Home > Climate Impacts > Royal BC Museum Maps

Introduction

Description and Discussion of Methodology

High resolution illustrative climate scenarios were created based on downscaling of low-resolution Global Climate Model (GCM) results using high resolution historical temperature & precipitation observations. The PRISM historical climatology was for BC and surrounding regions. PRISM values are based on interpolations of meteorological observations from a limited number of climate station with a physically-based correction for the effect of altitude.

The climate conditions in each of these small gridboxes were then adjusted to reflect future conditions predicted by GCMs for the 2020s, 2050s and 2080s. A suite of GCMs were used to generate three scenarios representing a combination of different rates of greenhouse gas emissions and model response. The scenarios for each of the time slices may be thought of as optimistic (10th percentile), middle of the road (50th percentile) and pessimistic (90th percentile) projections.

Because GCM grids are several hundred kilometres across, it should be noted that presentation of parameters at 4 km resolution is not meant to imply that future scenarios are accurate to a level that warrants interpretation at such a fine scale. Rather, the broad change from a GCM has been smoothed and used to adjust the high resolution historical climatology (itself with significant uncertainties). This procedure is a useful first approximation for education and visualization purposes, and may be used for "climate envelope" modelling of impacts.

Improved projections could be achieved through more sophisticated downscaling methods, but this was beyond the “educational” objectives of this project. Within the next few years, climate change scenarios derived from several different regional climate models (45 km resolution) will be available. Using these to adjust the PRISM values is expected to improve the results.

Credit: Royal BC Museum, Canadian Institute for Climate Studies, Canadian Center for Climate Modeling and Analysis, UVic Geography, Fortis BC, BC Ministry of Environemnt, Ministry of Forests.