After Jai Mitchell focused my attention on the “Annual Average Thread”, I followed the link and could log in using ‘witsend’s’ keys.
http://witsendnj.blogspot.nl/2014/12/all-about-us.htmlThanks Jai.
Dr. James White makes a clear case on the risks taken by humanity. I somewhat knew the sudden, paleo-climatic events called ‘Dansgaard-Oeschger’. But it was new for me that the ice-cores taken on the GIS can be evaluated now to show what White presented.
That doesn’t completely knock me off, for somehow I suspect the strong temperature shifts presented have a regional signature. They are not necessarily representative for the whole world. Nevertheless, the pic below, taken from the lecture, illustrates how dramatic, though regional events could wind up creating havoc on very short timeframes.
It is not that the content in the lecture is new; in a study published in June ’89 (Dansgaard/White et al) a warming in South Greenland of about 7dC in 50 years was mentioned.
With the newest facilities and more ice-cores from better locations, the score has been precised to mean warming rates of 10dC in 3-5 years (Younger Dryas termination).
Dr. White took all opportunities to explain that this sort of information should be considered in realistic risk assessment. In my own words, there’s a large chance of coinciding, relatively small feedbacks that could trigger this sort of abrupt change. Especially in the present situation.
I have spent hours doing NCEP/NCAR reanalysis correlations on Skin Surface Temps and so on. The idea was to look for clues whether the characteristics of the last two Arctic seasons could tell me anything in context to abrupt change in the form of a Heinrich-/D-O Event? I had the GIS-melt 2012 in mind, though a 500+ Gt loss is small compared to the massive meltwaterpulses that have ended the Weichselien. The loss is even small compared to the yearly freshening in the Arctic Ocean through melt and rivers.
You won’t be surprised that I got no clues. There’s no linear relation to the increased SIE during the summers ’13 and ’14, however, a freshening could have contributed. There’s no clear connection to a decrease in the AMOC (Atlantic Meridional Overturning Circulation), though the last two summers the Barentsz and Kara Seas seem to have reversed in their supposed new Atlantic mode. Comparing winter and summer data from NCEP/NCAR, at least I got a confirmation that more sea ice over there is mainly related to specific weather circulation during summer.
The
weird part (that’s why I chose this thread for the post) in the whole configuration has several sides, in my perception at least.
One is the fledgling Nino event.
Two is worldwide high mean SST’s, over a 1-2 year period, culminating in rising PDO-values.
Three is the complementary/contrary behaviour in SST, wind circulation and sea ice extent around Antarctica.
All these elements tend to suggest that Arctic ice extent- and volume retention ( I wouldn’t call it ‘growth’) is a peculiar, temporally side-effect within a continuing trend.
And while the GHG-forcing passes 400 ppm CO2, I see Dr. White’s lecture as a strong warning that that trend could facilitate a bad surprise. That’s why I regularly suggest a ‘black swan’ event that could lead to an icefree Arctic Ocean sooner than expected.
When? It’s in my eyes impossible to predict. Not by using statistical approaches nor modelling. The correlations and teleconnections are too complex. To get focused attention, worldwide, a sectoral approach based on SIE for instance doesn’t work. There’s too much short term noise.
I hope lectures like the one presented by Dr. White could spread insight in the intricate connections that drive the climate system. The insight should be that the system is now at a stage where relatively small perturbations can have abrupt consequences.
For tonight, though, I wish all of the blogfriends a merry Christmas and some solace in love and friendship.