UK Climate Projections (UKCP18) guidance

Guidance on how to use UK Climate Projections (UKCP18) data and products

Introduction 

This page provides UK Climate Projections (UKCP18) guidance documents, reports, factsheets and technical notes to help users know about, understand and utilise UKCP18 data and products.

We have separated the documentation into the following sections:

  1. ‘General UKCP Documentation’ provides background and important information for users of UKCP regardless of the products they choose to use.
  2. ‘Marine Projections Documentation’ details documents specifically for the marine projections,
  3. ‘Land Projections Documentation’ provides information relevant to the land projections products.  

We have also included links to relevant factsheets, journals and other documents towards the bottom of this page (sections 4 and 5). 

If you have any queries about this guidance, please contact the UKCP team.

1. General UKCP documentation

Our UKCP Starters' Guide [PDF document, 30 pages] provides introductory information for new users on the concepts behind the projections, how to choose which information to use, key results, how to access the information, and where to learn more about UKCP18.

For detailed information on the science behind the different components of the projections, see the UKCP Science Overview report (PDF document - March 2019).

Please note the probabilistic projections were updated in August 2022 (see the news update on 4 August 2022), so some figures may have changed since the report was published in March 2019. Additionally, the UKCP Science Overview report does not include information about the Local projections. For this, users should refer to the 'Local (2.2km) projections row' of the table below. For a summary of the different available datasets in UKCP, including how you can access the data, see the UKCP18 Guidance: Data availability, access and formats [PDF document, 16 pages]. 

Users should be aware of caveats and limitations before using the UKCP18 results and data. These are summarised in UKCP18 Guidance: Caveats and limitations [PDF document, 2018].

Further background information for users of UKCP18 can be found in the following documents:

2. Marine projections documentation 

Our UKCP18 Marine Projections report – March 2019 update [PDF document, 4.5MB] provides information about the key findings, caveats and details related to marine projections data. Please note that subsequent updates to the Marine projections are not included in this report. This includes the time-mean sea-level projections update, and the updated sea-level rise and storm surge data. Guidance for both of these can be found below:

Supplementary marine guidance can be found in the following PDF document:

3. Land projections documentation

For a comprehensive description of the underpinning science, evaluation and results, see UKCP18 Land Projections: Science Report - Updated March 2019 [PDF document, 191 pages]. Please note the Probabilistic projections were updated in August 2022 (see the news update on 4 August 2022), so there may be small changes to some of the figures within this report. Additionally, this report does not include information about the Local projections. For this, users should refer to the 'Local (2.2km) projections row of the table below.   

Our UKCP18 Guidance: How to use the UKCP18 land projections - 2018 [PDF document, 20 pages] provides descriptions of the different components of the UKCP18 land projections with examples of how to use them.

For further guidance on specific datasets, refer to the related guidance documents in the table below:

Dataset Description Related guidance document [PDF format]

Probabilistic projections

Probabilistic projections over land
 

Probabilistic projections of climate extremes

Global (60km) projections Global climate model projections
  European circulation indices
Regional (12km) projections A set of 16 high resolution climate projections, at 12km spatial resolution, driven by the global climate model projections.
Local (2.2km) projections A set of 16 high resolution climate projections, at 2.2km spatial resolution, driven by the regional climate model projections.

The latest guidance for the Local projections offers information on unrealistic extreme rainfall features in the data, and how to use the data appropriately as a result:

The following two documents detail the addition of four downscaled CMIP5 members to the UKCP Local ensemble:

In 2023, two additional 20-year time slices (2000-2019 and 2040-2059) were added to the data to provide a full 100 years of data:

In 2021, an update to the Local projections was released, which fixed a code error and made additional science improvements. This data replaced the original UKCP Local data. The following report describes this update:

Our UKCP18 Factsheet: Local (2.2km) Projections (2019) provides background information about convection-permitting models and when they should be used. 

Our UKCP technical note: Issue with UKCP Local (2.2km) simulation data (September 2020) provides details of the code error in the original UKCP Local projections. The issue was resolved and the subsequent versions of the data do not have this issue present.
Derived projections Projections for RCP2.6 and the world, with 2°C and 4°C global warming, produced using statistical methods and based on the global climate model projections.
The table above provides details of the relevant guidance and information documents for each of the UKCP18 land projections products.

4. Factsheets and other documents

Our factsheets below [PDF format] provide information about working with, and results regarding, specific variables or weather types: 

We also have guidance on applying specific techniques to the UKCP18 land projections:

For more technical information on the methods used to produce the UKCP data or assessments of results from the data, see the following PDF documents:

5. Journal publications 

The following online journal publications provide further information on underpinning science of the UKCP projections:

Related links