Main

Report

Obtaining the Data

Guidance on Using the Data

Climate scenarios are plausible, self-consistent, states of future climate. Climate change scenarios are the changes between current, or recent, climate and a scenario of future climate. The main use of climate change scenarios is in carrying out assessments of the impacts that climate change may have on socio-economic sectors such as infrastructure, agriculture, forestry, water resources and coastal and river flood defences. In this way, adaptation can be planned well in advance, so that damages and costs can be minimised, and parhaps some potential benefits realised.
The use of climate change scenarios for assessing both impacts and adaptation options is a major issue. It is very important that their use is consistent with the purpose of the study and the level of information required to meet that objective. Generally, this is related to the stage reached in the overall assessment process. For a general scoping study, using the four BIC scenarios (High, Medium-High, Medium-Low and Low), or even the highest and lowest, may be adequate to frame the extent of the problem, to decide if a more detailed investigation is necessary. For developing new research methodologies it may even be sufficient to use just one or two scenarios to test the appropriateness of different techniques.

Uncertainty is discussed at some length in this report. Uncertainty in future climate change arises firstly because we do not know how man-made emissions of greenhouse gases will change in the future ("emissions uncertainty"), and secondly because we have an incomplete understanding of how these emissions will change climate ("science uncertainty"). We cope with the first uncertainty by developing four BIC scenarios, as in UKCIP02, covering a wide range of possible future emissions. The science uncertainty cannot be easily estimated as predictions from other suitable models, that could be used to reflect (at least in part) this uncertainty, are not available. However, we have tried to estimate the science uncertainty using predictions from a number of global climate models, and these are illustrated in the report. Natural variability, which leads to significant year-to-year and decade-to-decade variability in climate, will still be superimposed on an underlying man-made trend in future, and adds a further uncertainty. In order to minimise this uncertainty, we calculate changes averaged over 30-year periods; for consistency with UKCIP02, these are centred on the decades of the 2020s, 2050s and 2080s.

For access to scenarios data for the BIC islands are available in numerical form, or for more guidance on using the data, contact details are available here. In parallel with the modelling work, month by month observational data over the island of Ireland at 5km resolution for the period 1961-2000 has been gridded by Met Eireann and is also available on the BIC website, together with data for Jersey and Guernsey (one point on each island). Similar gridded observational data for England, Wales and Scotland (Including the Western Isles, the Orkney Islands and the Shetland Isles) and the Isle of Man are already available from the UKCIP website.