Observed and modelled near-surface and, in
particular, upper-air temperature datasets for the
latter part of the 20th Century are considered in
an attempt to yield the most likely explanation of
recent climate changes. This is achieved through a
suite of increasingly complex detection and
attribution approaches culminating in a
consideration of the spatio-temporal evolution of
a range of tropospheric temperature parameters. In
this latter study, a first attempt is made to
advance towards making meaningful assessments of
model adequacy. For all approaches employed, the
most likely explanation of the observed trends
arises through a consideration of anthropogenic
forcings, although there is additional evidence
for a volcanic effect. In all cases numerous
sensitivity studies are undertaken in an attempt
to ensure against making ambiguous conclusions.
Taken together along with the consistency of
results herein with those of previously published
studies, this leads to increased confidence in the
presence of a demonstrable anthropogenic influence
on recent climate. Furthermore, the analysis here
is unable to definitively prove that the two
models considered are inadequate explanations of
the observations during the period considered.
However, caution is advised against making more
meaningful statements until the degree of adequacy
can be explicitly quantified.

Results detailed in this thesis are critically
dependent upon the veracity of the observed and
modelled fields. Analysis of the results implies
that corrections made to the observed upper-air
temperature dataset employed here are sub-optimal
in considering solely temporal consistency
aspects. In restricting corrections to a temporal
aspect alone, it is likely that some of the
corrections move the dataset away from the
principal spatio-temporal modes of atmospheric
variability. Additionally, strong evidence was
found for gross residual errors, which were
removed prior to the detection and attribution
analyses. Scope remains for development of more
optimally derived observed upper air temperature
products.