Comments 1 to 4:

1. nigelj at 06:49 AM on 4 October, 2017

   So the future could bring abrupt climate change. I have a bad feeling that it could. The whole climate system is complex, and hard to fully predict beyond the fact that considerable warming and sea level rise is certain.

   But getting beyond feelings, this abrupt change is apparently based on the evidence that ice ages lead to abrupt changes and ice ages are associated with various feedbacks, so warming could lead to abrupt change through feedbacks as well. The nature of the feedbacks is different, but the big thing changing is the direction of travel. Its hard to see why only ice age feedbacks would cause abrupt change but not warming feedbacks. Why would only ice age feedbacks cause instability and abrupt changes?

   It's interesting that the sub prime crisis was partly caused by poor application of some statistical distribution functions related to risk and stability (gaussian copulas but im not familiar with these whatever they are). Climate scientists are very meticulous, careful, dedicated people but could there be a mistake in the climate modelling equations somewhere that has missed something related to feedbacks, and potential for abrupt change?

   1 0
2. MA Rodger at 19:52 PM on 4 October, 2017

   nigelj @1,

   Climate science is not unaware of the potential for abrupt change. Of course, back in the ice-ages there was more ice sat on more bits of land available to inject fresh water into northern oceans. So, even though their cause is not understood, the chances of a Dansgaard–Oeschger event or a Heinrich event happening today is not a serious consideration. Yet there remains the melt-event described in Hansen et al (2016) which would see this coming century's warming replaced by rapid sea level rise and superstorms. Hansen et al acknowledge they are at variance with IPCC ARs, stating:-
   

   "These predictions, especially the cooling in the Southern Ocean and North Atlantic with markedly reduced warming or even cooling in Europe, differ fundamentally from existing climate change assessments. We discuss observations and modeling studies needed to refute or clarify these assertions."

   Myself, I would say "prediction" is the wrong word to use.

   1 0
3. nigelj at 05:39 AM on 5 October, 2017

   MA Rodger, thanks for the links. I agree prediction is not the best word.

   There still seem to be many unknowns about exactly what caused rapid temperature fluctautions during the ice ages.  The article says essentially that one 'possible' cause is due to the extensive land based ice caps melting and in turn affecting temperatures, and of course theres less ice now to trigger the same things. Hopefully then that was the cause. But there are still unknowns about what really caused the abrupt fluctuations, so we cant be entirely sure such things could not occur in our future.

   No criticism of anyone intended. The research work that has been done is mindboggling and people should read some of it explained in popular science types of articles.

   0 0
4. jja at 05:57 AM on 5 October, 2017

   one of the potential kinds of abrupt changes in atmospheric circulation patterns could be the observed water vapor and heat transport into the arctic beginning with the December 2015 Event and lasting through the winter of 2016

   0 0

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.