11 SRESA1B: IPCC future scenario based on rapid economic growth and a balance of energy sources
12 30-year means can be created using the UKCP18 PDF data
13 http://www.euro-cordex.net/
60KM GLOBAL PROJECTIONS 
20 plausible climate futures. Latest Hadley Centre climate model. Simulations 
of extreme weather. Simultaneous impacts captured at multiple locations.
This resolution will enable more realistic simulations of climate for the UK and capture the 
drivers of extreme weather, a significant advance on the 300 km-resolution simulations of 
UKCP09.  A set of 20 plausible global projections of 21st century climate will be generated 
using an ensemble of the Met Office Hadley Centre HadGEM3 climate model.  These 
projections will be selected to represent a wide range of possible future climate states 
to reflect key uncertainties, informing a risk-based approach to planning.  They will be 
generated to provide spatially coherent daily data at a horizontal resolution of 60 km for 
two greenhouse gas concentration scenarios. These will be compared with an ensemble of 
CMIP5 models to provide additional information on uncertainties in the projections relative 
to other climate models.
25KM PROBABILISTIC PROJECTIONS  
Captures natural variability and climate change . Updated models  and 
observations. Provides seasonal  scale projections.
Based on the established, peer-reviewed, ground-breaking method of UKCP09 for 
estimating uncertainty for use in risk-based analysis.  Probabilistic projections will be 
updated using an up-to-date collection of Met Office climate simulations and the latest 
IPCC-assessed simulations to estimate the model uncertainties, incorporate the latest 
observations and estimate carbon cycle feedbacks.  Projections will be on a 25 km grid for 
the UK at monthly intervals for several emission scenarios, including one used in UKCP09
11.  
The new probabilistic projections will indicate the range of uncertainty in our knowledge 
of the climate system and natural variability through the 21st century, using probability 
density functions to provide information on how climate varies from month to month.  This 
contrasts with UKCP09 for which only 30-year means were provided
12.
DOWNSCALED HIGH RESOLUTION PROJECTIONS 
Downscaled versions of the  global model for the UK.  For the most spatially 
detailed  downscaling this includes  hourly data. Simultaneous  impacts captured 
at  multiple UK locations.
The high resolution projections will provide information on types of weather of relevance 
to adaptation at two different resolutions.  The 12 km model provides a downscaled 
product that is similar to UKCP09’s 25 km simulations but driven by an improved global 
model and at a higher resolution.  This may be especially useful for those interested in 
water availability and some aspects of agriculture.  A key reason for providing this data is 
that users will be able to compare it directly with EURO-CORDEX
13.         
The global projections will also be downscaled to 2.2 km using a process of nesting 
models at finer resolution that maintains the integrity of the representation of evolving 
atmospheric processes.  Key benefits of simulations at this resolution will be the 
information provided on high impact events such as localised heavy rainfall in summer and 
potential improvements in the diurnal cycle.   
The output will be available at a time resolution of 3-hourly, possibly higher for some 
output, for a high emission scenario. Spatial coherence will be maintained.  Specific time 
slices (e.g. 2061-2080) will be made available with the exact nature of these still to be 
confirmed.
PROJECTIONS OVER LAND 
The land projections comprise three components: