Preliminary Analysis of Climate Change in the Cariboo-Chilcotin Area of British Columbia 08 September 2008 R.J. Dawson A.T. Werner, PCIC Ministry of Agriculture and Lands T.Q. Murdock, PCIC Preliminary Analysis of Climate Change in the Cariboo-Chilcotin Area of British Columbia 08 September 2008 R.J. Dawson A.T. Werner, PCIC Ministry of Agriculture and Lands T.Q. Murdock, PCIC (BLANK) Citation: Dawson1, R., A.T. Werner2, T.Q. Murdock2, 2008: Preliminary Analysis of Climate Change in the Cariboo-Chilcotin Area of British Columbia. Pacific Climate Impacts Consortium, University of Victoria, Victoria BC, 49 pp. 1Integrated Land Management Bureau, 2Pacific Climate Impacts Consortium ACKNOWLEDGEMENTS This report draws heavily on work done by the Pacific Climate Impacts Consortium (PCIC) with the support of the Columbia Basin Trust (Murdock et al., 2007). Additional maps and data of past and future climate for the Cariboo-Chilcotin were prepared by PCIC specifically for this project with the support of the BC Ministry of Agriculture and Lands, Integrated Land Management Bureau. Environment Canada data was used for the historical climate analysis. The Canadian Regional Climate Model (CRCM4) outputs used to produce the mapped projections in this report were provided by the Ouranos Consortium in collaboration with the Canadian Centre for Climate Modelling and Analysis of Environment Canada. Figures 1-2 and 2-1 were included with the permission of Dr. Van den Dool and Rick Lee respectively. Tim Kittel, Research Affiliate with the Institute of Arctic and Alpine Research (INSTAAR) from the University of Colorado at Boulder, provided a very useful review. i (BLANK) Table of Contents Acknowledgements ......................................................................................................................................... i Executive Summary........................................................................................................................................ 1 1 Introduction ................................................................................................................................................. 3 1.1 Purpose .............................................................................................................................................. 3 1.2 Description of the Cariboo-Chilcotin Area ....................................................................................... 3 1.3 Global and Canadian Context of Climate Change ............................................................................ 4 1.4 Overview of the Report ..................................................................................................................... 6 2 Climate Concepts, Terms and Measurement .............................................................................................. 7 2.1 Climate Time Scales, Concepts and Terms ....................................................................................... 7 2.1.1 Climate and Weather .............................................................................................................. 7 2.1.2 Important aspects of climate variability and climate change .................................................. 8 2.1.3 Extreme weather events and climate change ........................................................................ 11 2.2 Measuring and Analyzing Historical Climate ................................................................................. 11 2.2.1 Paleoclimate ......................................................................................................................... 11 2.2.2 Historical Weather Measurements and Climate.................................................................... 11 2.2.3 Analysing Historical Climate Trends ................................................................................... 12 2.3 Projections of Future Climate ......................................................................................................... 15 2.4 Continuing Emergence of Climate Information .............................................................................. 16 3 Climate Change in the Cariboo-Chilcotin: Past Trends and Future Projections ....................................... 17 3.1 Baseline Climate for the Cariboo-Chilcotin .................................................................................... 17 3.1.1 1961-1990 Station Climatology Data ................................................................................... 17 3.1.2 1961-1990 Climatology Maps .............................................................................................. 18 3.1.3 Climate Variability ............................................................................................................... 21 3.2 Historical Climate in the Cariboo-Chilcotin.................................................................................... 24 3.2.1 Summary ............................................................................................................................... 30 3.3 Future Climate in the Cariboo-Chilcotin ......................................................................................... 31 3.3.1 Global Climate Model Projections ....................................................................................... 31 3.3.2 High Resolution Regional Climate Model Projections ......................................................... 32 3.3.3 Temperature .......................................................................................................................... 33 3.3.4 Growing Degree Days .......................................................................................................... 36 3.3.5 Precipitation and Snowpack ................................................................................................. 37 3.3.6 Summary ............................................................................................................................... 40 4 Potential Impacts Of Climate Change In The CCLUP Area ................................................................... 42 5 Next Steps ................................................................................................................................................ 43 6 References and Suggested Reading ......................................................................................................... 45 ii LIST OF TABLES Table 2-1 − Temperature measures ............................................................................................................. 12 Table 2-2 − Precipitation measures ............................................................................................................. 12 Table 3-1 − 1961-1990 baseline temperature data for three stations in the Cariboo-Chilcotin ................... 17 Table 3-2 − 1961-1990 baseline precipitation and snow depth for three stations in the Cariboo-Chilcotin 18 Table 3-3 − Climate trends for three Cariboo-Chilcotin weather stations 1950-2001. ................................ 26 Table 3-4 − Climate trends for Prince George and Kamloops 1950-2001. ................................................. 30 Table 3-5 − Mean growing degree days (5°C base) for selected stations in the B.C. Interior in 1961-1990. 36 LIST OF FIGURES Figure 1-1 − Glaciers, ice fields and major watersheds in the Cariboo-Chilcotin ......................................... 4 Figure 1-2 − Global mean temperature change by decade from the 1950’s to the 2000’s versus the mean for the 1950 to 2000 period (used with permission from Dr. Van den Dool, see Fan and Van den Dool, 2008 for methodology). ................................................................................................................................... 5 Figure 2-1 − Time and spatial scales of weather and climate ........................................................................ 8 Figure 2-2 − Time scales of climate variability and climate change ............................................................. 9 Figure 2-3 − Monthly Average Values for the Niño ENSO Index. Positive (red) index values indicate an El Niño event. Negative (blue) values indicate a La Niña event. .................................................................. 10 Figure 2-4 − Mean temperature trends for Canadian portion of the Columbia Basin for (a) 50-year trends and (b) 30-year trends. From Murdock et. al. 2007. ...................................................................................... 14 Figure 3-1 − Baseline map of mean annual temperature for the Cariboo-Chilcotin (1961-1990). .............. 20 Figure 3-2 − Baseline map of mean annual precipitation for the Cariboo-Chilcotin (1961-1990). ............. 21 Figure 3-3 − Historical effects of ENSO and PDO on winter temperature in the Cariboo-Chilcotin. ......... 22 Figure 3-4 − Historical effects of ENSO and PDO on winter precipitation in the Cariboo-Chilcotin. ........ 23 Figure 3-5 − Quesnel mean annual temperature trend 1895-2004 and 1950-2001. Both trends are significant at the 95% confidence level (p<0.05). ......................................................................................... 25 Figure 3-6 − Tatlayoko mean annual temperature trend 1930-2004 (not significant) and 1950-2001 (significant at the 95% confidence level, p<0.05). ........................................................................................ 25 Figure 3-7 − Quesnel average January minimum temperature