Temperature and Precipitation indicators of climate change

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El Nino
El Nino is a cyclical phenomenon that occurs every 2 to 7 years when the eastern Pacific Ocean near the coast of equatorial South America becomes unusually warm. That warm water mass generates rising moist air that can disrupt the large scale circulation of the atmosphere, resulting in changes in weather worldwide. During El Nino, BC and Yukon tend to experience warmer and somewhat drier winters. La Nina, which is the opposite phase, results in colder and wetter winters. There have been more frequent and more intense El Nino’s as the global temperature anomalies have increased. This suggests that the regional weather and climate anomalies associated with El Nino may be exacerbated by increasingly higher global temperatures.

Pacific Decadal Oscillation
The Pacific Decadal Oscillation is a regular 20-30 year cycle in ocean temperatures in the mid-latitude North Pacific basin. The cool and warm phases of the oscillation have had a discernible influence on the climate of western North America over the past century. The 20th century began with cooler annual temperatures from about 1900 to 1925 (cool phase) which were followed by warmer temperatures from about 1925-1945 (warm phase). Cooler temperatures again predominated between 1945-1975 (cool phase), followed by a resumption of warmer temperatures in the last quarter of the 20th century.

Statistical Significance
For a temperature trend to be significant in a statistical sense, the change in temperatures or trend, must be greater than the year to year level of random variability for a particular station. Statistical significance is computed for each station's trend-line. When the probability of this trend occurring randomly is less than 10% (or P<0.10) then the trend is statistically significant at the 90% level. Similary for the following probabilities: when it is less than 5% (P<0.05) the trend is significant at 95% level, when it is less than 1% (P<0.01) the trend is significant at 99% level and when it is less than 0.1% (P<0.001) the trend is significant at the 99.9% level.

Growing Season
The beginning of the growing season in this example is when the average daily temperature has risen consistently above 5 degrees Celsius for about a month, allowing the soil to become sufficiently warm for seed germination. The beginning of summer is when the temperature rises consistently above 10 degrees C for about a month. The end of the growing season is when the average daily temperature drops below 5 degrees for a few days, triggering many plants to become dormant. Similarly, the end of summer is when the temperature drops below 10 deg.C for a few days.

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Data Set for Climate Stations

The 58 climate stations in the following table were chosen for representativeness of climatic regions, record length and record completeness. All data used were extracted from Environment Canada's Adjusted Historical Canadian Climate Database. The data has been quality controlled and adjusted to correct for non-climate related changes due to things like station relocation and instrument changes. Note: the Pacific and Yukon Region is divided into four defined climatic regions: Pacific, South BC Mountains, Yukon/North BC Mountains and the Northwestern Forest. The former two fall entirely within BC while only parts of BC form part of the latter two regions. All of the Yukon is in the Yukon/North BC Mountains region. Six climate stations outside of the Pacific and Yukon Region (four from the Northwest Territories [NWT] and two from Alberta) were added to the trend analysis in order to help complete and extend the trend contours within the BC/Yukon region.

Source: Environment Canada. 2004. Adjusted Historical Canadian Climate Database.

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Maximum and Minimum Temperature, Precipitation and Frost Free Days Trend Data Analysis

The following table provided the seasonal and annual trend analysis results of the 1950-2001 climate data of the 58 selected regional climate stations. The statistically significant trends are indicated in bold font.

Note that: The trend analysis is limited to the 52 year (1950-2001) period due to data gaps and a general lack of data at many stations prior to the 1950's. Trends in frost free days were, of necessity, calculated from daily minimum temperature data. This daily data was obtained from the Environment Canada's Adjusted Historical Canadian Climate Database. All trends are calculated using an Excel template MAKESENS version 1.0 (2002). This MAKESENS software uses a non-parametric Mann-Kendall test for trend and Sen's linear slope estimates. In addition, prior to trend calculation the data are adjusted for autocorrelation using the prewhitening method of Wang and Swail, 2001.

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Temperature, Precipitation and Trend Analysis of 15 Selected Regional Climate Stations

The following are the seasonal and annual trend analysis results of the 1950-2001 climate data of 15 selected climate stations. They are displayed in a table for each climate station and statistically significant trends are indicated in bold font. This is followed by graphical presentation of the historical seasonal maximum and minimum temperatures and precipitation data expressed as departure from the 1961-1990 average. For more on the methodology see the above table on trend analysis.

Prince Rupert Airport, British Columbia

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Quatsino, British Columbia

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Cape St. James, British Columbia

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Victoria International Airport, British Columbia

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Kamloops Airport, British Columbia

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Summerland, British Columbia

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Cranbrook Airport, British Columbia

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Golden, British Columbia

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Prince George Airport, British Columbia

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Fort St. John, British Columbia

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Fort Nelson Airport, British Columbia

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Dease Lake, British Columbia

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Watson Lake Airport, Yukon

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Whitehorse Airport, Yukon

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Dawson City Airport, Yukon

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References Used for this Indicator:
Note: Some of the following hyperlinked material originates from an organization not subject to the Official Languages Act. It is made available on this site in the language in which it was written. You will need to download the Adobe Acrobat Reader to access certain links (.pdf) on this page.

• Arctic Climate Impact Assessment. 2004. Impacts of a Warming Arctic. Cambridge University Press, Cambridge, UK. (See http://www.acia.uaf.edu/).
• BC Minisrty of Water, Land and Air Protection (BCWLAP). 2002. Indicators of Climate Change for British Columbia, 2002. Victoria, British Columbia. 48pp. ( http://wlapwww.gov.bc.ca/air/climate/indicat/index.html).
• Bertram, D.F., D. Mackas and S. McKinnell. 2001. The seasonal cycle revisited: Interannual variation and ecosystem consequences. Progress in Oceanography. In Press.
• Beyond the breaking Point? Why Canada must have a strong government research infrastructure to address environmental threats such as climate change, air pollution, and severe weather. 2004. Meteorological Society of Canada, Toronto, Ontario(?).
• Bruce, J.P., I. Burton and I.D. Mark Egener. 1999. Disaster Mitigation and Preparedness in a Changing Climate. A synthesis paper prepared for: Emergency Preparedness Canada, Environment Canada and the Insurance Bureau of Canada. Global Change Strategies International Inc.
• DFO, 2001. 2000 Pacific Region State of the Ocean (report pdf. format 3515 Kb). DFO Science Ocean Status Report 2001-01 (2001).
• Dore, M.H.I. 2003. Forecasting the conditional probabilities of natural disasters in Canada as a guide for disaster preparedness. Natural Hazards 28: 249-269.
• Easterling, D.R., Briony Horton, Philip D. Jones, Thomas C. Peterson, Thomas R. Karl, David E. Parker, M. James Salinger, Vyacheslav Razuvayev, Neil Plummer, Paul Jamason, Christopher K. Folland. 1997. Maximum and Minimum Temperature Trends for the Globe. Science Vol. 277, No. 5324, 18 July 1997.
• Environment Canada. 2004. Canada's Greenhouse Gas Inventory, 1990-2002. Ottawa, Ontario. 254p. (The document is available on Environment Canada's green Lane at http://www.ec.gc.ca/pdb/ghg.)
• Environment Canada. 2003a. Information on Greenhouse Gas Sources and Sinks, Ottawa, Ontario. (Report available at http://www.ec.gc.ca/pdb/ghg/ghg_home_e.cfm).
• Environment Canada. 2003b. Natural Disasters on the Rise. The Science and the Environment Bulletin, March/April 2003. Ottawa, Ontario. (Available at http://www.ec.gc.ca/science/sandefeb03/a3_e.html.)
• Environment Canada. 2001a. Tracking Key Environmental Issues. Ottawa, Ontario. 59p. (Report available at http://www.ec.gc.ca/tkei/main_e.cfm.)
• Environment Canada. 2001b. Canada's greenhouse gas inventory, 1990-1999: emission and removal estimation practices and methods. Ottawa, Ontario. 98p. (The inventory follows a detailed, comprehensive and consistent approach as per the recently agreed United Nations Framework Convention on Climate Change Common Reporting Format (CRF). The methodologies used to establish the estimates are also consistent with the International Panel on Climate Change (IPCC). The total greenhouse gas emission estimates are derived from a detailed inventory of the energy, industrial processes, solvent and other product use, agriculture, land use change and forestry, and waste sectors.)
• Etkin, D., E. Haque, L. Bellisario and I. Burton. 2004. An Assessment of Natural Hazards and Disasters in Canada - A Report for Decision-Makers and Practitioners. Public Safety & Emergency Preparedness Canada and Environment Canada. Ottawa, Ontario.  
• Etheridge, D.M., L.P. Steele, R.L. Langenfelds, R.J. Francey, J.-M. Barnola and V.I. Morgan. 1998. Historical CO2 records from the Law Dome DE08, DE08-2, and DSS ice cores. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.
• IPCC, 2001. Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) J. T. Houghton, Y. Ding, D.J. Griggs, M. Noguer, P. J. van der Linden and D. Xiaosu (Eds.) Cambridge University Press, UK. pp 944.(Summary for Policymakers .pdf format).
• Intergovernmental Panel on Climate Change Second Assessment Report, 1995. Climate Change 1995: The Science of Climate Change. Contribution of Working Group I to the Second Assessment of the Intergovernmental Panel on Climate Change. JT Houghton, LG Meira Filho, BA Callender, N Harris, A Kattenberg and K Maskell (Eds) Cambridge University Press, UK. pp 572. (Summary for Policymakers).
• Keeling, C.D. and T.P. Whorf. 1999. Atmospheric CO2 records from sites in the SIO air sampling network. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge, Tenn., USA
• Mekis, Éva and William D. Hogg, 1999: Rehabilitation And Analysis Of Canadian Daily Precipitation Time Series. Atmosphere-Ocean 37(1) 1999, 53-85.
• Metcalfe, J.R., B. Routledge and K. Devine, 1997: Rainfall measurement in Canada: changing observational methods and archive adjustment procedures. J. Climate, 10, 92-101.
• Neftel, A., H. Friedli, E. Moor, H. Lötscher, H. Oeschger, U. Siegenthaler, and B. Stauffer. 1994. Historical CO2 record from the Siple Station ice core. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge, Tenn., USA
• Neitzert, F., K. Olsen and P. Collas. 1999. Canada's Greenhouse Gas Inventory: 1997 Emissions and Removals with Trends. Environment Canada, Ottawa, Ontario. 149p.
• Leith, R.M.M. and P.H. Whitfield. 1998. Evidence of Climate Change Effects on the Hydrology of Streams in South-Central BC Canadian Water Resources Journal. Vol. 23 (3):219 - 230.
• Pacific Fisheries Resource Conservation Council. 2000. Annual Report 1999 - 2000. Vancouver, BC. 
• Pacific Fisheries Resource Conservation Council. 2000. Annual Report 1999 - 2000 Chapter 4 Climate Change Issues. Vancouver, BC.
• Taylor, E and B. Taylor (eds.). 1997.  Responding to Global Climate Change in British Columbia and Yukon. Volume 1 of the Canada Country Study: Climate Impacts and Adaptation. Environment Canada and BC Ministry of Environment, Lands and Parks. Vancouver, BC.
• United Nations Environment Program (UNEP). 2002. Climate Change and the Financial Services Industry. Module 1 - Threats and Opportunities. Prepared for UNEP Finance Initiatives Climate Change Working Group by Innowest Strategic Value Advisors. 36p.(see http://www.sefi.unep.org/).
• Vincent, L.A., 1998: A technique for the identification of inhomogeneities in Canadian temperature series. Journal of Climate, 11, 1094-1104.
• Vincent, LA, and D. W. Gullett, 1999: Canadian historical and homogeneous temperature datasets for climate change analyses. International Journal of Climatology, 19, 1375-1388.
• Wang, X.L., and V.R. Swail, 2001. Changes in extreme wave heights in Northern hemisphere oceans and related atmospheric circulation schemmes. J. Climate 14: 2204-2221.
• Whitfield, P.H., and E. Taylor. 1998. Apparent Recent Changes in Hydrology and Climate of Coastal British Columbia. In: Y. Alila [ed] Mountains to Sea: Human Interaction with the Hydrologic Cycle. Proceedings of 51^st Annual Canadian Water Resources Conference. PP 22-29.
• World Meteorological Organization (WMO). 2004. WMO Statement on the Status of the Global Climate in 2003. (See http://www.wmo.ch/web/wcp/wcdmp/statement/html/statement.html).

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