The graphs presented below are based on work by many, but
principally that due to Hubert Lamb in " Climate, history and the modern
world ", published in 1982. Work has been done since of course, primarily
(in the UK) at the Met Office Hadley Centre & the University of East
Anglia/CRU, so I have deliberately not copied the diagrams exactly but here
present a broad idea of the rise and fall of temperature and
rainfall so that you can picture the changes in an historical context:
the diagrams may be regarded as up-to-date as of the last 50-yr of the 20th
On the CET graph, I have also shown the actual 50-year values taken from the Hadley Centre series; as you can see, generally they are close to Lamb's ideas.
[ The 'red-filled' star on the right-hand side of the CET graph is the mean temperature for the period 2000 - 2013; this is clearly higher than anything else in this series, but of course is hardly representative of a 'true' 50-year [2000 - 2049] mean. ]
On the EWP graph, I have shown the mean for the 14yr up to 2013: the 'blue-filled' star. The EWP graph shows %-age deviation from the 1961-1990 LTA.
On the diagram are shown, very roughly, the following major climatological periods:
CO: Climatic Optimum (outer limits and peak period)
LMAR: Late Middle-Ages reversal
LIA: Little Ice Age (outer limits and peak period)
MEW: Modern-era warming (rough ideas at this stage) If you want to know more about the England & Wales Precipitation (EWP) or Central England Temperature (CET) series, see the Met Office web site.
The upper graph shows CET & the lower graph EWP since
about 900AD. These actual series of course start relatively recently. It
must be stressed that until the last two to three hundred years, no
instrumental evidence exists for the temperatures & rainfall/snowfall
shown. The record is based on 'proxy' events, built up by relating chronicles
of the times against modern-day values and making a 'best-estimate', or using
ice/sedimentary-cores or tree-rings etc.
On the graph from the late 1200's, some idea of the degree of error is shown within the 'cloud'. Even in modern times, there is much debate about how accurate the temperature record is, bearing in mind that some increase in temperature must be due to urbanisation around the observing sites, and other artefacts following the rapid increase in population since 1950. Although correction factors are used to try and overcome this, we are only talking fractions of a degree C, which may make a major difference when using the series for historical relationships. Similar doubts exist relating to the rainfall series. Please always bear these caveats in mind before declaiming with great fervour a particular line of reasoning based on these data.
The graph below is also based on a diagram published in the work by Lamb (see above). It is useful to see how our current concerns regarding warming relate to some notably warm periods not too long ago, when placed in the context of the current inter-glacial.
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(Last updated November, 2014)