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Poll: In order of Severity with regard to Arctic Sea Ice Which do you feel will occur?

Arctic Ice Free by 2060 (Sept. Minimum)
5 (9.3%)
Arctic Ice Free by 2040 (Sept. Minimum)
21 (38.9%)
Arctic Ice Free by 2020 (Sept. Minimum)
23 (42.6%)
June 21st Arctic Ice Free (within 10 years of 560 ppmv CO2 in atmosphere)
2 (3.7%)
June 21st Arctic Ice Free by 2050
3 (5.6%)

Total Members Voted: 53

Voting closed: June 15, 2015, 10:03:20 PM

Author Topic: When Will We See <1,000 km^2 Arctic Sea Ice Extent  (Read 23045 times)

jai mitchell

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Re: When Will We See <1,000 km^2 Arctic Sea Ice Extent
« Reply #50 on: June 07, 2015, 05:18:34 AM »
“ECS is actually 6C when arctic sea ice feedbacks are taken into account”

you are sorely mistaken if you think that we wont experience <1,000,000 km^2 of arctic sea ice by June 21 under 2XCO2 forcing. This means an additional globally averaged albedo feedback of about 0.23 watts per meter squared for each 1,000,000 km^2 loss. (may be as high as 0.3 but I low-estimate) The 1970-1980 mean of ice for June 21 is about 11,000 KM^2 so this ice free state is equivalent to about 2.3 watts per meter squared globally averaged forcing feedbacks compared to pre-industrial.

Add that to the 3.7 of 2XCO2 and you get 6.0 Watts per meter squared without other feedbacks This calculation neglects the reduction of oceanic Dimethyl Sulfide production which is projected to yield (median) +0.3 C of warming feedback, as well as other feedbacks such as carbon cycle, frozen soils and far-infrared emissivity reductions and increased arctic algae blooms causing further albedo effects.

not to mention northern hemisphere snow-cover anomalies.

since our best estimate so far is 0.6C of globally averaged warming for each 1.0 Watt per meter squared that is 3.6C of warming just for CO2, WV/Lapse Rate and Arctic sea ice. Add the 0.3 DMS feedback, emissivity and algae bloom effects and you end up with ~4.3C as a baseline response.

Then you can add cloud feedbacks, snow cover albedo effects, frozen soil effects and carbon-cycle effects.

as you can see the 6.0C ECS is a low-end estimate. This is why we will have to engage in geoengineering activities, including dimming and CO2 atmospheric extraction.
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oren

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Re: When Will We See <1,000 km^2 Arctic Sea Ice Extent
« Reply #51 on: June 07, 2015, 10:22:41 AM »
...

This means an additional globally averaged albedo feedback of about 0.23 watts per meter squared for each 1,000,000 km^2 loss. (may be as high as 0.3 but I low-estimate) The 1970-1980 mean of ice for June 21 is about 11,000 KM^2 so this ice free state is equivalent to about 2.3 watts per meter squared globally averaged forcing feedbacks compared to pre-industrial.

...


Is this calculated on an annual basis? meaning 1 month (or season) of 1M KM^2 at top insolation is equal to 0.23 watt globablly averaged annual forcing? Just making sure I understand correctly.

jai mitchell

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Re: When Will We See <1,000 km^2 Arctic Sea Ice Extent
« Reply #52 on: June 07, 2015, 01:45:58 PM »
This is a globally averaged, annual forcing parameter associated with the loss of a single 10^6 km^2 of sea ice missing on June 21.  Within this value is an assumption that a significant amount of sea ice had already been missing as early as late April.

This is why a 10X10^6 km^2 reduction in sea ice in the year 2065 produces 2.3 Watts per meter squared (globally averaged) forcing in that year.
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oren

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Re: When Will We See <1,000 km^2 Arctic Sea Ice Extent
« Reply #53 on: June 07, 2015, 03:40:08 PM »
Thanks for clarifying

jai mitchell

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Re: When Will We See <1,000 km^2 Arctic Sea Ice Extent
« Reply #54 on: October 14, 2016, 08:31:25 PM »
Great piece on the implication of a low aerosol 400 ppm arctic future:  https://www.skepticalscience.com/print.php?n=2845

I believe that the combination of economic cycle + program reductions in chinese sulfate emissions plus increased atmospheric water vapor from the 2015 ENSO cycle is driving the collapse of the polar cell and a shift into a new state of +8C arctic warmth.  This transition will likely be complete within the next 7-14 years with advanced and early arctic sea ice < 1,000,000 km^2 SIE values approaching June 21 around 10 years after that. 

The increased albedo of this effect alone will produce an additional increased globally averged forcing of 2.3 W/m^2.

We are starting to see the beginning of this shift this now.

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are not tri-color bar graphs
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