws by mid-June.  But I imagine it would not be enough to just collect the barely-thawed water as-is.  It would still be ice-cold, and I imagine quite a shock to the root system of any crop.  Perhaps the key would be to set any collected water aside for a week in some black-painted troughs to warm up to ambient temperature. 

So, basically, you'd need a greenhouse.  And it would have to be relatively big.  First, you'd only get one harvest for the whole year (although I wonder how much more vigorously some crops would grow in the 24-hour sunlight...)  Second, if you really wanted to live self-sufficiently and not rely on imported gas for heating, you'd need to have enough chaff at the end of the harvest to burn in your little bedroom to stay warm during the entire winter.  That would be the real challenge. 

3
Forecasts of high and low pressure largely tell us whether we can expect clear skies or cloudy skies in a given area.  Lately some people on the forums have been focusing a lot on these forecasts and making grandiose claims about the implications of such forecasts.

In order to determine whether such forecasts are bound to be "bad" or "good" for ice melt, I think it would be instructive to imagine what a "best case scenario" and a "worst case scenario for heavy ice melt would look like in terms of the seasonal timing of cloud cover. 

Let's begin by identifying the positive and negative feedbacks in the cloud/ice system.  Let us begin with a number of assumptions:

Main premise:  clouds block a large amount of both incoming AND outgoing radiation.

Assumption #1.  In the winter, when there is no incoming sun anyways, clouds are mostly blocking outgoing radiation, keeping heat in the atmosphere and acting as a POSITIVE feedback on ice melt (helping to keep the winter ice thin and priming the next melt season).

Assumption #2.  In the melt season, when there are incoming sun rays, but where there is still white snow reflecting 90% of incoming radiation back into space, clouds are STILL blocking outgoing radiation more than they are blocking incoming radiation that would actually stick around otherwise, so on the balance I would say that even during the melt season, clouds STILL act as a positive feedback on ice melt when the clouds are over high-albedo (very white) areas. 

Assumption #3.  ONLY during the melt season where the albedo has already dropped/darkened do clouds act as a negative feedback on ice melt.

Assumption #4.  If sunlight falls on areas of the globe that are far from the melt front of the icepack/snowpack, let us assume that some of the resulting surface heating / ocean heating gets transferred through air and ocean currents to the melt front to contribute to the melt season, but that the farther the sunlight falls from that melt front, the more of that surface heating / ocean heating escapes to space before it has any effect on the arctic snow and ice. 

IF we accept the assumptions above, then what would a "best case scenario" and a worst-case scenario for ice melt look like?

Best case scenario for ice melt: 
1.  Cloudy arctic in the winter.
2.  Sunny skies and warm air currents along the snowpack melt front zone in the mid-lattitudes from February to May (even if this has to be counter-balanced by slightly cooler temperatures in areas where the snow/ice would be safe in any case at this time in the season).
3.  Aggressive retreat of snowcover from February through May.
4.  The sunny skies and warm air currents follow the snow/ice melt front.  Cold snaps in April where Texas is in the 40s and DMI 80d-North is below zero are okay if these things are balanced out by heat waves along the melt front zone, such as along the Great Lakes or Southern Hudson Bay.
5.  Warm air currents push ice away from the coast in the Kara, Laptev, Beaufort, and Chukchi seas during May.  Clear skies and sunlight then immediately follow up in these areas, accelerating the melt, while DMI 80d-North remains cloudy. 
6.  Finally, dispersion and melt ponding reach the Central Arctic Basin by June, thereby lowering the albedo there enough that it pays to get rid of the clouds.  The clouds disperse and the melt accelerates there. 

Worst case scenario for ice melt:
1.  Clear skies in the arctic during the winter. 
2.  High-anomaly temperatures in the spring are concentrated in areas that are either safely far south to not have to worry about snow cover, or safely far north that the snow/ice will not be melting even with high anomalies.  Along the melt front, the weather is cloudy and snowy, and temperatures remain below normal.  Snowcover and albedo remain above normal. 
3.  Sluggish retreat of snowcover from February through May.
4.  Cloudy skies and cool air currents follow the melt front during the spring.  Areas away from the melt front to the south might receive sun and high temperature anomalies, but it doesn't matter.  Areas away from the melt front to the north might receive sun, but the albedo is going to be high enough that this will not translate into higher temperatures, but rather, in fact, lower temperatures as more heat escapes to space.
5.  There are not any warm air currents to push ice away from the coasts in the Kara, Laptev, Beaufort, and Chukchi seas during May.  The warm air currents are concentrated elsewhere--probably further south where it no longer matters, or north of 80-North, which doesn't matter as much because even with the high temperature anomalies, the 80-North is still below freezing at this time, and its albedo does not drop. 
6.  Finally, from June to August, the Central Arctic Basic experiences cloudy skies. 

Basically, the way I see it, for optimal ice melt, each stage of the melt front has to bootstrap the next.  High temperature and high sunlight/low cloudcover anomalies have to closely track the melt front.  Elsewhere, these anomalies are relatively wasted and can at times even be counter-productive unless they are closely tracking the changing melt front region as the season progresses to take advantage of newly-opened up dark areas that can soak up sunlight near the melt front to transport that heat there. 

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