Climate overview 2007: Hydro-climatology and future climate impacts in British Columbia

Summary

The foundation for understanding the consequences of changing climate (temperature and precipitation) at a regional scale are water resources at the ground level; i.e. hydrology. This requires knowledge of the hydrological regime (rain, snow, ice), hydrological resources (snowpack, glaciers, reservoirs, lakes, wetlands, groundwater and soil moisture), and hydrological processes (interception, evaporation, transpiration, and streamflow). Extremely important water resources responses will result from climate change. Subsequently these responses will influence important economic sectors: power generation, forestry, fisheries, agriculture, mining, and their
commercial derivatives.

The first half of this report presents an updated analysis of BC’s historical climate trends and variability. An interpolated dataset describes the diversity of BC’s climate. Established methods were applied to calculate trends for temperature and precipitation, snowpack, streamflow and lake ice. Trends in glaciers were synthesized from contemporary studies. The response of temperature, precipitation, snowpack and streamflow to climate variability, i.e. the El Niño Southern Oscillation (ENSO)i and the Pacific Decadal Oscillation (PDO)ii is also included in this report.

The second part of the report applies projections of future climate using the latest Global Climate Model (GCM) results from the IPCC Fourth Assessment at a coarse scale. The Canadian Regional Climate Model (CRCM) was also used to obtain climate projections on a regional scale, and empirical methods were used for high-definition mapping in BC. Changes to future snowpack were estimated using a new version of the CRCM. Future climate impacts on glaciers and streamflow were synthesized from select research publications. Examples of future hydrologic impacts, such as soil moisture, changes to growing-degree-days and the Mountain Pine Beetle infestation, were identified.

–Excerpt from the report’s Executive Summary