Updates

10th February 2003
1. A table is available, accessible via 'Data' on the left frame, that summarises the full range of data-sets available.
2. A new country-by-country climate data-set has been added, presenting information on modelled climate changes during the 21st century. See TYN CY 3.0.

21st August 2002
The Climatic Research Unit and the Tyndall Centre are currently re-organising the dissemination of data-sets. As part of this re-organisation, related data-sets are being labelled under a consistent scheme of acronyms. We urge users of these data-sets to use these acronyms wherever possible, to enable the data-sets that they have used to be identified clearly and unambiguously. This data-set is now labelled TYN CY 2.0.

19th August 2002
1. A page has been added giving examples of published academic work that uses the country climate data-sets. I welcome the opportunity to add details of your work (see the page for details)!
2. I have added an electronic version of the paper describing the observed country climate data, which was published in a peer-reviewed journal called Area.

23rd May 2002
Data-set released giving an indication of future climate changes for individual countries. This new data-set has not yet been approved by the IPCC-DDC; therefore it does not constitute part of the IPCC-DDC website, nor is it recommended for use by the IPCC-DDC, unlike the observed data in TYN CL 1.0.

Introduction
The data set described here provides a summary of some of the possible changes in climate that may be experienced during the 21st century in 289 countries and territories.

• Two variables are included: temperature change (degrees Celsius) and precipitation change (percentage).
• Two seasons are included: December-February (DJF) and June-August (JJA).
• Two emissions scenarios are included: A2 and B2 from the IPCC SRES scenarios (see IPCC or IPCC-DDC websites).

Guidance

The purposes for which this data-set are relevant differ from the purposes of the observed data-set (TYN CL 1.0). The primary purpose here is to permit an assessment to be made of the plausible extent of climate change over the 21st century, driven by anthropogenic emissions of greenhouse gases and sulphur dioxide. It is reasonable to do this at the spatial scale of individual countries because the spatial scales at which climate change may occur (as measured here) are much larger than the spatial scales of the climate itself (as measured in the observed data-set.)

However, a number of caveats should be noted.

• The climate models shown here do not explicitly recognise the smaller countries within their grids.
• Since climate changes may depend on elevation, not just latitude and longitude, these models (which only represent elevation on scales of hundreds of kilometres) may misrepresent climate changes in smaller countries at high elevations.
• Where a country includes a number of different climatic regions (i.e. regions in which climate varies coherently), it is possible that the models may represent the changes accurately in each region, but that the average change over the country as a whole may not be physically meaningful.

Data Structure
The information is available for each country in two forms: as a graphic file (.pdf) and as a data file (.txt). These files are presented in a table, with the data files ordered alphabetically by country.

To make it easier to combine this data-set with the observed data-set in trans-boundary studies, the same data-set is also available with all the countries in consolidated files, presented in a different table.

Disclaimer
The author bears no responsibility for the accuracy of the data set. The countries listed below include a variety of sovereign states, dependent territories, and disputed territories. No political statement is being made by the inclusion or exclusion of a particular territory, or by the labelling of a particular territory by a particular name.

Data Processing
The original data were provided to Dr. Richard Jones (Hadley Centre) on each model's native grid. Dr. Jones regridded the data to a common grid (144 cells longitudinally, 73 cells latitudinally). This author then regridded the data onto a 0.5 degree grid. We then used the allocation of grid cells to individual countries developed for the observed data (see below) to aggregate grid cells into countries.

The method of allocating countries was as follows. We assigned each box to a single country. For each country we calculated the weighted mean of the values from its constituent grid boxes for each month in turn. Each grid box was weighted by surface area, using the cosine of the latitude. For further information see the paper published in Area (electronic version here).

Models
The nine climate models used here are the set of models used by the IPCC (2001) in the Third Assessment Working Group 1 Report. Further details about the individual models may be obtained from that report (Tables 8.1 and 9.1).