New historic sea ice minimum

[x-y-no]

Still about a month of melting to go and we've already got a new historic minimum:

Thursday, August 9, 2007 - New historic sea ice minimum

Today, the Northern Hemisphere sea ice area broke the record for the lowest recorded ice area in recorded history. The new record came a full month before the historic summer minimum typically occurs. There is still a month or more of melt likely this year. It is therefore almost certain that the previous 2005 record will be annihilated by the final 2007 annual minima closer to the end of this summer.

In previous record sea ice minima years, ice area anomalies were confined to certain sectors (N. Atlantic, Beaufort/Bering Sea, etc). The character of 2007's sea ice melt is unique in that it is dramatic and covers the entire Arctic sector. Atlantic, Pacific and even the central Arctic sectors are showing large negative sea ice area anomalies.

[Extremeweatherguy]

This is pretty interesting. However, the only problem I have is that we have only been measuring sea ice since 1979. That is not a very long period on the timeline of the world and really only points to short-term warming mixed with the changing wind patterns they have seen in that region since 1979.

Jeff Masters mentioned this in his blog yesterday: http://www.weatherunderground.com/blog/ ... amp=200708

[x-y-no]

This is pretty interesting. However, the only problem I have is that we have only been measuring sea ice since 1979. That is not a very long period on the timeline of the world and really only points to short-term warming mixed with the changing wind patterns they have seen in that region since 1979.

Jeff Masters mentioned this in his blog yesterday: http://www.weatherunderground.com/blog/ ... amp=200708

That's a valid point. The Navy could help extend that a fair bit if they'd be willing to release their submarine data from the 60's and 70's. Prior to that, we're limited to rather sporadic expeditions.

Of course Dr. Masters also says he thinks we've reached runaway albedo feedback. I think it's possible but I'm not convinced yet.

[jimvb]

What will the effect be on North American weather this autumn and winter? Jeff Masters says we will have a delayed winter - that means above normal weather in October-January, I suppose. How does abnormally warm and moist air in the Arctic Ocean near eastern Russia affect the weather patterns? Will we have warm weather all winter long? Or will we have a normal or cold winter, because we here in North America are on the Canadian Arctic archipelago side of the ice cap, which has stayed the same or even increased slightly? Will it be -20 F in both Chicago and Verkhoyansk?

[xironman]

I don't see and increase Canadian Arctic archipelago side of the ice cap, if you go to http://polar.ncep.noaa.gov/seaice/nh.html you can click the "Ice Cover Same Time Last Year" button, its cool. I found some Canadian data that goes back to the 50's, http://www.socc.ca/seaice/seaice_hist_e.cfm , pretty much more of the same.

[Matt-hurricanewatcher]

On the other hand the sea ice around Antartica has to be above avg. It is huge.

http://arctic.atmos.uiuc.edu/cryosphere ... arctic.jpg

[xironman]

Actually the southern hemisphere ice has been bit above normal for a little while, within its usual range, but it is now back to normal with no anomaly http://arctic.atmos.uiuc.edu/cryosphere ... .south.jpg. If you are on the Cryosphere Today page, http://arctic.atmos.uiuc.edu/cryosphere/ and have a lot of bandwith (188 meg), check out the Quicktime animation of this years melt in the NH, its amazing.

[Matt-hurricanewatcher]

I don't understand why the Antartic sea ice is growing to avg if not above avg. Would it not be decreasing to if the globe was warming?

[x-y-no]

I don't understand why the Antartic sea ice is growing to avg if not above avg. Would it not be decreasing to if the globe was warming?

Two things:

1) The Antarctic is, on average, much colder than the Arctic so the bulk of it is much further from the threshold of melting. Combine that with the heat buffering provided by the south polar sea and the result is less ice loss (particularly in the interior.)

2) A warmer climate means more moisture in the atmosphere which means more precipitation. In the Antarctic region it appears that this extra precipitation is sufficient to maintain something close to ice mass balance.


It's not at all clear that this situation is stable however. Ice flow is an extremely nonlinear process and there's already signs of the ice shelves becoming unpinned, possibly leading to much more rapid flow on average.

[jimvb]

I notice yesterday on NOAA's snow cover Alaska map that ice increased slightly. I looked at forecasts for the Arctic. Iqaluit calls for temperatures to just barely hang above freezing, and Alert is predicted to have below freezing temperatures for a week. To me that's a recipe for more ice.

I had expected the minimum ice to occur on September 10, the marine summer solstice (warmest waters, peak of hurricane season). Maybe the minimum is two weeks early this year. This means a cold winter, not a mild one, although I think it would be mild for Siberia, with all that ice gone.

[xironman]

The Antarctic sea ice is supposed to hold up much better than the Arctic according to the IPCC http://www.grida.no/climate/ipcc_tar/wg2/593.htm. It does look like we are close to the minimum for the year, I get 25% below the last record minimum from Cryosphere Today. That's remarkable, we will see what the actual weather effects are.