Tuesday, 17 March 2015

the 150-year rise in world temperature

It is agreed that world temperatures have risen by some 1.8oC since about 1850,
which is also about the time recording instruments came widely into use. I think
in fact the start of the upward trend could be more correctly put at about 1900.
From then till about 1940 temperatures especially in the Arctic rose markedly,
after which there was a 30-year pause or decline until about 1970, when the
temperature rise began which gave rise to the current widespread concern
about warming.  It is hardly necessary to say that these dates are not exact
and that the start and end dates varied between countries and regions.
                                      The rise since about 1970 can therefore be seen as a
recovery from the exceptionally cold spell of the preceding 30 years, and the rise
from 1850 or 1900 can be seen as a recovery from the exceptional cold of the
Little Ice Age.  Far from being a hockey-stick picture of 1,000 or more years
of temperature stability followed by a steep upsurge in the twentieth century, the
picture is therefore one of continuous fluctuations.
                                       Hubert Lamb  (1913-1997) for long Britain*s leading
climatologist and founder in 1972 of the University of East Anglia*s  Centre
for Climate Research (later hi-jacked by the warmists)  wrote in Climate,
history and the modern world  (Methuen, 1982):
   The cooling of the Arctic since 1950-1960 has been most marked in the very
   same regions that experienced the strongest warming in the earlier decades of
   the present century, namely the central Arctic and the northernmost parts of the
   two great continents remote from the world*s oceans but also in the Norwegian-
   East Greenland sea. In some places e.g. the Franz Josef Land archipelago near
   80oN-60oE, the long-term temperature fell by 3-4 degrees C and the ten-year
   average temperatures became 6 to 10 degrees colder in the 1960s compared with
   the preceding decades.  It is clear from Icelandic oceanographic surveys that
   changes in the ocean currents have been involved, including a greatly (in the
   extreme case, ten times) increased flow of the East Greenland Current, bringing
   polar water southwards. It has in several years, especially 1968 and 1969 but also
   1955, 1975 and 1979 brought more Arctic sea ice to the coast of Iceland than for
   fifty years.  In April-May 1968 and 1969 the island was half surrounded by ice,
   as had not occurred since 1888.
                                       His next paragraph gives an idea of why some warming is
regarded as beneficial, not only in Greenland and Iceland but also in Scandinavia,
Scotland, Canada and Russia  In the first four cold has historically been associated
with famine and emigration.
   Such ice years have always been dreaded in Iceland*s history because of the
   depression of summer temperatures and the effect on farm production. In the
   1950s the mean temperatures of the summer half-year in Iceland had been 7.7
   degrees C and the average hay yield 4.3 tonnes/hectare. In the late 1960s with mean
   temperatures of 6.8 degrees the average hay yield was only 3 tonnes/hectare despite
   the use of more fertilisers. The temperature level was dangerously close to the point
   at which grass virtually ceases to grow. The country*s yield of potatoes was
   similarly reduced.  The 1960s also saw the abandonment of attempts at corn growing
  in Iceland which had been resumed in the warmer decades of the century after a lapse
  of some hundreds of years.
     Further discussion in the author*s THE GLOBAL WARMING DEBATE-  CAN 
SCIENCE PREVAIL?  published by Farsight Research, 1 Wetheral Court, Alston Road,
London SW17 OTS on21st April, 2015, price £18.

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