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Project title

Coping with uncertainties in climate modelling for Ireland

Primary Funding Agency

Environmental Protection Agency

Co-Funding Organisation(s)

n/a

Lead Organisation

Maynooth University (MU)

Lead Applicant

Rowan Fealy

Project Abstract

Projected changes in future climate are inherently uncertain. This uncertainty largely arises due to the fact that even for a specified emissions scenario global climate model (GCM) simulations result in a range of plausible scenarios being modelled. While most models agree that the globally averaged surface temperature will increase due to increasing atmospheric concentrations of greenhouse gases significant divergence between models occurs in both the spatial and temporal projections of changes in precipitation. Such differences are most pronounced at the regional scale. For example differences are apparent in the magnitude of projected temperature changes between GCMs while for precipitation projections both magnitude and direction of change may vary between GCMs. Yet it is regional scale climate information that is required in order to develop robust adaptation strategies. This report presents an overview of the uncertainties that cascade or propagate through the climate modelling framework from emissions scenarios to subsequent climate projections and develops a methodology for quantifying such uncertainties at the regional scale. Initially a methodology adopted from the dynamical modelling community was employed to i'pattern scalei previously downscaled A2 and B2 scenarios to the A1FI and B1 emissions scenarios for selected locations in Ireland. This step enabled a quantification of the projected changes in temperature and precipitation for the end of the present century across the four marker emissions scenarios (A1FI A2 B2 and B1).The projected changes in temperature and precipitation for each station and season were then normalised by the parent GCM/emission scenario change in the global mean surface temperature change (T) to produce regional response rates per oC global warming. The range in values of the regional response rates for temperature and precipitation were assumed to reflect the uncertainty in global climate model output at the regional/station level. As no likelihoods could be attributed to the values within the identified ranges a uniform probability distribution was initially assumed as representative of the regional response rates for both temperature and precipitation.

Grant Approved

�175,098.92

Research Hub

Climate Change

Research Theme

Ireland's Future Climate, its Impacts, and Adaptation Options

Start Date

01/10/2006

Initial Projected Completion Date

01/10/2008