Change in Sea Surface Temperature in B.C. (1935-2014)
Change in ocean temperature is an important measure of marine ecosystem health and productivity. Long-term change in this measure is likely to affect marine species and ecosystems and the human communities and resource industries that depend on the sea. This indicator measures changes in average sea surface temperature in degrees Celcius (°C) per century. Results are provided annually and seasonally for seven locations along the B.C. coastline.
- Sea surface temperatures have warmed significantly from 1935 to 2014 in B.C. Warming trends in annual average sea surface temperature varied from 0.6°C per century for Kains Island to 1.4°C per century for Entrance Island.
- Seasonal sea surface temperatures have warmed significantly at some stations and seasons and not significantly for others. Seasonal warming trends range from 0.7°C per century at Race Rocks in winter to 2.2°C per century for Entrance Island in summer.
- No trend in sea surface temperature was detected at Departure Bay. The lack of trends for any season at Departure Bay contrasts with results from other stations that reveal a significant trend in at least one season of the year. However, the Departure Bay station, near Nanaimo, is in a location of limited tide mixing with strong influences from nearby freshwater outfalls.
Observed Change in Sea Surface Temperature (1935-2014)
Sea surface temperature in B.C.'s coastal waters increased during the last century.
Observed Change in Seasonal Sea Surface Temperature (1935-2014)
Interpreting the Trend Information:
- This assessment was conducted by the Pacific Climate Impacts Consortium using data from Fisheries and Oceans Canada.
- Sea surface temperature is measured manually at light stations along the British Columbia coastline. Measurements are taken at the first daily high tide using a collection bucket and thermometers.
- Seven light stations in B.C. have a sufficient data record for long-term sea surface temperature trend analysis.
- Results were found to be significant at the 95 percent level. This means that there is a less than 5 percent probability that the results arose randomly.
- Where the data fail to reveal a trend that is statistically significant at the 95 percent level, data are annotated with an "NS" to indicate that the trend is not significant.
More About Sea Surface Temperature
- The Intergovernmental Panel on Climate Change (IPCC) suggests that average global sea surface temperature has increased at a rate of 1.1°C per century between 1971 and 2010. The rate of warming along the west coast of Vancouver Island—the coastal area most exposed to trends in the Pacific Ocean—is similar to the global average.
- Sea surface temperature will likely continue to vary from year to year and from decade to decade in response to natural cycles. Climate models project, however, that the Earth will continue to warm and that average global sea surface temperature will increase by 0.6°C to 2°C in the top 100m of the sea by the end of the 21st century.
The methods used to develop this indicator and more about change in sea surface temperature and other climate indicators are available in Indicators of Climate Change for British Columbia (2015-16 Update) (PDF, 4.5MB). The R code for creating the graphs presented on this page is available on GitHub.
References and Other Useful Links
*By accessing these datasets, you agree to the licence associated with each file, as indicated in parentheses below.
Updated January 2017