Scientific advice and evidence in emergencies - Science and Technology Committee Contents

Further supplementary memorandum submitted by the Government Office for Science and the Cabinet Office (SAGE 00b)


Meeting held in Room 35 Great Smith Street, London on 21 September 2010 at 1000.

  Representation from Government: Cabinet Office, Ministry of Defence, Her Majesty's Treasury, Department for Transport, Department of Energy and Climate Change, Centre for the Protection of National Infrastructure, Government Office for Science, Department of Health.

  Representation from the science community: The Rutherford Appleton Laboratory, The British Geological Survey, The Electrical Infrastructure Security Council, The Meteorological Office.

  Representation from the Energy, Communication and Transport Sectors.

  (1)  Introducing the meeting, the Chair said that the purpose of the meeting was to hold an initial exchange of views on the likelihood of severe space weather and possible impacts. The discussion would contribute to the process Government uses to understand risks in this area.


  (2)  The selection of the Carrington Event as the basis for a reasonable worse case solar scenario was discussed. Although much work has been done on the scaling of this event compared to other historical events, the data on which this has been based are limited. A full analysis and use of the Carrington event as a reasonable worst case scenario requires the use of "extreme value statistics" and the currently available data allow only rough and preliminary estimates using this technique. Discussion also centred on different scaling factors used between the UK and the US, because of differences in magnetic latitude. Given these uncertainties, the view of most was that the duration and magnitude of a Carrington event scenario cannot at present be used with high levels of confidence.

  (3)  It was reported that there was a 1% chance of a Carrington-like event occurring during a solar maxima year. The Carrington Event was 150 years ago but the intervening years contain about 30 strong geomagnetic storms of a similar but slightly lower intensity, notably the 1921 storm which damaged telephone networks in Sweden. It was also reported that large geomagnetic storms can be caused by a rapid succession of flare/Coronal Mass Ejections and this has been the case in several important storms. Discussions were held on the increase or decrease in the probability of a severe event in relation to solar maxima and minima years respectively. It was reported that strong solar events can happen at any time, including minima years (eg the 1986 storm), however there is 20 fold increase in likelihood of an event happening during maxima years. Discussions also centred on the robustness of 1% likelihood of a Carrington-like event and whether this was a sufficiently reliable statistic on which to base investment in more resilient technologies.

  (4)  Concerns were raised about the amount of credible data available which could be used to make predictions about future solar events. It was reported that, while UK Flood risk assessment exploits decades of data from similar streams in different catchment areas to construct long statistical datasets (hundreds of years of data), accurate solar data has only been available for the past 40yrs, and with only one source; the Sun within the Solar System. Around 500 years of good recorded data would be needed to estimate 1/100 year events with high degrees of confidence. Ice core readings containing trapped nitrates have provided data which may be used as a proxy of solar radiation storms over the past 400 years, but no proxy yet exists for geomagnetic storms. It was noted that there has been a very strong scientific focus on the Carrington Event in recent years and that other storms should also be considered to construct a reasonable worst case scenario.

  (5)  The direction of solar events was discussed. The impact of a Coronal Mass Ejection (CME) of Carrington magnitude is dependent upon the direction of the ejection and the orientation of its magnetic field, relative to that of the earth. In November 2003, a large CME plumed on the west side of the Sun as seen from the Earth. The effects were far less severe than would be expected had the ejection pointed towards the Earth. If the earth were impacted by a severe solar event, disruption would likely be global. The effects would first be directed to the northern and southern Polar Regions by the geomagnetic field but would rapidly extend to lower latitudes through changes in the upper atmosphere. While a direct event passes earth quickly, magnetosphere instability would last for many days.

  (6)  Impacts on the Communications, Transport and Energy Sectors. There were informal presentations from representatives from the Communication, Transport and Energy sectors on the possible impact on assets in their sectors.

  (7)  International Co-operation. The Meteorological Office is working with the US NOAA (National Oceanic and Atmospheric Administration) Space Weather Prediction Centre to collect space weather information.

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