Reference links :


 A chill from the ocean?

Did the North Atlantic cool down 1968-1972? 
Posted here: 24 September 2010

 Does the science magazine NATURE go for the ‘ocean’ in climatic research matters? A glimpse of hope comes up when reading the paper title: “An abrupt drop in Northern Hemisphere sea surface temperature around 1970”, (23 Sept.2010, Vol. 467). The authors (Thompson et al.[1] ) asses that the twentieth-century trend in global-mean surface temperature was not monotonic: temperatures rose from the start of the century to the 1940s, fell slightly during the middle part of the century, and rose rapidly from the mid-1970s onwards. They conclude, that the “hemispheric differences in temperature trends in the middle of the twentieth century stem largely from a rapid drop in Northern Hemisphere sea surface temperatures of about 0.3°C between about 1968 and 1972”: Does the reference to sea surface temperatures (SST) marks the beginning of a better understanding of what drive the climate? 

The hope stems from a supporting  article by the Nature writer Quirin Schiermeier[2], also in Vol 467, by recognising that “for climate researchers, the discovery that a large patch of the ocean cooled by 0.3 °C within a few years around 1970 is a small sensation.” Both texts have been quickly picked up in the blog-sphere, and to some I submitted comments.


·  2010-09-23 05:47:32 AM , ·  Posted by: Arnd Bernaerts

The research goes in the right direction. The ocean need more attention, and a “large patch” of slightly colder water (0,3°C) in the North Atlantic, can have a similar and a longer lasting effect (from about 1968 - 1972) as an El Nino, or La Nina event in the Central Pacific. What surprises that the researcher seem to assume that they can isolate this few years from the evident NH cooling that started in the early 1940s, in Europe definitely in winter 1939/40, ( ) lasting to the mid 1970s. Since September 1939 “large ocean and sea patches in Europe had been subject to naval war activities, which subsequently covered the North Atlantic and Pacific for four years from December 1941 to summer 1945. SST and SAT dropped for about three decades until the period 1968-1972 which came at the end of the only “global cooling” period since the end of the Little Ice Age (about 1850).

NATURE___(# 14354) 

·  2010-09-23 10:00:20 AM , ·  Posted by: Arnd Bernaerts

RE: Stephen Wilde.  
Cooling and warming is controlled by the ocean, and solar variability has never challenged this control, as over millions of years the global mean temperatures have been kept in a narrow band of a few degrees, which is different from, e.g. , the conditions on the moon due to lack of water.
Even the most prominent known oceanic event, the El Nino, derive presumably from an internal mechanism. Dake Chen et al (Nature, Vol. 428, 2004) assumes:
       “THE implication is that the evolution of major ENSO events is largely determined by oceanic initial conditions, and that the effect of subsequent atmospheric noise is generally secondary.”
Discussed at: Ch.2, p.23f;

One can only hope that the Thompson et al. Nature paper that has been give the attribution of a small sensation is indeed opening a new chapter in climate research, for which I suggested in a letter to Nature almost two decade ago, to define: CLIMATE as the continuation of the oceans by other means.
(NATURE 1992, ‘Climate Change’, Vol. 360, p. 292), in detail discussed at :


26. ArndB, Hamburg, September 23rd, 2010, 8:41 am

# Arno Arrak , Dix Hills,
“It started abruptly at the turn of the twentieth century after a two thousand year, linear, cooling stretch (Kaufman et al., Science 325:1236-1239).”

The date can be given very precisely. It was in winter 1918/19 the temperatures exploded at the Fram Strait and the Spitsbergen region, warming the Arctic  (and NH) for two decades until 1940, presumably caused by warm water from the Gulf Current (West Spitsbergen Current), after having passed Western Europe or the North Sea, which had been subject to devastating naval war activities over a period of four year from 1914 to 1918; see:

The two decades warming was succeeded by a three decade lasting global cool which started in winter 1939/40 and lasted until about the mid 1970s. It surprises that Thompson et al correlate a SST drop in the North Atlantic only towards the end of this period (1968-1972), although there are good reasons to assume that the global cooling since 1940 had, from the beginning, at lot to do with SST changes.  


ArndB says: September 23, 2010 at 6:01 am

# RField says: September 23, 2010 at 4:44 am 

___(1) ”the graph shows a steady warming since 1910”

___(2) ”the drop from 1940” 

(1) The warming during the early 20th Century only started in winter 1918/19 and in the Arctic, although it was felt all over the Northern Hemisphere for two decades until World War II commenced in September 1939. See : , In detail: 

(2) There are many indications that a three decades global cooling started in winter 1939/40, at least in Europe. In 1943 the British scientist A. J. Drummond wrote: “The present century has been marked by such a widespread tendency towards mild winters that the ‘old-fashioned winters’, of which one had heard so much, seemed to have gone for ever. The sudden arrival at the end of 1939 of what was to be the beginning of a series of cold winters was therefore all the more surprising,”
 (in QJoR Met. Society, 1943),  more at:

Even J. Hansen et al (Science, 1981) does not object the mid century cold period : ‘In fact, the temperature in the Northern Hemisphere decreased by about 0.5°C between 1940 and 1970….’. Although there are good reasons to assume that the oceans and seas played a major role in the cooling event since it commenced in winter 1939/40, ,   Thomson et al. identify only the time period from 1968-1972 for a significant oceanic contribution, but which marks only the very end of the global cooling period. This is a far to narrow approach, and any research should cover  the full earth cooling period from 1940 to the mid 1970s. 

[1] David W. J. Thompson, John M. Wallace, John J. Kennedy & Phil D. Jones, Nature 467, 444-447 (23 September 2010); 

[2] Quirin Schiermeier, 22 September 2010,  Nature 467, 381 (2010), „When the North Atlantic caught a chill - Surface cooling could have pushed down temperatures in the Northern Hemisphere 40 years ago.”