enqui
Mr I Dawson
[email address]
request-18647-
Direct tel: +44(0)870 900 0100
[email address]
Direct fax: +44(0)1392 885681
Our ref: 01-10-2009-112121-001
26 October 2009
Dear Mr Dawson,
Re: Environmental Information Regulations enquiry
Your email dated 29 September 2009 has been considered to be a request for information in
accordance with the Environmental Information Regulations Act 2004.
You asked for information relating to our climate prediction paper ‘four degrees’.
The Met Office did present a paper at a conference which demonstrated that global
temperatures may rise by four degrees Celsius relative to pre-industrial, if greenhouse gas
emissions continue at high rates.
The Met Office holds the information and I will answer your questions one by one.
1. How many times was the computer model run?
We ran a total of 796 simulations with our own models specifically for this study, and also
analysed further simulations with models from the IPCC 4th Assessment Report. So a total of
836 simulations were included in this study. This included both full general circulation models
and simple climate models.
2. What other results were obtained?
These models projected a range of levels of global warming by the 2090s. Relative to the pre-
industrial climate, the lowest level of projected warming was 1.9°C by the 2090s, and the
highest was 13.2°C. This range is due to differences in the scenario of greenhouse gas
emissions and differences in the sensitivity of the climate system to a given emissions
scenario – we use multiple models in order to explore this wide range of possibilities.
The extreme projections (in either direction) are excluded as they have a low frequency of
occurrence (it is estimated that the 13.2°C warming by 2090 to occur less than 0.0002% of
time in the 836 simulations.).
Under the high emissions scenario, most simulations projected warming by 4°C or more by
2090. Lower emissions scenarios result in a lower frequency of exceeding 4°C warming,
suggesting that reducing emissions of greenhouse gases could avoid this level of global
warming.
These results are all consistent with work previously published by the Intergovernmental Panel
on Climate Change (IPCC 2007), following a very extensive open peer review process.
3. Did any of the models predict no warming or predict cooling?
No, not in the Pre-Industrial to 2100 temperature change (see response to Question 2).
However for the models which represent internal variability, the models capture periods where
the climate warms faster or slower than the longer term trends. These models all represent
individual periods which cool, which can last up to a decade or more.
4. Was the result that was published the most extreme result obtained?
No, please see the response to Q2
I hope this answers your enquiry.
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Patents Act 1988 (the Act). Unless specifically permitted by the Act, any reproduction of the
information, in whole or in part, requires the permission of the copyright holder. Most
documents supplied by the Ministry of Defence will have been produced by government
officials and will be Crown Copyright. You can find details on the arrangements for re-using
Crown Copyright from the Office of Public Sector
Information at: http://www.opsi.gov.uk/click-
use/index.htm
Information you receive may also include third party owned information. Such information
must not be reproduced, in whole or in part, without first obtaining the permission of any such
third party rights holder.
If you are not satisfied with this response or you wish to complain about any aspect of the
handling of your request, then you should
contact me in the first instance. If informal
resolution is not possible and you are still dissatisfied then you may apply for an independent
internal review by contacting the Head of Corporate Information, 6th Floor, MOD Main
Building, Whitehall, SW1A 2HB (e-mail
[email address]). Please note that any request for
an internal review must be made within 40 working days of the date on which the attempt to
reach informal resolution has come to an end.
If you remain dissatisfied following an internal review, you may take your complaint to the
Information Commissioner under the provisions of Section 50 of the Freedom of Information
Act. Please note that the Information Commissioner will not investigate your case until the
MOD internal review process has been completed. Further details of the role and powers of
the Information Commissioner can be found on the Commissioner's website,
http://www.ico.gov.uk.
Yours sincerely,
FOI Manager
