Today I'd like to draw the attention to the end of the last glacial period. Those who have looked at ice core graphs may recall that the Antarctic ice cores appeared to react first around 17,000 years ago and then with a relative mild change in isotope values (interpreted as temperature change) while the Greenland Ice cores jumped up suddenly with an unprecedent pace around 14,700 years ago, known as the Bolling event (of the Bolling-Allerod twins): http://home.wanadoo.nl/bijkerk/vostok-gisp.GIF So it appeared and was accepted as general paradigm that the southern hemisphere got out the glacial period first, followed by the northern hemisphere, (edit: despite the close correlation between hemispheric temperatures nowadays). However, then it seemed to be time for another ugly fact as in: "The great tragedy of science -- the slaying of a beautiful hypothesis by an ugly fact. (Thomas Huxley). So this study appeared: http://www.sciencemag.org/cgi/content/abstract/312/5779/1510 More elaboration here. Now after the initial shock, let's discuss this abstract. This is very typical and logical development. The first paragraph is the actual description of the study in a nutshell. The results of months of work of obtaining and thorougly processing data with high skill etc. But the result is not what is expected and moreover it challenges one of the most firm paradigms of the ice age, that is that the isotopes of the ice cores reflect the temperatures of the past. So you need an ad-hoc hypothesis in an attempt to harmonize the results being: Now I have not seen the study itself yet and I wonder if this statement is backed by any physical evedence. It could be but I've seen lots of studies where such an hypothesis is also the last sentence of the conclusion not even with reference to (recent) work. So let us investigate the merits of that idea and we find this study, addressing Summer Sea Surface Temperatures (SSST) in de Nordic sea (Greenland Iceland Norway area). I assume that "unusually extensive winter ice" would also have considerable effect on the max possible SSST. After all, freezing and thawing of the sea surface takes a while limiting the time for warming up in the summer time. Hypotheses need predictions. So you would expect low SSST before that Bolling Allerod (14,700-12,800 Calendar years ago). That's essential, then perhaps a sharp increase next matching the ice core spike and a sharp decrease at the onset of the Younger Dryas and finally a sharp increase at the Preboreal some 11,600 years ago. Because that's how science worx, isn't it, verifying the hypothesis by investigating logical predictions. Note, (table 2 on page 5), that the earliest recorded SSST of 13,400 14C BP (is about 16,000 Calendar Years BP) is already a blazing hot 11.6 degrees C compatible with the general modern Holocene values. Not much sea ice there -I would say- at the Norway coastal area well before the onset of the Bolling period around 14,700 Calendar years ago. Furthermore, it’s a bit surprising that the SSST drops down more or less steadily (fig 3 page4) despite the apparant warmth of the Bolling Allerod, well before the assumed cool Younger Dryas. Only one thing is correct of our little predictions, the incredible spike initiated around 11,500 years Calendar years (10,070 14C years), which is consistent with some pet idea. So what is the verdict: Nope, not really. The ocean had warmed already as well before the onset of the Bolling Allerod consistent with the global warming signal of Schaefer et al; actually there is no warming signal at all during that B-A onset more a cooling signal considering the summer sea surface temperutes. As the temperatures go everywhere except where they are thought to go, it would appear to falsify the temperature explanation of the strong Greenland ice core isotope spikes at the last glacial transition. So, there is a whole lot more work to do.