Future projections

Projecting climate change is a complex and ever-evolving science. 

The output of Global Climate Models (GCMs) used to generate projections have a horizontal resolution of between 250 and 600 km. This scale is too coarse for assessing the impact of climate change at a local level. In the diagram below (which gives an indication of the scale and complexity at which GCMs operate), Ireland is represented by just two grid squares.

This is of little use to policy makers and researchers, who need data with a much finer geographical scale to assess aspects such as the future flow regime of a river or the future distribution of an endemic species within a small geographical range. To facilitate such studies, downscaling of GCM outputs to local scales is employed. Two plausible methods of downscaling are dynamical downscaling and statistical downscaling. In ICARUS, statistical downscaling was employed to generate future climate change data for Ireland. For more information on modelling techniques, visit ICARUS here.

High-resolution climate projections for Ireland have been produced using the outputs from global climate models (GCMs), refined by regional climate models (RCMs) (EPA, 2020). A multi-model ensemble approach using a number of GCMs and RCMs was used to allow for the uncertainties in the projections to be quantified. The projections are at a high 4km resolution. The projections are for two different Representative Concentration Pathways, RCP4.5 and RCP8.5, representing moderate and high future emissions scenarios. 

Global Climate Model (GCM)
Climatic Research Unit, School of Environmental Sciences, University of East Anglia, Norwich

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