The last 1000 or so years .. temperature & rainfall over 'southern Britain'

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 (principally 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 century.
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 the Lamb ideas.
On the EWP graph, I have also shown the mean for the 10yr up to 2005; this 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.

Holocene temperature profile in 'middle' England

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.

(Last updated September, 2010)