Aug 6, 2014

Dear Mr Battig

Thanks for your request.  You are about the fifth person to ask me
this in the last ten years or more.

What you quote a very abbreviated report of a much longer discussion
at least 22 years ago!  - soon after the 1990 IPCC report and
possibly around the time of the 1992 Supplementary Report.  I cannot
be sure to which sceptical scientist it was made but it may have
been Pat Michaels - and possibly others with him.  Please check with
Pat.

At that time, the key driver for nations' concern about climate
change was indeed mostly driven by model projections of global
warming.  The attached published letter written in an Institute of
Physics journal by myself and one of the then IPCC Working Group 1
coordinators tried to accurately reflect the general view at that
time (1993).  It reflects accurately what I was trying to say the
year or so before.  Please quote these words as appropriate - but
they were only appropriate in the early 1990s.  This view was soon
to change greatly; notice that the letter looks forward at its end
to a greatly increased importance of climate data to the climate
change debate, and to nations' policy actions and concerns.

The situation is now very different and has been since about 1995.
Up to 1993, there were no published detection and attribution
studies.  The situation had changed by the 1995 IPCC report with
the first published detection and attribution studies and since then
the many results of these studies have become the most quoted and
influential aspect of all the IPCC Reports.  Detection and
attribution depends critically on observed climate data as well as
climate models.  It had centre stage of course in the 2001, 2007 and
2013 IPCC reports.  So climate data started to move to centre stage
by the mid 1990s and was definitely right there by 2001 when I was a
convening lead author of the 2001 Report.  Observed data and climate
models are now equally important and vital to each other.  This was
further helped by the fact that in 2001 the first error estimates of
observed global mean temperatures were published (I lead the first
paper) - much been improved conceptually but not greatly changed
quantitatively in recent years - and now available for everywhere
location in the world.  So great efforts continue to go on into
improving data by the leading climate scientists of the world
using ever more advanced statistics.  I, of course, have devoted
considerable time since 1990 to climate data, uncertainties, and
assessing the climate changes, and importantly, the variations, that
they show.

You might notice that some sceptics have a bad habit of quoting, or
going after, very out of date stuff, such as the conceptual curve of
global temperature back to the Middle Ages in the 1990 report, as if
climate science stands still.  Thus another development for which
climate data are essential is the relatively new subject of decadal
to multidecadal prediction (now in the fifth IPCC Report as a stand
alone chapter).  I co-authored the first widely quoted decadal
prediction paper 2007 in Science.  Here I was particularly
responsible for the use of observed data methods to test the
veracity of the early part of these predictions.  Moreover all
decadal prediction models have to be initialised with climate data.
So decadal forecasting is actually impossible without observed
global climate data.  But decadal forecasting did not exist in 1992.

Monitoring of what is happening is clearly essential to see how
climate change and variability are unfolding - such as the current
observed "pause" or hiatus, now that climate predictions have long
been made and need continuously evaluating.  Thus the observed
climate warming "pause" is leading to new insights into climate
variability which will likely eventually lead to improved ability
to make decadal to multidecadal predictions.  Not surprisingly,
the greatly increased interest and range of applications of global
climate data has lead to an explosion in the development of many
kinds of such data sets since the mid 1990s, and developments
continue to accelerate as the observed data now matter very much!.

So climate data are now very much key to the climate change debate
as the attached published letter foretold!  2014 is very different
from 1992!

Please feel free to quote the attached published letter in the
context of the above remarks in any publication - I encourage you
to do this.

I hope this helps

Chris


Professor Chris Folland
Research Fellow
Met Office Hadley Centre
FitzRoy  Road Exeter Devon EX1 3 PB
Tel: +44 (0)1647 432978
chris.folland at metoffice.gov.uk

Hon. Prof. School of Environmental Sciences University of East Anglia

Guest Prof. Faculty of Science Univ. of Gothenburg Sweden

Adjunct Prof. Dept of Sustainable Catchments, Univ. of Southern
Queensland, Australia