An Assessment of Uncertainties in Climate Modelling at the Regional Scale: The Development of Probabilistic Based Climate Scenarios for Ireland

Final Report from EPA ERTDI-funded project 2005-FS-33

Summary: STRIVE Report 48 - Rowan Fealy

STRIVE Report 48 thumbnail

Published: 2010

ISBN: 978-1-84095-345-9

Pages: 78

Filesize: 1,466 KB

Format: pdf


Projected changes in future climate are inherently uncertain. This uncertainty stems largely from 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 do agree that the globally averaged surface temperature will increase due to increasing atmospheric concentrations of greenhouse gases, there is a significant divergence between models in both the spatial and temporal projections of changes in precipitation. These differences are most pronounced at the regional scale. For example, differences are apparent in the magnitude of projected temperature changes between GCMs; for precipitation projections, both magnitude and direction of change can vary between GCMs. Nonetheless, regional scale climate information is necessary if robust adaptation strategies are to be developed.

Until recently, the use of a single climate scenario or climate trajectory was common in the literature. However, reliance on the output from a single GCM means there is significant potential for gross under- or over-estimation of the associated risks, which may result in poor decision-making and increase the risk of maladaptation.

This report presents an overview of the uncertainties that cascade or propagate through the climate modelling framework – from emissions scenarios to subsequent climate projections. It describes a methodology that has been developed for quantifying such uncertainties at the regional scale.

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